RFC7532
Internet Engineering Task Force (IETF) J. Lentini Request for Comments: 7532 NetApp Category: Standards Track R. Tewari ISSN: 2070-1721 IBM Almaden
C. Lever, Ed. Oracle Corporation March 2015
Namespace Database (NSDB) Protocol for Federated File Systems
Abstract
This document describes a file system federation protocol that enables file access and namespace traversal across collections of independently administered fileservers. The protocol specifies a set of interfaces by which fileservers with different administrators can form a fileserver federation that provides a namespace composed of the file systems physically hosted on and exported by the constituent fileservers.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7532.
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Contents
- 1 Introduction
- 2 Overview of Features and Concepts
- 3 Examples
- 4 NSDB Configuration and Schema
- 5 NSDB Operations
- 6 Security Considerations
- 7 IANA Considerations
- 8 Glossary
- 9 References
Introduction
A federated file system enables file access and namespace traversal in a uniform, secure, and consistent manner across multiple independent fileservers within an enterprise or across multiple enterprises.
This document specifies a set of protocols that allow fileservers, possibly from different vendors and with different administrators, to cooperatively form a federation containing one or more federated file systems. Each federated file system's namespace is composed of the file systems physically hosted on and exported by the federation's fileservers. A federation comprises a common namespace across all its fileservers. A federation can project multiple namespaces and enable clients to traverse each one. A federation can contain an arbitrary number of namespace repositories, each belonging to a different administrative entity and each rendering a part of the namespace. A federation might also have an arbitrary number of administrative entities responsible for administering disjoint subsets of the fileservers.
Traditionally, building a namespace that spans multiple fileservers has been difficult for two reasons. First, the fileservers that export pieces of the namespace are often not in the same administrative domain. Second, there is no standard mechanism for the fileservers to cooperatively present the namespace. Fileservers may provide proprietary management tools, and in some cases, an administrator may be able to use the proprietary tools to build a shared namespace out of the exported file systems. However, relying on vendor-specific proprietary tools does not work in larger enterprises or when collaborating across enterprises because the fileservers are likely to be from multiple vendors or use different software versions, each with their own namespace protocols, with no common mechanism to manage the namespace or exchange namespace information.
The federated file system protocols in this document define how to construct a namespace accessible by a Network File System (NFS) version 4.0 RFC7530, NFSv4.1 RFC5661, or newer client and have been designed to accommodate other file-access protocols in the future.
The requirements for federated file systems are described in RFC5716. A protocol for administering a fileserver's namespace is described in RFC7533. The mechanism for discovering the root of a federated namespace is described in RFC6641.
In the rest of the document, the term "fileserver" denotes a fileserver that is part of a federation.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC2119.
Overview of Features and Concepts
File-Access Protocol
A file-access protocol is a network protocol for accessing data. The NFSv4.0 protocol RFC7530 is an example of a file-access protocol.
File-Access Client
File-access clients are standard, off-the-shelf network-attached storage (NAS) clients that communicate with fileservers using a standard file-access protocol.
Fileserver
Fileservers are servers that store physical fileset data or refer file-access clients to other fileservers. A fileserver provides access to its shared file system data via a file-access protocol. A fileserver may be implemented in a number of different ways, including a single system, a cluster of systems, or some other configuration.
Referral
A referral is a mechanism by which a fileserver redirects a file- access client to a different fileserver or export. The exact information contained in a referral varies from one file-access protocol to another. The NFSv4.0 protocol, for example, defines the
fs_locations attribute for returning referral information to NFSv4.0 clients. The NFSv4.1 protocol introduces the fs_locations_info attribute that can return richer referral information to its clients. NFSv4.1 fileservers may use either attribute during a referral. Both attributes are defined in RFC5661.
Namespace
The goal of a unified namespace is to make all managed data available to any file-access client via the same path in a common file system namespace. This should be achieved with minimal or zero configuration on file-access clients. In particular, updates to the common namespace should not require configuration changes to any file-access client.
Filesets, which are the units of data management, are a set of files and directories. From the perspective of file-access clients, the common namespace is constructed by mounting filesets that are physically located on different fileservers. The namespace, which is defined in terms of fileset names and locations, is stored in a set of namespace repositories, each managed by an administrative entity.
The namespace schema defines the model used for populating, modifying, and querying the namespace repositories. It is not required by the federation that the namespace be common across all fileservers. It should be possible to have several independently rooted namespaces.
Fileset
A fileset is loosely defined as a set of files and the directory tree that contains them. The fileset abstraction is the basic unit of data management. Depending on the configuration, a fileset may be anything from an individual directory of an exported file system to an entire exported file system on a fileserver.
Fileset Name (FSN)
A fileset is uniquely represented by its fileset name (FSN). An FSN is considered unique across a federation. After an FSN is created, it is associated with one or more fileset locations (FSLs) on one or more fileservers.
An FSN consists of:
NsdbName: the network location of the Namespace Database (NSDB) node that contains authoritative information for this FSN.
FsnUuid: a UUID (universally unique identifier), conforming to RFC4122, that is used to uniquely identify an FSN.
FsnTTL: the time-to-live of the FSN's FSL information, in seconds. Fileservers MUST NOT use cached FSL records after the parent FSN's FsnTTL has expired. An FsnTTL value of zero indicates that fileservers MUST NOT cache the results of resolving this FSN.
The NsdbName is not physically stored as an attribute of the record. The NsdbName is obvious to any client that accesses an NSDB and is indeed authenticated in cases where Transport Layer Security (TLS) is in effect.
The FsnUuid and NsdbName values never change during an FSN's lifetime. However, an FSN's FSL information can change over time and is typically cached on fileservers for performance. More detail on FSL caching is provided in Section 2.8.3.
An FSN record may also contain:
Annotations: name/value pairs that can be interpreted by a fileserver. The semantics of this field are not defined by this document. These tuples are intended to be used by higher- level protocols.
Descriptions: text descriptions. The semantics of this field are not defined by this document.
Fileset Location (FSL)
An FSL describes one physical location where a complete copy of the fileset's data resides. An FSL contains generic and type-specific information that together describe how to access the fileset data at this location. An FSL's attributes can be used by a fileserver to decide which locations it will return to a file-access client.
An FSL consists of:
FslUuid: a UUID, conforming to RFC4122, that is used to uniquely identify an FSL.
FsnUuid: the UUID of the FSL's FSN.
NsdbName: the network location of the NSDB node that contains authoritative information for this FSL.
The NsdbName is not stored as an attribute of an FSL record for the same reason it is not stored in FSN records.
An FSL record may also contain:
Annotations: name/value pairs that can be interpreted by a fileserver. The semantics of this field are not defined by this document. These tuples are intended to be used by higher- level protocols.
Descriptions: text descriptions. The semantics of this field are not defined by this document.
In addition to the attributes defined above, an FSL record contains attributes that allow a fileserver to construct referrals. For each file-access protocol, a corresponding FSL record subtype is defined.
This document defines an FSL subtype for NFS. An NFS FSL contains information suitable for use in one of the NFSv4 referral attributes (e.g., fs_locations or fs_locations_info, described in RFC5661). Section 4.2.2.4 describes the contents of an NFS FSL record.
A fileset may also be accessible by file-access protocols other than NFS. The contents and format of such FSL subtypes are not defined in this document.
The NFS URI Scheme
To capture the location of an NFSv4 fileset, we extend the NFS URL scheme specified in RFC2224. This extension follows rules for defining Uniform Resource Identifier schemes (see RFC3986). In the following text, we refer to this extended NFS URL scheme as an NFS URI.
An NFS URI MUST contain both an authority and a path component. It MUST NOT contain a query component or a fragment component. Use of the familiar "nfs" scheme name is retained.
The NFS URI Authority Component
The rules for encoding the authority component of a generic URI are specified in section 3.2 of RFC3986. The authority component of an NFS URI MUST contain the host subcomponent. For globally scoped NFS URIs, a hostname used in such URIs SHOULD be a fully qualified domain name. See section 3.2.2 of RFC3986 for rules on encoding non-ASCII characters in hostnames.
An NFS URI MAY contain a port subcomponent as described in section 3.2.3 of RFC3986. If this subcomponent is missing, a port value of 2049 is assumed, as specified in RFC7530, Section 3.1.
The NFS URI Path Component
The rules for encoding the path component of a generic URI are specified in Section 3.3 of RFC3986.
According to Sections 5 and 6 of RFC2224, NFS URLs specify a pathname relative to an NFS fileserver's public filehandle. However, NFSv4 fileservers do not expose a public filehandle. Instead, NFSv4 pathnames contained in an NFS URI are evaluated relative to the pseudoroot of the fileserver identified in the URI's authority component.
Each component of an NFSv4 pathname is represented as a component4 string (see Section 3.2, "Basic Data Types", of RFC5661). The component4 elements of an NFSv4 pathname are encoded as path segments in an NFS URI. NFSv4 pathnames MUST be expressed in an NFS URI as an absolute path. An NFS URI path component MUST NOT be empty. The NFS URI path component starts with a slash ("/") character, followed by one or more path segments that each start with a slash ("/") character RFC3986.
Therefore, a double slash always follows the authority component of an NFS URI. For example, the NFSv4 pathname "/" is represented by two slash ("/") characters following an NFS URI's authority component.
The component names of an NFSv4 pathname MUST be prepared using the component name rules defined in Section 12 ("Internationalization") of RFC7530 prior to encoding the path component of an NFS URI. As specified in RFC3986, any non-ASCII characters and any URI-reserved characters, such as the slash ("/") character, contained in a component4 element MUST be represented by URI percent encoding.
Encoding an NFS Location in an FSL
The path component of an NFS URI encodes the rootpath field of the NFSv4 fs_location4 data type or the "fli_rootpath" of the NFSv4 fs_locations_item4 data type (see RFC5661).
In its server field, the NFSv4 fs_location4 data type contains a list of universal addresses and DNS labels. Each may optionally include a port number. The exact encoding requirements for this information is found in Section 12.6 of RFC7530. The NFSv4 fs_locations_item4 data type encodes the same data in its fli_entries field (see RFC5661). This information is encoded in the authority component of an NFS URI.
The server and fli_entries fields can encode multiple server hostnames that share the same pathname. An NFS URI, and hence an FSL record, represents only a single hostname and pathname pair. An NFS fileserver MUST NOT combine a set of FSL records into a single fs_location4 or fs_locations_item4 unless each FSL record in the set contains the same rootpath value and extended file system information.
Mutual Consistency across Fileset Locations
All of the FSLs that have the same FSN (and thereby reference the same fileset) are equivalent from the point of view of access by a file-access client. Different fileset locations for an FSN represent the same data, though potentially at different points in time. Fileset locations are equivalent but not identical. Locations may be either read-only or read-write. Typically, multiple read-write locations are backed by a clustered file system while read-only locations are replicas created by a federation-initiated or external replication operation. Read-only locations may represent consistent point-in-time copies of a read-write location. The federation protocols, however, cannot prevent subsequent changes to a read-only location nor guarantee point-in-time consistency of a read-only location if the read-write location is changing.
Regardless of the type, one file-access client may be referred to a location described by one FSL while another client chooses to use a location described by another FSL. Since updates to each fileset location are not controlled by the federation protocol, it is the responsibility of administrators to guarantee the functional equivalence of the data.
