NETCONF B. Lengyel
Internet-Draft Ericsson
Intended status: Standards Track M. Bjorklund
Expires: June 11, 2009 Tail-f Systems
December 08, 2008
Partial Lock RPC for NETCONF
draft-ietf-netconf-partial-lock-05
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Copyright Notice
Copyright (C) The IETF Trust (2008).
Abstract
The NETCONF protocol defines the lock and unlock RPCs, used to lock
entire configuration datastores. In some situations, a way to lock
only parts of a configuration datastore is required. This document
defines a capability-based extension to the NETCONF protocol for
locking portions of a configuration datastore.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Definition of Terms . . . . . . . . . . . . . . . . . . . 3
2. Partial Locking Capability . . . . . . . . . . . . . . . . . . 3
2.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1.1. Usage Scenarios . . . . . . . . . . . . . . . . . . . 4
2.2. Dependencies . . . . . . . . . . . . . . . . . . . . . . . 5
2.3. Capability Identifier . . . . . . . . . . . . . . . . . . 5
2.4. New Operations . . . . . . . . . . . . . . . . . . . . . . 5
2.4.1. <partial-lock> . . . . . . . . . . . . . . . . . . . . 6
2.4.2. <partial-unlock> . . . . . . . . . . . . . . . . . . . 10
2.5. Modifications to Existing Operations . . . . . . . . . . . 11
2.6. Interactions with Other Capabilities . . . . . . . . . . . 12
2.6.1. Candidate Configuration Capability . . . . . . . . . . 12
2.6.2. Confirmed Commit Capability . . . . . . . . . . . . . 12
2.6.3. Distinct Startup Capability . . . . . . . . . . . . . 12
3. Security Considerations . . . . . . . . . . . . . . . . . . . 12
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
5. Appendix A - XML Schema for Partial Locking (normative) . . 14
6. Appendix B - YANG Module for Partial Locking
(non-normative) . . . . . . . . . . . . . . . . . . . . . . . 18
7. Appendix C - Change Log . . . . . . . . . . . . . . . . . . 21
7.1. 04-05 . . . . . . . . . . . . . . . . . . . . . . . . . . 21
7.2. 03-04 . . . . . . . . . . . . . . . . . . . . . . . . . . 21
7.3. 02-03 . . . . . . . . . . . . . . . . . . . . . . . . . . 21
7.4. 01-02 . . . . . . . . . . . . . . . . . . . . . . . . . . 21
7.5. 00-01 . . . . . . . . . . . . . . . . . . . . . . . . . . 22
7.6. -00 . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 23
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 24
9.1. Normative References . . . . . . . . . . . . . . . . . . . 24
9.2. Informative References . . . . . . . . . . . . . . . . . . 24
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 25
Intellectual Property and Copyright Statements . . . . . . . . . . 26
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1. Introduction
The [NETCONF] protocol describes the lock and unlock operations that
operate on entire configuration datastores. Often, multiple
management sessions need to be able to modify the configuration of a
managed device in parallel. In these cases, locking only parts of a
configuration datastore is needed. This document defines a
capability based extension to the NETCONF protocol to support partial
locking of NETCONF datastores using a mechanism based on the existing
XPath filtering mechanisms.
1.1. Definition of Terms
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14, [RFC2119].
Additionally the following terms are defined:
o Instance Identifier: an XPath expression identifying a specific
node in the conceptual XML datastore. It contains an absolute
path expression in abbreviated syntax, where predicates are used
only to specify values for nodes defined as keys to distinguish
multiple instances.
o Scope of the lock: initially the set of nodes returned by the
XPath expressions in a successful partial-lock operation. The set
might be modified if some of the nodes are deleted.
o Protected area: the set of nodes that are protected from
modification by the lock. This consist of nodes in the scope of
the lock and nodes in subtrees under them.
2. Partial Locking Capability
2.1. Overview
The :partial-lock capability indicates that the device supports the
locking of its configuration with a more limited scope than a
complete configuration datastore. The scope to be locked is
specified by using restricted or full XPath expressions. Partial
locking only affects configuration data.