The federation protocols do not guarantee that different fileset locations are mutually consistent in terms of the currency of their data. However, they provide a means to publish currency information
so that all fileservers in a federation can convey the same information to file-access clients during referrals. Clients use this information to ensure they do not revert to an out-of-date version of a fileset's data when switching between fileset locations. NFSv4.1 provides guidance on how replication can be handled in such a manner. In particular, see Section 11.7 of RFC5661.
Caching of Fileset Locations
To resolve an FSN to a set of FSL records, a fileserver queries the NSDB node named in the FSN for FSL records associated with this FSN. The parent FSN's FsnTTL attribute (see Section 2.7) specifies the period of time during which a fileserver may cache these FSL records.
The combination of FSL caching and FSL migration presents a challenge. For example, suppose there are three fileservers named A, B, and C. Suppose further that fileserver A contains a junction J to fileset X stored on fileserver B (see Section 2.10 for a description of junctions).
Now suppose that fileset X is migrated from fileserver B to fileserver C, and the corresponding FSL information for fileset X in the authoritative NSDB is updated.
If fileserver A has cached FSLs for fileset X, a file-access client traversing junction J on fileserver A will be referred to fileserver B, even though fileset X has migrated to fileserver C. If fileserver A had not cached the FSL records, it would have queried the NSDB and obtained the correct location of fileset X.
Typically, the process of fileset migration leaves a redirection on the source fileserver in place of a migrated fileset (without such a redirection, file-access clients would find an empty space where the migrated fileset was, which defeats the purpose of a managed migration).
This redirection might be a new junction that targets the same FSN as other junctions referring to the migrated fileset, or it might be some other kind of directive, depending on the fileserver implementation, that simply refers file-access clients to the new location of the migrated fileset.
Back to our example. Suppose, as part of the migration process, a junction replaces fileset X on fileserver B. Later, either:
o New file-access clients are referred to fileserver B by stale FSL
information cached on fileserver A, or
o File-access clients continue to access fileserver B because they
cache stale location data for fileset X.
In either case, thanks to the redirection, file-access clients are informed by fileserver B that fileset X has moved to fileserver C.
Such redirecting junctions (here, on fileserver B) would not be required to be in place forever. They need to stay in place at least until FSL entries cached on fileservers and locations cached on file- access clients for the target fileset are invalidated.
The FsnTTL field in the FSL's parent FSN (see Section 2.7) specifies an upper bound for the lifetime of cached FSL information and thus can act as a lower bound for the lifetime of redirecting junctions.
For example, suppose the FsnTTL field contains the value 3600 seconds (one hour). In such a case, administrators SHOULD keep the redirection in place for at least one hour after a fileset migration has taken place because a referring fileserver might cache the FSL data during that time before refreshing it.
To get file-access clients to access the destination fileserver more quickly, administrators SHOULD set the FsnTTL field of the migrated fileset to a low number or zero before migration begins. It can be reset to a more reasonable number at a later point.
Note that some file-access protocols do not communicate location cache expiry information to file-access clients. In some cases, it may be difficult to determine an appropriate lifetime for redirecting junctions because file-access clients may cache location information indefinitely.
Generating a Referral from Fileset Locations
After resolving an FSN to a set of FSL records, the fileserver generates a referral to redirect a file-access client to one or more of the FSN's FSLs. The fileserver converts the FSL records to a referral format understood by a particular file-access client, such as an NFSv4 fs_locations or fs_locations_info attribute.
To give file-access clients as many options as possible, the fileserver SHOULD include the maximum possible number of FSL records in a referral. However, the fileserver MAY omit some of the FSL records from the referral. For example, the fileserver might omit an FSL record because of limitations in the file-access protocol's referral format.
For a given FSL record, the fileserver MAY convert or reduce the FSL record's contents in a manner appropriate to the referral format. For example, an NFS FSL record contains all the data necessary to construct an fs_locations_info attribute, but an fs_locations_info attribute contains several pieces of information that are not found in the simpler fs_locations attribute. A fileserver constructs entries in an fs_locations attribute using the relevant contents of an NFS FSL record.
Whenever the fileserver converts or reduces FSL data, the fileserver SHOULD attempt to maintain the original meaning where possible. For example, an NFS FSL record contains the rank and order information that is included in an fs_locations_info attribute (see NFSv4.1's FSLI4BX_READRANK, FSLI4BX_READORDER, FSLI4BX_WRITERANK, and FSLI4BX_WRITEORDER). While this rank and order information is not explicitly expressible in an fs_locations attribute, the fileserver can arrange the fs_locations attribute's locations list based on the rank and order values.
Another example: A single NFS FSL record contains the hostname of one fileserver. A single fs_locations attribute can contain a list of fileserver names. An NFS fileserver MAY combine two or more FSL records into a single entry in an fs_locations or fs_locations_info array only if each FSL record contains the same pathname and extended file system information.
Refer to Sections 11.9 and 11.10 of the NFSv4.1 protocol specification RFC5661 for further details.
Namespace Database (NSDB)
The NSDB service is a federation-wide service that provides interfaces to define, update, and query FSN information, FSL information, and FSN-to-FSL mapping information.
An individual repository of namespace information is called an NSDB node. The difference between the NSDB service and an NSDB node is analogous to that between the DNS service and a particular DNS server.
Each NSDB node is managed by a single administrative entity. A single administrative entity can manage multiple NSDB nodes.
Each NSDB node stores the definition of the FSNs for which it is authoritative. It also stores the definitions of the FSLs associated with those FSNs. An NSDB node is authoritative for the filesets that it defines.
An NSDB MAY be replicated throughout the federation. If an NSDB is replicated, the NSDB MUST exhibit loose, converging consistency as defined in RFC3254. The mechanism by which this is achieved is outside the scope of this document. Many Lightweight Directory Access Protocol (LDAP) implementations support replication. These features MAY be used to replicate the NSDB.
NSDB Client
Each NSDB node supports an LDAP RFC4510 interface. An NSDB client is software that uses the LDAP protocol to access or update namespace information stored on an NSDB node.
A domain's administrative entity uses NSDB client software to manage information stored on NSDB nodes. Details of these transactions are discussed in Section 5.1.
Fileservers act as an NSDB client when contacting a particular NSDB node to resolve an FSN to a set of FSL records. The resulting location information is then transferred to file-access clients via referrals. Therefore, file-access clients never need to access NSDBs directly. These transactions are described in Section 5.2.
2.10. Junctions and Referrals
A junction is a point in a particular fileset namespace where a specific target fileset may be attached. If a file-access client traverses the path leading from the root of a federated namespace to the junction referring to a target fileset, it should be able to mount and access the data in that target fileset (assuming appropriate permissions). In other words, a junction can be viewed as a reference from a directory in one fileset to the root of the target fileset.
A junction can be implemented as a special marker on a directory or by some other mechanism in the fileserver's underlying file system. What data is used by the fileserver to represent junctions is not defined by this document. The essential property is that given a junction, a fileserver must be able to find the FSN for the target fileset.
When a file-access client reaches a junction, the fileserver refers the client to a list of FSLs associated with the FSN targeted by the junction. The client can then mount one of the associated FSLs.
The federation protocols do not limit where and how many times a fileset is mounted in the namespace. Filesets can be nested; a fileset can be mounted under another fileset.
2.11. Unified Namespace and the Root Fileset
The root fileset, when defined, is the top-level fileset of the federation-wide namespace. The root of the unified namespace is the top level directory of this fileset. A set of designated fileservers in the federation can export the root fileset to render the federation-wide unified namespace. When a file-access client mounts the root fileset from any of these designated fileservers, it can view a common federation-wide namespace.
2.12. UUID Considerations
To ensure FSN and FSL records are unique across a domain, Federated File System (FedFS) employs UUIDs conforming to RFC4122 to form the distinguished names of LDAP records containing FedFS data (see Section 4.2.2.2).
Because junctions store a tuple containing an FSN UUID and the name and port of an NSDB node, an FSN UUID must be unique only on a single NSDB node. An FSN UUID collision can be detected immediately when an administrator attempts to publish an FSN or FSL by storing it under a specific NSDB Container Entry (NCE) on an authoritative NSDB host.
Note that one NSDB node may store multiple NCEs, each under a different namingContext. If an NSDB node must contain more than one NCE, the federation's admin entity SHOULD provide a robust method for preventing FSN UUID collisions between FSNs that reside on the same NSDB node but under different NCEs.
Because FSLs are children of FSNs, FSL UUIDs must be unique for just a single FSN. As with FSNs, as soon as an FSL is published, its uniqueness is guaranteed.
A fileserver performs the operations described in Section 5.2 as an unauthenticated user. Thus, distinguished names of FSN and FSL records, as well as the FSN and FSL records themselves, are required to be readable by anyone who can bind anonymously to an NSDB node. Therefore, FSN and FSL UUIDs should be considered public information.
Version 1 UUIDs contain a host's Media Access Control (MAC) address and a timestamp in the clear. This gives provenance to each UUID, but attackers can use such details to guess information about the host where the UUID was generated. Security-sensitive installations should be aware that on externally facing NSDBs, UUIDs can reveal information about the hosts where they are generated.
In addition, version 1 UUIDs depend on the notion that a hardware MAC address is unique across machines. As virtual machines do not depend on unique physical MAC addresses and, in any event, an administrator can modify the physical MAC address, version 1 UUIDs are no longer considered sufficient.
To minimize the probability of UUIDs colliding, a consistent procedure for generating UUIDs should be used throughout a federation. Within a federation, UUIDs SHOULD be generated using the procedure described for version 4 of the UUID variant specified in RFC4122.
Examples
In this section we provide examples and discussion of the basic operations facilitated by the federated file system protocol: creating a fileset, adding a replica of a fileset, resolving a junction, and creating a junction.
Creating a Fileset and Its FSL(s)
A fileset is the abstraction of a set of files and the directory tree that contains them. The fileset abstraction is the fundamental unit of data management in the federation. This abstraction is implemented by an actual directory tree whose root location is specified by a fileset location (FSL).
In this section, we describe the basic requirements for starting with a directory tree and creating a fileset that can be used in the federation protocols. Note that we do not assume that the process of creating a fileset requires any transformation of the files or the directory hierarchy. The only thing that is required by this process is assigning the fileset a fileset name (FSN) and expressing the location of the implementation of the fileset as an FSL.
There are many possible variations to this procedure, depending on how the FSN that binds the FSL is created and whether other replicas of the fileset exist, are known to the federation, and need to be bound to the same FSN.
It is easiest to describe this in terms of how to create the initial implementation of the fileset and then describe how to add replicas.
Creating a Fileset and an FSN
The following administrative steps create an FSN, which is used to track all replicas of a single physical dataset.
1. Choose the NSDB node that will keep track of the FSL(s) and
related information for the fileset.
2. Create an FSN in the NSDB node.
The FSN UUID is chosen by the administrator or generated automatically by administration software. The former case is used if the fileset is being restored, perhaps as part of disaster recovery, and the administrator wishes to specify the FSN UUID in order to permit existing junctions that reference that FSN to work again.
At this point, the FSN exists, but its fileset locations are unspecified.
3. For the FSN created above, create an FSL in the NSDB node that
describes the physical location of the fileset data.
Adding a Replica of a Fileset
Adding a replica is straightforward: the NSDB node and the FSN are already known. The only remaining step is to add another FSL.
Note that the federation protocols provide only the mechanisms to register and unregister replicas of a fileset. Fileserver-to- fileserver replication protocols are not defined.
Junction Resolution
A fileset may contain references to other filesets. These references are represented by junctions. If a file-access client requests access to a fileset object that is a junction, the fileserver resolves the junction to discover one or more FSLs that implement the referenced fileset.
There are many possible variations to this procedure, depending on how the junctions are represented by the fileserver and how the fileserver performs junction resolution.
Step 4 is the only step that interacts directly with the federation protocols. The rest of the steps may use platform-specific interfaces.
1. The fileserver determines that the object being accessed is a
junction.
2. The fileserver does a local lookup to find the FSN of the target
fileset.
3. Using the FSN, the fileserver finds the NSDB node responsible for
the target FSN.
4. The fileserver contacts that NSDB node and asks for the set of
FSLs that implement the target FSN. The NSDB node responds with a (possibly empty) set of FSLs.
5. The fileserver converts one or more of the FSLs to the location
type used by the file-access client (e.g., an NFSv4 fs_locations attribute as described in RFC5661).
6. The fileserver redirects (in whatever manner is appropriate for
the client) the client to the location(s).
Example Use Cases for Fileset Annotations
Fileset annotations can convey additional attributes of a fileset. For example, fileset annotations can be used to define relationships between filesets that can be used by an auxiliary replication protocol. Consider the scenario where a fileset is created and mounted at some point in the namespace. A snapshot of the read-write FSL of that fileset is taken periodically at different frequencies (say, a daily or weekly snapshot). The different snapshots are mounted at different locations in the namespace.
The daily snapshots are considered as different filesets from the weekly ones, but both are related to the source fileset. We can define an annotation labeling the filesets as source and replica. The replication protocol can use this information to copy data from one or more FSLs of the source fileset to all the FSLs of the replica fileset. The replica filesets are read-only while the source fileset is read-write.
This follows the traditional Andrew File System (AFS) model of mounting the read-only volume at a path in the namespace different from that of the read-write volume [AFS].
The federation protocol does not control or manage the relationship among filesets. It merely enables annotating the filesets with user- defined relationships.
Another potential use for annotations is recording references to an FSN. A single annotation containing the number of references could be defined, or multiple annotations, one per reference, could be used to store detailed information on the location of each reference.
As with the replication annotation described above, the maintenance of reference information would not be controlled by the federation protocol. The information would most likely be non-authoritative because the ability to create a junction does not require the authority to update the FSN record. In any event, such annotations could be useful to administrators for determining if an FSN is referenced by a junction.
NSDB Configuration and Schema
This section describes how an NSDB is constructed using an LDAP Version 3 RFC4510 directory. Section 4.1 describes the basic properties of the LDAP configuration that MUST be used in order to ensure compatibility between different implementations. Section 4.2 defines the new LDAP attribute types and the new object types; it also specifies how the distinguished name (DN) of each object instance MUST be constructed.
LDAP Configuration
An NSDB is constructed using an LDAP directory. This LDAP directory MAY have multiple naming contexts. The LDAP directory's entry specific to Digital Signature Algorithm (DSA) (its rootDSE) has a multi-valued namingContext attribute. Each value of the namingContext attribute is the DN of a naming context's root entry (see RFC4512).
For each naming context that contains federation entries (e.g., FSNs and FSLs):
1. There MUST be an LDAP entry that is superior to all of the naming
context's federation entries in the Directory Information Tree (DIT). This entry is termed the NSDB Container Entry (NCE). The NCE's children are FSNs. An FSN's children are FSLs.
2. The naming context's root entry MUST include
"fedfsNsdbContainerInfo" (defined in Section 4.2.2.1) as one of its object classes. The fedfsNsdbContainerInfo's fedfsNceDN attribute is used to locate the naming context's NCE.
If a naming context does not contain federation entries, it will not contain an NCE, and its root entry will not include a "fedfsNsdbContainerInfo" as one of its object classes.
A fedfsNsdbContainerInfo's fedfsNceDN attribute contains the distinguished name (DN) of the NSDB Container Entry residing under this naming context. The fedfsNceDN attribute MUST NOT be empty.
For example, an LDAP directory might have the following entries:
-+ [root DSE] | namingContext: o=fedfs | namingContext: dc=example,dc=com | namingContext: ou=system | | +---- [o=fedfs] | fedfsNceDN: o=fedfs | | +---- [dc=example,dc=com] | fedfsNceDN: ou=fedfs,ou=corp-it,dc=example,dc=com | | +---- [ou=system]
In this case, the "o=fedfs" namingContext has an NSDB Container Entry at "o=fedfs", the "dc=example,dc=com" namingContext has an NSDB Container Entry at "ou=fedfs,ou=corp-it,dc=example,dc=com", and the "ou=system" namingContext has no NSDB Container Entry.
The NSDB SHOULD be configured with one or more privileged LDAP users. These users are able to modify the contents of the LDAP database. An administrator that performs the operations described in Section 5.1 SHOULD authenticate using the DN of a privileged LDAP user.
It MUST be possible for an unprivileged (unauthenticated) user to perform LDAP queries that access the NSDB data. A fileserver performs the operations described in Section 5.2 as an unprivileged user.
All implementations SHOULD use the same schema. At minimum, each MUST use a schema that includes all objects named in the following sections, with all associated attributes. If it is necessary for an
implementation to extend the schema defined here, consider using one of the following ways to extend the schema:
o Define a fedfsAnnotation key and values (see Section 4.2.1.6).
Register the new key and values with IANA (see Section 7.1).
o Define additional attribute types and object classes, then have
entries inherit from a class defined in this document and from the implementation-defined ones.
Given the above configuration guidelines, an NSDB SHOULD be constructed using a dedicated LDAP server. If LDAP directories are needed for other purposes, such as to store user account information, use of a separate LDAP server for those is RECOMMENDED. By using an LDAP server dedicated to storing NSDB records, there is no need to disturb the configuration of any other LDAP directories that store information unrelated to an NSDB.
LDAP Schema
The schema definitions provided in this document use the LDAP schema syntax defined in RFC4512. The definitions are formatted to allow the reader to easily extract them from the document. The reader can use the following shell script to extract the definitions:
#!/bin/sh
grep '^ *///' | sed 's?^ */// ??' | sed 's?^ *///$??'
If the above script is stored in a file called "extract.sh", and this
document is in a file called "spec.txt", then the reader can do:
sh extract.sh < spec.txt > fedfs.schema
The effect of the script is to remove leading white space from each
line, plus a sentinel sequence of "///".
Code components extracted from this document must include the
following license:
/// #
/// # Copyright (c) 2015 IETF Trust and the persons identified
/// # as authors of the code. All rights reserved.
/// #
/// # The authors of the code are:
/// # J. Lentini, C. Everhart, D. Ellard, R. Tewari, and M. Naik.
/// #
/// # Redistribution and use in source and binary forms, with
/// # or without modification, are permitted provided that the
/// # following conditions are met:
/// #
/// # - Redistributions of source code must retain the above
/// # copyright notice, this list of conditions and the
/// # following disclaimer.
/// #
/// # - Redistributions in binary form must reproduce the above
/// # copyright notice, this list of conditions and the
/// # following disclaimer in the documentation and/or other
/// # materials provided with the distribution.
/// #
/// # - Neither the name of Internet Society, IETF or IETF
/// # Trust, nor the names of specific contributors, may be
/// # used to endorse or promote products derived from this
/// # software without specific prior written permission.
/// #
/// # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS
/// # AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
/// # WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
/// # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
/// # FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
/// # EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
/// # LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
/// # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
/// # NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
/// # SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
/// # INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
/// # LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
/// # OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
/// # IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
/// # ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
/// #
LDAP Attributes
The following definitions are used in this document:
o The name attribute described in RFC4519.
o The Integer syntax (1.3.6.1.4.1.1466.115.121.1.27) described in
RFC4517.
o The integerMatch rule described in RFC4517.
o The Octet String syntax (1.3.6.1.4.1.1466.115.121.1.40) described
in RFC4517.
o The octetStringMatch rule described in RFC4517.
o The Boolean syntax (1.3.6.1.4.1.1466.115.121.1.7) described in
RFC4517.
o The booleanMatch rule described in RFC4517.
o The distinguishedNameMatch rule described in RFC4517.
o The DN syntax (1.3.6.1.4.1.1466.115.121.1.12) described in
RFC4517.
o The labeledURI attribute described in RFC2079.
o The UUID syntax (1.3.6.1.1.16.1) described in RFC4530.
o The UuidMatch rule described in RFC4530.
o The UuidOrderingMatch rule described in RFC4530.
fedfsUuid
A fedfsUuid is the base type for all of the universally unique
identifiers (UUIDs) used by the federated file system protocols.
The fedfsUuid type is based on rules and syntax defined in RFC4530.
A fedfsUuid is a single-valued LDAP attribute.
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.1 NAME 'fedfsUuid'
/// DESC 'A UUID used by NSDB'
/// EQUALITY uuidMatch
/// ORDERING uuidOrderingMatch
/// SYNTAX 1.3.6.1.1.16.1
/// SINGLE-VALUE
/// )
///
fedfsFsnUuid
A fedfsFsnUuid represents the UUID component of an FSN. An NSDB
SHOULD ensure that no two FSNs it stores have the same fedfsFsnUuid.
This attribute is single-valued.
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.4 NAME 'fedfsFsnUuid'
/// DESC 'The FSN UUID component of an FSN'
/// SUP fedfsUuid
/// SINGLE-VALUE
/// )
///
fedfsFsnTTL
A fedfsFsnTTL is the time-to-live in seconds of a cached FSN and its
child FSL records. It corresponds to the FsnTTL as defined in
Section 2.7. See also Section 2.8.3 for information about caching
FSLs. A fedfsFsnTTL MUST be encoded as an Integer syntax value
RFC4517 in the range [0, 4294967295].
This attribute is single-valued.
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.11 NAME 'fedfsFsnTTL'
/// DESC 'Time to live of an FSN tree'
/// EQUALITY integerMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.27 is the Integer syntax RFC4517.
fedfsNceDN
A fedfsNceDN stores a distinguished name (DN).
This attribute is single-valued.
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.14 NAME 'fedfsNceDN'
/// DESC 'NCE Distinguished Name'
/// EQUALITY distinguishedNameMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.12
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.12 is the DN syntax RFC4517.
fedfsFslUuid
A fedfsFslUuid represents the UUID of an FSL. An NSDB SHOULD ensure
that no two FSLs it stores have the same fedfsFslUuid.
This attribute is single-valued.
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.8 NAME 'fedfsFslUuid'
/// DESC 'UUID of an FSL'
/// SUP fedfsUuid
/// SINGLE-VALUE
/// )
///
fedfsAnnotation
A fedfsAnnotation contains an object annotation formatted as a key/
value pair.
This attribute is multi-valued; an object type that permits
annotations may have any number of annotations per instance.
A fedfsAnnotation attribute is a human-readable sequence of UTF-8
characters with no non-terminal NUL characters. The value MUST be
formatted according to the following ABNF RFC5234 rules:
ANNOTATION = KEY "=" VALUE
KEY = ITEM
VALUE = ITEM
ITEM = *WSP DQUOTE UTF8-octets DQUOTE *WSP
DQUOTE and WSP are defined in RFC5234, and UTF8-octets is defined
in RFC3629.
The following escape sequences are allowed:
+-----------------+-------------+
| escape sequence | replacement |
+-----------------+-------------+
| \\ | \ |
| \" | " |
+-----------------+-------------+
A fedfsAnnotation value might be processed as follows:
1. Parse the attribute value according to the ANNOTATION rule,
ignoring the escape sequences above.
2. Scan through results of the previous step and replace the escape
sequences above.
A fedfsAnnotation attribute that does not adhere to this format
SHOULD be ignored in its entirety. It MUST NOT prevent further
processing of its containing entry.
The following are examples of valid fedfsAnnotation attributes:
"key1" = "foo"
"another key" = "x=3"
"key-2" = "A string with \" and \\ characters."
"key3"="bar"
These correspond to the following key/value pairs:
+-------------+-----------------------------------+
| key | value |
+-------------+-----------------------------------+
| key1 | foo |
| another key | x=3 |
| key-2 | A string with " and \ characters. |
| key3 | bar |
+-------------+-----------------------------------+
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.12 NAME 'fedfsAnnotation'
/// DESC 'Annotation of an object'
/// SUP name
/// )
///
fedfsDescr
A fedfsDescr stores an object description. The description MUST be
encoded as a UTF-8 string.
This attribute is multi-valued, which permits any number of
descriptions per entry.
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.13 NAME 'fedfsDescr'
/// DESC 'Description of an object'
/// SUP name
/// )
///
fedfsNfsURI
A fedfsNfsURI stores the host and pathname components of an FSL. A
fedfsNfsURI MUST be encoded as an NFS URI (see Section 2.8.1).
The fedfsNfsURI is a subtype of the labeledURI type RFC2079, with
the same encoding rules.
This attribute is single-valued.
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.120 NAME 'fedfsNfsURI'
/// DESC 'Location of fileset'
/// SUP labeledURI
/// SINGLE-VALUE
/// )
///
fedfsNfsCurrency
A fedfsNfsCurrency stores the NFSv4.1 fs_locations_server's
fls_currency value RFC5661. A fedfsNfsCurrency MUST be encoded as
an Integer syntax value RFC4517 in the range [-2147483648,
2147483647].
This attribute is single-valued.
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.103 NAME 'fedfsNfsCurrency'
/// DESC 'up-to-date measure of the data'
/// EQUALITY integerMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.27 is the Integer syntax RFC4517.
4.2.1.10. fedfsNfsGenFlagWritable
A fedfsNfsGenFlagWritable stores the value of an FSL's NFSv4.1
FSLI4GF_WRITABLE bit RFC5661. A value of "TRUE" indicates the bit
is set. A value of "FALSE" indicates the bit is not set.
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.104 NAME 'fedfsNfsGenFlagWritable'
/// DESC 'Indicates if the file system is writable'
/// EQUALITY booleanMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.7
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.7 is the Boolean syntax RFC4517.
4.2.1.11. fedfsNfsGenFlagGoing
A fedfsNfsGenFlagGoing stores the value of an FSL's NFSv4.1
FSLI4GF_GOING bit RFC5661. A value of "TRUE" indicates the bit is
set. A value of "FALSE" indicates the bit is not set.
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.105 NAME 'fedfsNfsGenFlagGoing'
/// DESC 'Indicates if the file system is going'
/// EQUALITY booleanMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.7
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.7 is the Boolean syntax RFC4517.
4.2.1.12. fedfsNfsGenFlagSplit
A fedfsNfsGenFlagSplit stores the value of an FSL's NFSv4.1
FSLI4GF_SPLIT bit RFC5661. A value of "TRUE" indicates the bit is
set. A value of "FALSE" indicates the bit is not set.
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.106 NAME 'fedfsNfsGenFlagSplit'
/// DESC 'Indicates if there are multiple file systems'
/// EQUALITY booleanMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.7
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.7 is the Boolean syntax RFC4517.
4.2.1.13. fedfsNfsTransFlagRdma
A fedfsNfsTransFlagRdma stores the value of an FSL's NFSv4.1
FSLI4TF_RDMA bit RFC5661. A value of "TRUE" indicates the bit is
set. A value of "FALSE" indicates the bit is not set.
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.107 NAME 'fedfsNfsTransFlagRdma'
/// DESC 'Indicates if the transport supports RDMA'
/// EQUALITY booleanMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.7
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.7 is the Boolean syntax RFC4517.
4.2.1.14. fedfsNfsClassSimul
A fedfsNfsClassSimul contains the FSL's NFSv4.1 FSLI4BX_CLSIMUL
RFC5661 value. A fedfsNfsClassSimul MUST be encoded as an Integer
syntax value RFC4517 in the range [0, 255].
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.108 NAME 'fedfsNfsClassSimul'
/// DESC 'The simultaneous-use class of the file system'
/// EQUALITY integerMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.27 is the Integer syntax RFC4517.
4.2.1.15. fedfsNfsClassHandle
A fedfsNfsClassHandle contains the FSL's NFSv4.1 FSLI4BX_CLHANDLE
RFC5661 value. A fedfsNfsClassHandle MUST be encoded as an Integer
syntax value RFC4517 in the range [0, 255].
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.109 NAME 'fedfsNfsClassHandle'
/// DESC 'The handle class of the file system'
/// EQUALITY integerMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.27 is the Integer syntax RFC4517.
4.2.1.16. fedfsNfsClassFileid
A fedfsNfsClassFileid contains the FSL's NFSv4.1 FSLI4BX_CLFILEID
RFC5661 value. A fedfsNfsClassFileid MUST be encoded as an Integer
syntax value RFC4517 in the range [0, 255].
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.110 NAME 'fedfsNfsClassFileid'
/// DESC 'The fileid class of the file system'
/// EQUALITY integerMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.27 is the Integer syntax RFC4517.
4.2.1.17. fedfsNfsClassWritever
A fedfsNfsClassWritever contains the FSL's NFSv4.1 FSLI4BX_CLWRITEVER
RFC5661 value. A fedfsNfsClassWritever MUST be encoded as an
Integer syntax value RFC4517 in the range [0, 255].
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.111 NAME 'fedfsNfsClassWritever'
/// DESC 'The write-verifier class of the file system'
/// EQUALITY integerMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.27 is the Integer syntax RFC4517.
4.2.1.18. fedfsNfsClassChange
A fedfsNfsClassChange contains the FSL's NFSv4.1 FSLI4BX_CLCHANGE
RFC5661 value. A fedfsNfsClassChange MUST be encoded as an Integer
syntax value RFC4517 in the range [0, 255].
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.112 NAME 'fedfsNfsClassChange'
/// DESC 'The change class of the file system'
/// EQUALITY integerMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.27 is the Integer syntax RFC4517.
4.2.1.19. fedfsNfsClassReaddir
A fedfsNfsClassReaddir contains the FSL's NFSv4.1 FSLI4BX_CLREADDIR
RFC5661 value. A fedfsNfsClassReaddir MUST be encoded as an
Integer syntax value RFC4517 in the range [0, 255].
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.113 NAME 'fedfsNfsClassReaddir'
/// DESC 'The readdir class of the file system'
/// EQUALITY integerMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.27 is the Integer syntax RFC4517.
4.2.1.20. fedfsNfsReadRank
A fedfsNfsReadRank contains the FSL's NFSv4.1 FSLI4BX_READRANK
RFC5661 value. A fedfsNfsReadRank MUST be encoded as an Integer
syntax value RFC4517 in the range [0, 255].
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.114 NAME 'fedfsNfsReadRank'
/// DESC 'The read rank of the file system'
/// EQUALITY integerMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.27 is the Integer syntax RFC4517.
4.2.1.21. fedfsNfsReadOrder
A fedfsNfsReadOrder contains the FSL's NFSv4.1 FSLI4BX_READORDER
RFC5661 value. A fedfsNfsReadOrder MUST be encoded as an Integer
syntax value RFC4517 in the range [0, 255].
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.115 NAME 'fedfsNfsReadOrder'
/// DESC 'The read order of the file system'
/// EQUALITY integerMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.27 is the Integer syntax RFC4517.
4.2.1.22. fedfsNfsWriteRank
A fedfsNfsWriteRank contains the FSL's FSLI4BX_WRITERANK RFC5661
value. A fedfsNfsWriteRank MUST be encoded as an Integer syntax
value RFC4517 in the range [0, 255].
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.116 NAME 'fedfsNfsWriteRank'
/// DESC 'The write rank of the file system'
/// EQUALITY integerMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.27 is the Integer syntax RFC4517.
4.2.1.23. fedfsNfsWriteOrder
A fedfsNfsWriteOrder contains the FSL's FSLI4BX_WRITEORDER RFC5661
value. A fedfsNfsWriteOrder MUST be encoded as an Integer syntax
value RFC4517 in the range [0, 255].
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.117 NAME 'fedfsNfsWriteOrder'
/// DESC 'The write order of the file system'
/// EQUALITY integerMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.27 is the Integer syntax RFC4517.
4.2.1.24. fedfsNfsVarSub
A fedfsNfsVarSub stores the value of an FSL's NFSv4.1 FSLI4IF_VAR_SUB
bit RFC5661. A value of "TRUE" indicates the bit is set. A value
of "FALSE" indicates the bit is not set.
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.118 NAME 'fedfsNfsVarSub'
/// DESC 'Indicates if variable substitution is present'
/// EQUALITY booleanMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.7
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.7 is the Boolean syntax RFC4517.
4.2.1.25. fedfsNfsValidFor
A fedfsNfsValidFor stores an FSL's NFSv4.1 fs_locations_info
fli_valid_for value RFC5661. A fedfsNfsValidFor MUST be encoded as
an Integer syntax value RFC4517 in the range [-2147483648,
2147483647].
An FSL's parent's fedfsFsnTTL value and its fedfsNfsValidFor value
MAY be different.
This attribute is single-valued.
///
/// attributetype (
/// 1.3.6.1.4.1.31103.1.19 NAME 'fedfsNfsValidFor'
/// DESC 'Valid for time'
/// EQUALITY integerMatch
/// SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
/// SINGLE-VALUE
/// )
///
OID 1.3.6.1.4.1.1466.115.121.1.27 is the Integer syntax RFC4517.
LDAP Object Classes
fedfsNsdbContainerInfo
A fedfsNsdbContainerInfo describes the location of the NCE.
A fedfsNsdbContainerInfo's fedfsNceDN attribute is REQUIRED.
A fedfsNsdbContainerInfo's fedfsAnnotation and fedfsDescr attributes
are OPTIONAL.
///
/// objectclass (
/// 1.3.6.1.4.1.31103.1.1001 NAME 'fedfsNsdbContainerInfo'
/// DESC 'Describes NCE location'
/// SUP top AUXILIARY
/// MUST (
/// fedfsNceDN
/// )
/// MAY (
/// fedfsAnnotation
/// $ fedfsDescr
/// ))
///
fedfsFsn
A fedfsFsn represents an FSN.
A fedfsFsn's fedfsFsnUuid and fedfsFsnTTL attributes are REQUIRED.
A fedfsFsn's fedfsAnnotation and fedfsDescr attributes are OPTIONAL.
The DN of an FSN is REQUIRED to take the following form:
"fedfsFsnUuid=$FSNUUID,$NCE", where $FSNUUID is the UUID of the FSN
and $NCE is the DN of the NCE. Since LDAP requires a DN to be
unique, this ensures that each FSN entry has a unique UUID value
within the LDAP directory.
///
/// objectclass (
/// 1.3.6.1.4.1.31103.1.1002 NAME 'fedfsFsn'
/// DESC 'Represents a fileset'
/// SUP top STRUCTURAL
/// MUST (
/// fedfsFsnUuid
/// $ fedfsFsnTTL
/// )
/// MAY (
/// fedfsAnnotation
/// $ fedfsDescr
/// ))
///
fedfsFsl
The fedfsFsl object class represents an FSL.
The fedfsFsl is an abstract object class. Protocol-specific subtypes
of this object class are used to store FSL information. The
fedfsNfsFsl object class defined in Section 4.2.2.4 is used to record
an NFS FSL's location. Other subtypes MAY be defined for other
protocols (e.g., Common Internet File System (CIFS)).
A fedfsFsl's fedfsFslUuid and fedfsFsnUuid attributes are REQUIRED.
A fedfsFsl's fedfsAnnotation and fedfsDescr attributes are OPTIONAL.
The DN of an FSL is REQUIRED to take the following form:
"fedfsFslUuid=$FSLUUID,fedfsFsnUuid=$FSNUUID,$NCE", where $FSLUUID is
the FSL's UUID, $FSNUUID is the FSN's UUID, and $NCE is the DN of the
NCE. Since LDAP requires a DN to be unique, this ensures that each
FSL entry has a unique UUID value within the LDAP directory.
///
/// objectclass (
/// 1.3.6.1.4.1.31103.1.1003 NAME 'fedfsFsl'
/// DESC 'A physical location of a fileset'
/// SUP top ABSTRACT
/// MUST (
/// fedfsFslUuid
/// $ fedfsFsnUuid
/// )
/// MAY (
/// fedfsAnnotation
/// $ fedfsDescr
/// ))
///
fedfsNfsFsl
A fedfsNfsFsl is used to represent an NFS FSL. The fedfsNfsFsl
inherits all of the attributes of the fedfsFsl and extends the
fedfsFsl with information specific to the NFS protocol.
The DN of an NFS FSL is REQUIRED to take the following form:
"fedfsFslUuid=$FSLUUID,fedfsFsnUuid=$FSNUUID,$NCE", where $FSLUUID is
the FSL's UUID, $FSNUUID is the FSN's UUID, and $NCE is the DN of the
NCE. Since LDAP requires a DN to be unique, this ensures that each
NFS FSL entry has a unique UUID value within the LDAP directory.
///
/// objectclass (
/// 1.3.6.1.4.1.31103.1.1004 NAME 'fedfsNfsFsl'
/// DESC 'An NFS location of a fileset'
/// SUP fedfsFsl STRUCTURAL
/// MUST (
/// fedfsNfsURI
/// $ fedfsNfsCurrency
/// $ fedfsNfsGenFlagWritable
/// $ fedfsNfsGenFlagGoing
/// $ fedfsNfsGenFlagSplit
/// $ fedfsNfsTransFlagRdma
/// $ fedfsNfsClassSimul
/// $ fedfsNfsClassHandle
/// $ fedfsNfsClassFileid
/// $ fedfsNfsClassWritever
/// $ fedfsNfsClassChange
/// $ fedfsNfsClassReaddir
/// $ fedfsNfsReadRank
/// $ fedfsNfsReadOrder
/// $ fedfsNfsWriteRank
/// $ fedfsNfsWriteOrder
/// $ fedfsNfsVarSub
/// $ fedfsNfsValidFor
/// ))
///
NSDB Operations
The operations defined by the protocol can be described as several
sub-protocols that are used by entities within a federation to
perform different roles.
The first of these sub-protocols defines how the state of an NSDB
node can be initialized and updated. The primary use of this sub-
protocol is by an administrator to add, edit, or delete filesets,
their properties, and their fileset locations.
The second of these sub-protocols defines the queries that are sent
to an NSDB node in order to perform resolution (or to find other
information about the data stored within that NSDB node) and the
responses returned by the NSDB node. The primary use of this sub-
protocol is by a fileserver in order to perform resolution, but it
may also be used by an administrator to query the state of the
system.
The first and second sub-protocols are defined as LDAP operations,
using the schema defined in the previous section. If each NSDB node
is a standard LDAP server, then, in theory, it is unnecessary to
describe the LDAP operations in detail because the operations are
ordinary LDAP operations to query and update records. However, we do
not require that an NSDB node implement a complete LDAP service.
Therefore, we define the minimum level of LDAP functionality required
to implement an NSDB node.
The NSDB sub-protocols are defined in Section 5.1 and Section 5.2.
The descriptions of LDAP messages in these sections use the LDAP Data
Interchange Format (LDIF) RFC2849. In order to differentiate
constant and variable strings in the LDIF specifications, variables
are prefixed by a $ character and use all uppercase characters. For
example, a variable named FOO would be specified as $FOO.
This document uses the term "NSDB client" to refer to an LDAP client
that uses either of the NSDB sub-protocols.
The third sub-protocol defines the queries and other requests that
are sent to a fileserver in order to get information from it or to
modify the state of the fileserver in a manner related to the
federation protocols. The primary purpose of this protocol is for an
administrator to create or delete a junction or discover related
information about a particular fileserver.
The third sub-protocol is defined as an Open Network Computing (ONC)
Remote Procedure Call (RPC) protocol. The reason for using ONC RPC
instead of LDAP is that all fileservers support ONC RPC, but some do
not support an LDAP directory server.
The ONC RPC administration protocol is defined in RFC7533.
NSDB Operations for Administrators
The admin entity initiates and controls the commands to manage
fileset and namespace information. The protocol used for
communicating between the admin entity and each NSDB node MUST be the
LDAPv3 RFC4510 protocol.
The names we assign to these operations are entirely for the purpose
of exposition in this document and are not part of the LDAP dialogs.
Create an FSN
This operation creates a new FSN in the NSDB by adding a new fedfsFsn
entry in the NSDB's LDAP directory.
A fedfsFsn entry contains a fedfsFsnUuid. The administrator chooses
the fedfsFsnUuid by the process described in Section 2.12. A
fedfsFsn entry also contains a fedfsFsnTTL. The fedfsFsnTTL is
chosen by the administrator as described in Section 2.8.3.
LDAP Request
This operation is implemented using the LDAP ADD request described by
the LDIF below.
dn: fedfsFsnUuid=$FSNUUID,$NCE
changeType: add
objectClass: fedfsFsn
fedfsFsnUuid: $FSNUUID
fedfsFsnTTL: $TTL
For example, if $FSNUUID is "e8c4761c-eb3b-4307-86fc-f702da197966",
$TTL is "300" seconds, and $NCE is "o=fedfs", the operation would be:
dn: fedfsFsnUuid=e8c4761c-eb3b-4307-86fc-f702da197966,o=fedfs
changeType: add
objectClass: fedfsFsn
fedfsFsnUuid: e8c4761c-eb3b-4307-86fc-f702da197966
fedfsFsnTTL: 300
Delete an FSN
This operation deletes an FSN by removing a fedfsFsn entry in the
NSDB's LDAP directory.
If the FSN entry being deleted has child FSL entries, this function
MUST return an error. This ensures that the NSDB will not contain
any orphaned FSL entries. A compliant LDAP implementation will meet
this requirement since Section 4.8 of RFC4511 defines the LDAP
delete operation to only be capable of removing leaf entries.
Note that the FSN delete function removes the fileset only from a
federation namespace (by removing the records for that FSN from the
NSDB node that receives this request). The fileset and its data are
not deleted. Any junction that has this FSN as its target may
continue to point to this non-existent FSN. A dangling reference may
be detected when a fileserver tries to resolve a junction that refers
to the deleted FSN.
LDAP Request
This operation is implemented using the LDAP DELETE request described
by the LDIF below.
dn: fedfsFsnUuid=$FSNUUID,$NCE
changeType: delete
For example, if $FSNUUID is "e8c4761c-eb3b-4307-86fc-f702da197966"
and $NCE is "o=fedfs", the operation would be:
dn: fedfsFsnUuid=e8c4761c-eb3b-4307-86fc-f702da197966,o=fedfs
changeType: delete
Create an FSL
This operation creates a new FSL for the given FSN by adding a new
fedfsFsl entry in the NSDB's LDAP directory.
A fedfsFsl entry contains a fedfsFslUuid and fedfsFsnUuid. The
administrator chooses the fedfsFslUuid. The process for choosing the
fedfsFslUuid is described in Section 2.12. The fedfsFsnUuid is the
UUID of the FSL's FSN.
The administrator will also set additional attributes depending on
the FSL type.
LDAP Request
This operation is implemented using the LDAP ADD request described by
the LDIF below (Note: the LDIF shows the creation of an NFS FSL.)
dn: fedfsFslUuid=$FSLUUID,fedfsFsnUuid=$FSNUUID,$NCE
changeType: add
objectClass: fedfsNfsFsl
fedfsFslUuid: $FSLUUID
fedfsFsnUuid: $FSNUUID
fedfsNfsURI: nfs://$HOST:$PORT//$PATH
fedfsNfsCurrency: $CURRENCY
fedfsNfsGenFlagWritable: $WRITABLE
fedfsNfsGenFlagGoing: $GOING
fedfsNfsGenFlagSplit: $SPLIT
fedfsNfsTransFlagRdma: $RDMA
fedfsNfsClassSimul: $CLASS_SIMUL
fedfsNfsClassHandle:$CLASS_HANDLE
fedfsNfsClassFileid:$CLASS_FILEID
fedfsNfsClassWritever:$CLASS_WRITEVER
fedfsNfsClassChange: $CLASS_CHANGE
fedfsNfsClassReaddir: $CLASS_READDIR
fedfsNfsReadRank: $READ_RANK
fedfsNfsReadOrder: $READ_ORDER
fedfsNfsWriteRank: $WRITE_RANK
fedfsNfsWriteOrder: $WRITE_ORDER
fedfsNfsVarSub: $VAR_SUB
fedfsNfsValidFor: $TIME
fedfsAnnotation: $ANNOTATION
fedfsDescr: $DESCR
For example, if $FSNUUID is "e8c4761c-eb3b-4307-86fc-f702da197966",
$FSLUUID is "ba89a802-41a9-44cf-8447-dda367590eb3", $HOST is
"server.example.com", $PORT is "20049", $PATH is stored in the file
"/tmp/fsl_path", $CURRENCY is "0" (an up-to-date copy), the FSL is
writable, but not going, split, or accessible via Remote Direct
Memory Access (RDMA), the simultaneous-use class is "1", the handle
class is "0", the fileid class is "1", the write-verifier class is
"1", the change class is "1", the readdir class is "9", the read rank
is "7", the read order is "8", the write rank is "5", the write order
is "6", variable substitution is false, $TIME is "300" seconds,
$ANNOTATION is ""foo" = "bar"", $DESC is "This is a description.",
and $NCE is "o=fedfs", the operation would be (for readability, the
DN is split into two lines):
dn: fedfsFslUuid=ba89a802-41a9-44cf-8447-dda367590eb3,
fedfsFsnUuid=e8c4761c-eb3b-4307-86fc-f702da197966,o=fedfs
changeType: add
objectClass: fedfsNfsFsl
fedfsFslUuid: ba89a802-41a9-44cf-8447-dda367590eb3
fedfsFsnUuid: e8c4761c-eb3b-4307-86fc-f702da197966
fedfsNfsURI: nfs://server.example.com:20049//tmp/fsl_path
fedfsNfsCurrency: 0
fedfsNfsGenFlagWritable: TRUE
fedfsNfsGenFlagGoing: FALSE
fedfsNfsGenFlagSplit: FALSE
fedfsNfsTransFlagRdma: FALSE
fedfsNfsClassSimul: 1
fedfsNfsClassHandle: 0
fedfsNfsClassFileid: 1
fedfsNfsClassWritever: 1
fedfsNfsClassChange: 1
fedfsNfsClassReaddir: 9
fedfsNfsReadRank: 7
fedfsNfsReadOrder: 8
fedfsNfsWriteRank: 5
fedfsNfsWriteOrder: 6
fedfsNfsVarSub: FALSE
fedfsNfsValidFor: 300
fedfsAnnotation: "foo" = "bar"
fedfsDescr: This is a description.
Selecting fedfsNfsFsl Values
The fedfsNfsFSl object class is used to describe NFSv4-accessible
filesets. For the reasons described in Section 2.8.4, administrators
SHOULD choose reasonable values for all LDAP attributes of an
NFSv4-accessible fedfsNfsFsl even though some of these LDAP
attributes are not explicitly contained in an NFSv4 fs_locations
attribute.
When the administrator is unable to choose reasonable values for the
LDAP attributes not explicitly contained in an NFSv4 fs_locations
attribute, the values in the following table are RECOMMENDED.
+-------------------------+----------+------------------------------+
| LDAP attribute | LDAP | Notes |
| | value | |
+-------------------------+----------+------------------------------+
| fedfsNfsCurrency | negative | Indicates that the server |
| | value | does not know the currency |
| | | (see Section 11.10.1 of |
| | | RFC5661). |
| fedfsNfsGenFlagWritable | FALSE | Leaving unset is not harmful |
| | | (see Section 11.10.1 of |
| | | RFC5661). |
| fedfsNfsGenFlagGoing | FALSE | NFS client will detect a |
| | | migration event if the FSL |
| | | becomes unavailable. |
| fedfsNfsGenFlagSplit | TRUE | Safe to assume that the FSL |
| | | is split. |
| fedfsNfsTransFlagRdma | TRUE | NFS client will detect if |
| | | RDMA access is available. |
| fedfsNfsClassSimul | 0 | 0 is treated as non-matching |
| | | (see Section 11.10.1 of |
| | | RFC5661). |
| fedfsNfsClassHandle | 0 | See fedfsNfsClassSimul note. |
| fedfsNfsClassFileid | 0 | See fedfsNfsClassSimul note. |
| fedfsNfsClassWritever | 0 | See fedfsNfsClassSimul note. |
| fedfsNfsClassChange | 0 | See fedfsNfsClassSimul note. |
| fedfsNfsClassReaddir | 0 | See fedfsNfsClassSimul note. |
| fedfsNfsReadRank | 0 | Highest value ensures FSL |
| | | will be tried. |
| fedfsNfsReadOrder | 0 | See fedfsNfsReadRank note. |
| fedfsNfsWriteRank | 0 | See fedfsNfsReadRank note. |
| fedfsNfsWriteOrder | 0 | See fedfsNfsReadRank note. |
| fedfsNfsVarSub | FALSE | NFSv4 does not define |
| | | variable substitution in |
| | | paths. |
| fedfsNfsValidFor | 0 | Indicates no appropriate |
| | | refetch interval (see |
| | | Section 11.10.2 of |
| | | RFC5661). |
+-------------------------+----------+------------------------------+
Delete an FSL
This operation deletes an FSL record. The admin requests the NSDB
node storing the fedfsFsl to delete it from its database. This
operation does not result in fileset data being deleted on any
fileserver.
LDAP Request
The admin sends an LDAP DELETE request to the NSDB node to remove the
FSL.
dn: fedfsFslUuid=$FSLUUID,fedfsFsnUuid=$FSNUUID,$NCE
changeType: delete
For example, if $FSNUUID is "e8c4761c-eb3b-4307-86fc-f702da197966",
$FSLUUID is "ba89a802-41a9-44cf-8447-dda367590eb3", and $NCE is
"o=fedfs", the operation would be (for readability, the DN is split
into two lines):
dn: fedfsFslUuid=ba89a802-41a9-44cf-8447-dda367590eb3,
fedfsFsnUuid=e8c4761c-eb3b-4307-86fc-f702da197966,o=fedfs
changeType: delete
Update an FSL
This operation updates the attributes of a given FSL. This command
results in a change in the attributes of the fedfsFsl at the NSDB
node maintaining this FSL. The values of the fedfsFslUuid and
fedfsFsnUuid attributes MUST NOT change during an FSL update.
LDAP Request
The admin sends an LDAP MODIFY request to the NSDB node to update the
FSL.
dn: fedfsFslUuid=$FSLUUID,fedfsFsnUuid=$FSNUUID,$NCE
changeType: modify
replace: $ATTRIBUTE-TYPE
For example, if $FSNUUID is "e8c4761c-eb3b-4307-86fc-f702da197966",
$FSLUUID is "ba89a802-41a9-44cf-8447-dda367590eb3", $NCE is
"o=fedfs", and the administrator wished to change the NFS read rank
to 10, the operation would be (for readability, the DN is split into
two lines):
dn: fedfsFslUuid=ba89a802-41a9-44cf-8447-dda367590eb3,
fedfsFsnUuid=e8c4761c-eb3b-4307-86fc-f702da197966,o=fedfs
changeType: modify
replace: fedfsNfsReadClass
fedfsNfsReadRank: 10
NSDB Operations for Fileservers
NSDB Container Entry (NCE) Enumeration
To find the NCEs for the NSDB nsdb.example.com, a fileserver would do
the following:
nce_list = empty
connect to the LDAP directory at nsdb.example.com
for each namingContext value $BAR in the root DSE
/* $BAR is a DN */
query for a fedfsNceDN value at $BAR
/*
* The RFC 4516 LDAP URL for this search would be
*
* ldap://nsdb.example.com:389/$BAR?fedfsNceDN??
* (objectClass=fedfsNsdbContainerInfo)
*
*/
if a fedfsNceDN value is found
add the value to the nce_list
Lookup FSLs for an FSN
Using an LDAP search, the fileserver can obtain all of the FSLs for a
given FSN. The FSN's fedfsFsnUuid is used as the search key. The
following examples use the LDAP Uniform Resource Identifier (URI)
format defined in RFC4516.
To obtain a list of all FSLs for $FSNUUID on the NSDB named
$NSDBNAME, the following search can be used (for readability, the URI
is split into two lines):
for each $NCE in nce_list
ldap://$NSDBNAME/fedfsFsnUuid=$FSNUUID,$NCE??one?
(objectClass=fedfsFsl)
This search is for the children of the object with DN
"fedfsFsnUuid=$FSNUUID,$NCE" with a filter for
"objectClass=fedfsFsl". The scope value of "one" restricts the
search to the entry's children (rather than the entire subtree below
the entry), and the filter ensures that only FSL entries are
returned.
For example, if $NSDBNAME is "nsdb.example.com", $FSNUUID is
"e8c4761c-eb3b-4307-86fc-f702da197966", and $NCE is "o=fedfs", the
search would be (for readability, the URI is split into three lines):
ldap://nsdb.example.com/
fedfsFsnUuid=e8c4761c-eb3b-4307-86fc-f702da197966,o=fedfs
??one?(objectClass=fedfsFsl)
The following search can be used to obtain only the NFS FSLs for
$FSNUUID on the NSDB named $NSDBNAME (for readability, the URI is
split into two lines):
for each $NCE in nce_list
ldap://$NSDBNAME/fedfsFsnUuid=$FSNUUID,$NCE??one?
(objectClass=fedfsNfsFsl)
This also searches for the children of the object with DN
"fedfsFsnUuid=$FSNUUID,$NCE", but the filter for "objectClass =
fedfsNfsFsl" restricts the results to only NFS FSLs.
For example, if $NSDBNAME is nsdb.example.com, $FSNUUID is "e8c4761c-
eb3b-4307-86fc-f702da197966", and $NCE is "o=fedfs", the search would
be (for readability, the URI is split into three lines):
ldap://nsdb.example.com/
fedfsFsnUuid=e8c4761c-eb3b-4307-86fc-f702da197966,o=fedfs
??one?(objectClass=fedfsNfsFsl)
The fileserver will generate a referral based on the set of FSLs
returned by these queries using the process described in
Section 2.8.4.
NSDB Operations and LDAP Referrals
The LDAPv3 protocol defines an LDAP referral mechanism that allows an
LDAP server to redirect an LDAP client. LDAPv3 defines two types of
LDAP referrals: the Referral type defined in Section 4.1.10 of
RFC4511 and the SearchResultReference type defined in Section 4.5.3
of RFC4511. In both cases, the LDAP referral lists one or more
URIs for services that can be used to complete the operation. In the
remainder of this document, the term "LDAP referral" is used to
indicate either of these types.
If an NSDB operation results in an LDAP referral, the NSDB client MAY
follow the LDAP referral. An NSDB client's decision to follow an
LDAP referral is implementation and configuration dependent. For
example, an NSDB client might be configured to follow only those LDAP
referrals that were received over a secure channel or only those that
target an NSDB that supports encrypted communication. If an NSDB
client chooses to follow an LDAP referral, the NSDB client MUST
process the LDAP referral and prevent looping as described in
Section 4.1.10 of RFC4511.
Security Considerations
Both the NFSv4 and LDAPv3 protocols provide security mechanisms.
When used in conjunction with the federated file system protocols
described in this document, the use of these mechanisms is
RECOMMENDED. Specifically, the use of RPCSEC_GSS RFC2203, which is
built on the Generic Security Service Application Program Interface
(GSS-API) RFC2743, is RECOMMENDED on all NFS connections between a
file-access client and fileserver. The security considerations
sections of the NFSv4.0 RFC7530 and NFSv4.1 RFC5661
specifications contain special considerations for the handling of
GETATTR operations for the fs_locations and fs_locations_info
attributes.
NSDB nodes and NSDB clients MUST implement support for TLS RFC5246,
as described in RFC4513. For all LDAP connections established by
the federated file system protocols, the use of TLS is RECOMMENDED.
If an NSDB client chooses to follow an LDAP referral, the NSDB client
SHOULD authenticate the LDAP referral's target NSDB using the target
NSDB's credentials (not the credentials of the NSDB that generated
the LDAP referral). The NSDB client SHOULD NOT follow an LDAP
referral that targets an NSDB for which it does not know the NSDB's
credentials.
Within a federation, there are two types of components an attacker
may compromise: a fileserver and an NSDB.
If an attacker compromises a fileserver, the attacker can interfere
with a file-access client's file system input/output (I/O) operations
(e.g., by returning fictitious data in the response to a read
request) or can fabricate a referral. The attacker's abilities are
the same regardless of whether or not the federation protocols are in
use. While the federation protocols do not give the attacker
additional capabilities, they are additional targets for attack. The
LDAP protocol described in Section 5.2 SHOULD be secured using the
methods described above to defeat attacks on a fileserver via this
channel.
If an attacker compromises an NSDB, the attacker will be able to
forge FSL information and thus poison the fileserver's referral
information. Therefore, an NSDB should be as secure as the
fileservers that query it. The LDAP operations described in
Section 5 SHOULD be secured using the methods described above to
defeat attacks on an NSDB via this channel.
A fileserver binds anonymously when performing NSDB operations.
Thus, the contents and distinguished names of FSN and FSL records are
required to be readable by anyone who can bind anonymously to an NSDB
service. Section 2.12 presents the security considerations in the
choice of the type of UUID used in these records.
It should be noted that the federation protocols do not directly
provide access to file system data. The federation protocols only
provide a mechanism for building a namespace. All data transfers
occur between a file-access client and fileserver just as they would
if the federation protocols were not in use. As a result, the
federation protocols do not require new user authentication and
authorization mechanisms or require a fileserver to act as a proxy
for a client.
IANA Considerations
Registry for the fedfsAnnotation Key Namespace
This document defines the fedfsAnnotation key in Section 4.2.1.6.
The fedfsAnnotation key namespace is managed by IANA. IANA has
created and now maintains a new registry entitled "FedFS Annotation
Keys". The location of this registry is under a new heading called
"Federated File System (FedFS) Parameters". The URL address is
<http://www.iana.org/assignments/fedfs-parameters>.
Future registrations are to be administered by IANA using the "First
Come First Served" policy defined in RFC5226. Registration
requests MUST include the key (a valid UTF-8 string of any length), a
brief description of the key's purpose, and an email contact for the
registration. For viewing, the registry should be sorted
lexicographically by key. There are no initial assignments for this
registry.
Registry for FedFS Object Identifiers
Using the process described in RFC2578, one of the authors was
assigned the Internet Private Enterprise Numbers range
1.3.6.1.4.1.31103.x. Within this range, the subrange
1.3.6.1.4.1.31103.1.x is permanently dedicated for use by the
federated file system protocols. Unassigned OIDs in this range MAY
be used for Private Use or Experimental Use as defined in RFC5226.
New permanent FedFS OID assignments MUST NOT be made using OIDs in
this range.
IANA has created and now maintains a new registry entitled "FedFS
Object Identifiers" for the purpose of recording the allocations of
FedFS Object Identifiers (OIDs) specified by this document. No
future allocations in this registry are allowed.
The location of this registry is under the heading "Federated File
System (FedFS) Parameters", created in Section 7.1. The URL address
is <http://www.iana.org/assignments/fedfs-parameters>.
For viewing, the registry has been sorted numerically by OID value.
The contents of the "FedFS Object Identifiers" registry are given in
Table 1.
Note: A descriptor designated below as "historic" reserves an OID
used in a past version of the NSDB protocol. Registering such OIDs
retains compatibility among existing implementations of the NSDB
protocol. This document does not otherwise refer to historic OIDs.
+---------------------------+--------------------------+-----------+
| OID | Description | Reference |
+---------------------------+--------------------------+-----------+
| 1.3.6.1.4.1.31103.1.1 | fedfsUuid | RFC 7532 |
| 1.3.6.1.4.1.31103.1.2 | fedfsNetAddr | historic |
| 1.3.6.1.4.1.31103.1.3 | fedfsNetPort | historic |
| 1.3.6.1.4.1.31103.1.4 | fedfsFsnUuid | RFC 7532 |
| 1.3.6.1.4.1.31103.1.5 | fedfsNsdbName | historic |
| 1.3.6.1.4.1.31103.1.6 | fedfsNsdbPort | historic |
| 1.3.6.1.4.1.31103.1.7 | fedfsNcePrefix | historic |
| 1.3.6.1.4.1.31103.1.8 | fedfsFslUuid | RFC 7532 |
| 1.3.6.1.4.1.31103.1.9 | fedfsFslHost | historic |
| 1.3.6.1.4.1.31103.1.10 | fedfsFslPort | historic |
| 1.3.6.1.4.1.31103.1.11 | fedfsFslTTL | historic |
| 1.3.6.1.4.1.31103.1.12 | fedfsAnnotation | RFC 7532 |
| 1.3.6.1.4.1.31103.1.13 | fedfsDescr | RFC 7532 |
| 1.3.6.1.4.1.31103.1.14 | fedfsNceDN | RFC 7532 |
| 1.3.6.1.4.1.31103.1.15 | fedfsFsnTTL | RFC 7532 |
| 1.3.6.1.4.1.31103.1.100 | fedfsNfsPath | historic |
| 1.3.6.1.4.1.31103.1.101 | fedfsNfsMajorVer | historic |
| 1.3.6.1.4.1.31103.1.102 | fedfsNfsMinorVer | historic |
| 1.3.6.1.4.1.31103.1.103 | fedfsNfsCurrency | RFC 7532 |
| 1.3.6.1.4.1.31103.1.104 | fedfsNfsGenFlagWritable | RFC 7532 |
| 1.3.6.1.4.1.31103.1.105 | fedfsNfsGenFlagGoing | RFC 7532 |
| 1.3.6.1.4.1.31103.1.106 | fedfsNfsGenFlagSplit | RFC 7532 |
| 1.3.6.1.4.1.31103.1.107 | fedfsNfsTransFlagRdma | RFC 7532 |
| 1.3.6.1.4.1.31103.1.108 | fedfsNfsClassSimul | RFC 7532 |
| 1.3.6.1.4.1.31103.1.109 | fedfsNfsClassHandle | RFC 7532 |
| 1.3.6.1.4.1.31103.1.110 | fedfsNfsClassFileid | RFC 7532 |
| 1.3.6.1.4.1.31103.1.111 | fedfsNfsClassWritever | RFC 7532 |
| 1.3.6.1.4.1.31103.1.112 | fedfsNfsClassChange | RFC 7532 |
| 1.3.6.1.4.1.31103.1.113 | fedfsNfsClassReaddir | RFC 7532 |
| 1.3.6.1.4.1.31103.1.114 | fedfsNfsReadRank | RFC 7532 |
| 1.3.6.1.4.1.31103.1.115 | fedfsNfsReadOrder | RFC 7532 |
| 1.3.6.1.4.1.31103.1.116 | fedfsNfsWriteRank | RFC 7532 |
| 1.3.6.1.4.1.31103.1.117 | fedfsNfsWriteOrder | RFC 7532 |
| 1.3.6.1.4.1.31103.1.118 | fedfsNfsVarSub | RFC 7532 |
| 1.3.6.1.4.1.31103.1.119 | fedfsNfsValidFor | RFC 7532 |
| 1.3.6.1.4.1.31103.1.120 | fedfsNfsURI | RFC 7532 |
| 1.3.6.1.4.1.31103.1.1001 | fedfsNsdbContainerInfo | RFC 7532 |
| 1.3.6.1.4.1.31103.1.1002 | fedfsFsn | RFC 7532 |
| 1.3.6.1.4.1.31103.1.1003 | fedfsFsl | RFC 7532 |
| 1.3.6.1.4.1.31103.1.1004 | fedfsNfsFsl | RFC 7532 |
+---------------------------+--------------------------+-----------+
Table 1
LDAP Descriptor Registration
In accordance with Sections 3.4 and 4 of RFC4520, the object
identifier descriptors defined in this document (listed below) have
been registered via the Expert Review process.
Subject: Request for LDAP Descriptor Registration
Person & email address to contact for further information: See
"Author/Change Controller"
Specification: RFC 7532
Author/Change Controller: IESG ([email protected])
Object Identifier: 1.3.6.1.4.1.31103.1.1
Descriptor (short name): fedfsUuid
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.2
Descriptor (short name): fedfsNetAddr
Usage: attribute type (historic)
Object Identifier: 1.3.6.1.4.1.31103.1.3
Descriptor (short name): fedfsNetPort
Usage: attribute type (historic)
Object Identifier: 1.3.6.1.4.1.31103.1.4
Descriptor (short name): fedfsFsnUuid
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.5
Descriptor (short name): fedfsNsdbName
Usage: attribute type (historic)
Object Identifier: 1.3.6.1.4.1.31103.1.6
Descriptor (short name): fedfsNsdbPort
Usage: attribute type (historic)
Object Identifier: 1.3.6.1.4.1.31103.1.7
Descriptor (short name): fedfsNcePrefix
Usage: attribute type (historic)
Object Identifier: 1.3.6.1.4.1.31103.1.8
Descriptor (short name): fedfsFslUuid
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.9
Descriptor (short name): fedfsFslHost
Usage: attribute type (historic)
Object Identifier: 1.3.6.1.4.1.31103.1.10
Descriptor (short name): fedfsFslPort
Usage: attribute type (historic)
Object Identifier: 1.3.6.1.4.1.31103.1.11
Descriptor (short name): fedfsFslTTL
Usage: attribute type (historic)
Object Identifier: 1.3.6.1.4.1.31103.1.12
Descriptor (short name): fedfsAnnotation
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.13
Descriptor (short name): fedfsDescr
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.14
Descriptor (short name): fedfsNceDN
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.15
Descriptor (short name): fedfsFsnTTL
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.100
Descriptor (short name): fedfsNfsPath
Usage: attribute type (historic)
Object Identifier: 1.3.6.1.4.1.31103.1.101
Descriptor (short name): fedfsNfsMajorVer
Usage: attribute type (historic)
Object Identifier: 1.3.6.1.4.1.31103.1.102
Descriptor (short name): fedfsNfsMinorVer
Usage: attribute type (historic)
Object Identifier: 1.3.6.1.4.1.31103.1.103
Descriptor (short name): fedfsNfsCurrency
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.104
Descriptor (short name): fedfsNfsGenFlagWritable
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.105
Descriptor (short name): fedfsNfsGenFlagGoing
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.106
Descriptor (short name): fedfsNfsGenFlagSplit
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.107
Descriptor (short name): fedfsNfsTransFlagRdma
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.108
Descriptor (short name): fedfsNfsClassSimul
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.109
Descriptor (short name): fedfsNfsClassHandle
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.110
Descriptor (short name): fedfsNfsClassFileid
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.111
Descriptor (short name): fedfsNfsClassWritever
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.112
Descriptor (short name): fedfsNfsClassChange
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.113
Descriptor (short name): fedfsNfsClassReaddir
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.114
Descriptor (short name): fedfsNfsReadRank
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.115
Descriptor (short name): fedfsNfsReadOrder
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.116
Descriptor (short name): fedfsNfsWriteRank
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.117
Descriptor (short name): fedfsNfsWriteOrder
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.118
Descriptor (short name): fedfsNfsVarSub
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.119
Descriptor (short name): fedfsNfsValidFor
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.120
Descriptor (short name): fedfsNfsURI
Usage: attribute type
Object Identifier: 1.3.6.1.4.1.31103.1.1001
Descriptor (short name): fedfsNsdbContainerInfo
Usage: object class
Object Identifier: 1.3.6.1.4.1.31103.1.1002
Descriptor (short name): fedfsFsn
Usage: object class
Object Identifier: 1.3.6.1.4.1.31103.1.1003
Descriptor (short name): fedfsFsl
Usage: object class
Object Identifier: 1.3.6.1.4.1.31103.1.1004
Descriptor (short name): fedfsNfsFsl
Usage: object class
Glossary
Administrator: A user with the necessary authority to initiate
administrative tasks on one or more servers.
Admin Entity: A server or agent that administers a collection of
fileservers and persistently stores the namespace information.
File-Access Client: Standard off-the-shelf, network-attached storage
(NAS) client software that communicates with fileservers using a
standard file-access protocol.
Federation: A set of fileserver collections and singleton
fileservers that use a common set of interfaces and protocols in
order to provide to file-access clients a federated namespace
accessible through a file system access protocol.
Fileserver: A server that stores physical fileset data or refers
file-access clients to other fileservers. A fileserver provides
access to its shared file system data via a file-access protocol.
Fileset: The abstraction of a set of files and the directory tree
that contains them. A fileset is the fundamental unit of data
management in the federation.
Note that all files within a fileset are descendants of one
directory and that filesets do not span file systems.
File System: A self-contained unit of export for a fileserver and
the mechanism used to implement filesets. The fileset does not
need to be rooted at the root of the file system, nor at the
export point for the file system.
A single file system MAY implement more than one fileset, if the
file-access protocol and the fileserver permit this.
File-Access Protocol: A network file system access protocol such as
NFSv3 RFC1813, NFSv4 RFC7530, or CIFS (Common Internet File
System) [MS-SMB] [MS-SMB2] [MS-CIFS].
FSL (Fileset Location): The location of the implementation of a
fileset at a particular moment in time. An FSL MUST be something
that can be translated into a protocol-specific description of a
resource that a file-access client can access directly, such as an
fs_locations attribute (for NFSv4) or a share name (for CIFS).
FSN (Fileset Name): A platform-independent and globally unique name
for a fileset. Two FSLs that implement replicas of the same
fileset MUST have the same FSN, and if a fileset is migrated from
one location to another, the FSN of that fileset MUST remain the
same.
Junction: A file system object used to link a directory name in the
current fileset with an object within another fileset. The
server-side "link" from a leaf node in one fileset to the root of
another fileset.
Namespace: A filename/directory tree that a sufficiently authorized
file-access client can observe.
NSDB (Namespace Database) Service: A service that maps FSNs to FSLs.
The NSDB may also be used to store other information, such as
annotations for these mappings and their components.
NSDB Node: The name or location of a server that implements part of
the NSDB service and is responsible for keeping track of the FSLs
(and related information) that implement a given partition of the
FSNs.
Referral: A server response to a file-access client access that
directs the client to evaluate the current object as a reference
to an object at a different location (specified by an FSL) in
another fileset and possibly hosted on another fileserver. The
client re-attempts the access to the object at the new location.
Replica: A redundant implementation of a fileset. Each replica
shares the same FSN but has a different FSL.
Replicas may be used to increase availability or performance.
Updates to replicas of the same fileset MUST appear to occur in
the same order; therefore, each replica is self-consistent at any
moment.
We do not assume that updates to each replica occur
simultaneously. If a replica is offline or unreachable, the other
replicas may be updated.
Server Collection: A set of fileservers administered as a unit. A
server collection may be administered with vendor-specific
software.
The namespace provided by a server collection could be part of the
federated namespace.
Singleton Server: A server collection containing only one server; a
stand-alone fileserver.
References
Normative References
RFC2079 Smith, M., "Definition of an X.500 Attribute Type and an
Object Class to Hold Uniform Resource Identifiers (URIs)",
RFC 2079, January 1997,
<http://www.rfc-editor.org/info/rfc2079>.
RFC2119 Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
RFC2203 Eisler, M., Chiu, A., and L. Ling, "RPCSEC_GSS Protocol
Specification", RFC 2203, September 1997,
<http://www.rfc-editor.org/info/rfc2203>.
RFC2578 McCloghrie, K., Ed., Perkins, D., Ed., and J.
Schoenwaelder, Ed., "Structure of Management Information
Version 2 (SMIv2)", STD 58, RFC 2578, April 1999,
<http://www.rfc-editor.org/info/rfc2578>.
RFC2743 Linn, J., "Generic Security Service Application Program
Interface Version 2, Update 1", RFC 2743, January 2000,
<http://www.rfc-editor.org/info/rfc2743>.
RFC2849 Good, G., "The LDAP Data Interchange Format (LDIF) -
Technical Specification", RFC 2849, June 2000,
<http://www.rfc-editor.org/info/rfc2849>.
RFC3629 Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, November 2003,
<http://www.rfc-editor.org/info/rfc3629>.
RFC3986 Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, RFC
3986, January 2005,
<http://www.rfc-editor.org/info/rfc3986>.
RFC4122 Leach, P., Mealling, M., and R. Salz, "A Universally
Unique IDentifier (UUID) URN Namespace", RFC 4122, July
2005, <http://www.rfc-editor.org/info/rfc4122>.
RFC4510 Zeilenga, K., Ed., "Lightweight Directory Access Protocol
(LDAP): Technical Specification Road Map", RFC 4510, June
2006, <http://www.rfc-editor.org/info/rfc4510>.
RFC4511 Sermersheim, J., Ed., "Lightweight Directory Access
Protocol (LDAP): The Protocol", RFC 4511, June 2006,
<http://www.rfc-editor.org/info/rfc4511>.
RFC4512 Zeilenga, K., Ed., "Lightweight Directory Access Protocol
(LDAP): Directory Information Models", RFC 4512, June
2006, <http://www.rfc-editor.org/info/rfc4512>.
RFC4513 Harrison, R., Ed., "Lightweight Directory Access Protocol
(LDAP): Authentication Methods and Security Mechanisms",
RFC 4513, June 2006,
<http://www.rfc-editor.org/info/rfc4513>.
RFC4516 Smith, M., Ed. and T. Howes, "Lightweight Directory Access
Protocol (LDAP): Uniform Resource Locator", RFC 4516, June
2006, <http://www.rfc-editor.org/info/rfc4516>.
RFC4517 Legg, S., Ed., "Lightweight Directory Access Protocol
(LDAP): Syntaxes and Matching Rules", RFC 4517, June 2006,
<http://www.rfc-editor.org/info/rfc4517>.
RFC4519 Sciberras, A., Ed., "Lightweight Directory Access Protocol
(LDAP): Schema for User Applications", RFC 4519, June
2006, <http://www.rfc-editor.org/info/rfc4519>.
RFC4520 Zeilenga, K., "Internet Assigned Numbers Authority (IANA)
Considerations for the Lightweight Directory Access
Protocol (LDAP)", BCP 64, RFC 4520, June 2006,
<http://www.rfc-editor.org/info/rfc4520>.
RFC4530 Zeilenga, K., "Lightweight Directory Access Protocol
(LDAP) entryUUID Operational Attribute", RFC 4530, June
2006, <http://www.rfc-editor.org/info/rfc4530>.
RFC5226 Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008, <http://www.rfc-editor.org/info/rfc5226>.
RFC5234 Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, January 2008,
<http://www.rfc-editor.org/info/rfc5234>.
RFC5246 Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008,
<http://www.rfc-editor.org/info/rfc5246>.
RFC5661 Shepler, S., Ed., Eisler, M., Ed., and D. Noveck, Ed.,
"Network File System (NFS) Version 4 Minor Version 1
Protocol", RFC 5661, January 2010,
<http://www.rfc-editor.org/info/rfc5661>.
RFC7530 Haynes, T., Ed. and D. Noveck, Ed., "Network File System
(NFS) Version 4 Protocol", RFC 7530, March 2015,
<http://www.rfc-editor.org/info/rfc7530>.
Informative References
[AFS] Howard, J., "An Overview of the Andrew File System",
Proceedings of the USENIX Winter Technical Conference ,
1988.
[MS-CIFS] Microsoft Corporation, "Common Internet File System (CIFS)
Protocol Specification", MS-CIFS 24.0, May 2014.
[MS-SMB] Microsoft Corporation, "Server Message Block (SMB)
Protocol Specification", MS-SMB 43.0, May 2014.
[MS-SMB2] Microsoft Corporation, "Server Message Block (SMB) Version
2 Protocol Specification", MS-SMB2 46.0, May 2014.
RFC1813 Callaghan, B., Pawlowski, B., and P. Staubach, "NFS
Version 3 Protocol Specification", RFC 1813, June 1995,
<http://www.rfc-editor.org/info/rfc1813>.
RFC2224 Callaghan, B., "NFS URL Scheme", RFC 2224, October 1997,
<http://www.rfc-editor.org/info/rfc2224>.
RFC3254 Alvestrand, H., "Definitions for talking about
directories", RFC 3254, April 2002,
<http://www.rfc-editor.org/info/rfc3254>.
RFC5662 Shepler, S., Ed., Eisler, M., Ed., and D. Noveck, Ed.,
"Network File System (NFS) Version 4 Minor Version 1
External Data Representation Standard (XDR) Description",
RFC 5662, January 2010,
<http://www.rfc-editor.org/info/rfc5662>.
RFC5716 Lentini, J., Everhart, C., Ellard, D., Tewari, R., and M.
Naik, "Requirements for Federated File Systems", RFC 5716,
January 2010, <http://www.rfc-editor.org/info/rfc5716>.
RFC6641 Everhart, C., Adamson, W., and J. Zhang, "Using DNS SRV to
Specify a Global File Namespace with NFS Version 4", RFC
6641, June 2012, <http://www.rfc-editor.org/info/rfc6641>.
RFC7533 Lentini, J., Tewari, R., and C. Lever, Ed.,
"Administration Protocol for Federated File Systems", RFC
7533, March 2015,
<http://www.rfc-editor.org/info/rfc7533>.
Acknowledgments
Daniel Ellard contributed significant parts of this document.
The authors and editor would like to thank Craig Everhart and Manoj
Naik, who were co-authors of an earlier draft version of this
document. In addition, we would like to thank Andy Adamson, Paul
Lemahieu, Mario Wurzl, and Robert Thurlow for helping to author this
document.
We would like to thank George Amvrosiadis, Trond Myklebust, Howard
Chu, and Nicolas Williams for their comments and review.
The editor gratefully acknowledges the IESG reviewers, whose
constructive comments helped make this a much stronger document.
Finally, we would like to thank Andy Adamson, Rob Thurlow, and Tom
Haynes for helping to get this document out the door.
The extract.sh shell script and formatting conventions were first
described by the authors of the NFSv4.1 XDR specification RFC5662.
Authors' Addresses
James Lentini
NetApp
1601 Trapelo Rd, Suite 16
Waltham, MA 02451
United States
Phone: +1 781-768-5359
EMail: [email protected]
Renu Tewari
IBM Almaden
650 Harry Rd
San Jose, CA 95120
United States
EMail: [email protected]
Charles Lever (editor)
Oracle Corporation
1015 Granger Avenue
Ann Arbor, MI 48104
United States
Phone: +1 248-614-5091
EMail: [email protected]