The system MUST ensure that configuration resources covered by the
lock are not modified by other NETCONF or non-NETCONF management
operations such as SNMP and the CLI.
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The duration of the partial lock begins when the partial lock is
granted and lasts until (1) either the corresponding partial-unlock
operation succeeds or (2) the NETCONF session terminates.
A NETCONF session MAY have multiple parts of one or more datastores
(running, candidate, startup) locked using partial lock operations.
The <partial-lock> operation returns a lock-id to identify each
successfully acquired lock.
2.1.1. Usage Scenarios
In the following we describe a few scenarios for partial locking.
While scenarios using the running datastore are seen as the most
important, as an example a scenario involving the candidate datastore
is also presented. Besides the three described here, there are many
other usage scenarios possible.
2.1.1.1. Multiple managers handling the writable running datastore
Multiple managers are handling the same NETCONF agent simultaneously.
The agent is handled via the writable running datastore. Each
manager has his or her own task, which might involve the modification
of overlapping sections of the datastore.
After collecting and analyzing input and preparing the NETCONF
operations off-line, the manager locks the areas that are important
for his task using one single <partial-lock> operation. The manager
executes a number of <edit-config> operations to modify the
configuration, then releases the partial-lock. The lock should be
held for only a short time (seconds rather then minutes). The
manager should collect all human input before locking anything. As
each manager locks only a part of the data model, usually multiple
operators can execute the <edit-config> operations simultaneously.
2.1.1.2. Multiple managers handling the writable running datastore,
distinct management areas
Multiple managers are handling the same NETCONF agent simultaneously.
The agent is handled via the writable running datastore. The agent's
data model contains a number of well defined separate areas that can
be configured without impacting other areas. An example can be a
server with multiple applications running on it, or a number of a
network elements with a common NETCONF agent for management.
Each manager has his or her own task, which does not involve the
modification of overlapping sections of the datastore.
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The manager locks his area with a <partial-lock> operation, uses a
number of <edit-config> commands to modify it, later releases the
lock. As each manager has his functional area assigned to him, and
he locks only that area, multiple managers can edit the configuration
simultaneously. Locks can be held for extended periods (minutes,
hours), as this will not hinder other managers.
This scenario assumes, that the global lock operation from [NETCONF]
is not used.
2.1.1.3. Multiple managers handling the candidate datastore in a semi-
coordinated work mode
Multiple managers are handling the same NETCONF agent simultaneously.
The agent is handled via the candidate datastore. Each manager has
his or her own task which might involve the modification of
overlapping sections of the datastore.
After collecting and analyzing input and preparing the NETCONF
operations off-line, the manager locks the areas that are important
for his task using one single <partial-lock> operation in both the
candidate and the running datastore. He executes a number of <edit-
config> operations to modify the configuration, then releases the
partial-lock. The lock should be held for only a short time (seconds
rather then minutes).
Operators coordinate with each other. When all of them finish their
tasks one of them orders commit. If any of the operators are still
working, and holds a lock, the commit will fail, and will need to be
repeated after all managers finish.
2.2. Dependencies
The device MUST support restricted XPath expressions in the select
element, as described in Section 2.4.1. Optionally, if the :xpath
capability is also supported (as defined in [NETCONF] chapter 8.9.
XPath Capability), the device MUST also support using any XPath 1.0
expression in the select element.
2.3. Capability Identifier
urn:ietf:params:netconf:capability:partial-lock:1.0
2.4. New Operations
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2.4.1. <partial-lock>
The <partial-lock> operation allows the client to lock a portion of
one or more datastores. The portion to lock is specified with XPath
expressions in the "select" elements and the list of datastores in
the "target" elements in the <partial-lock> operation. Each XPath
expression MUST return a node set.
When a NETCONF session holds a lock on a node, no other session or
non-NETCONF mechanism of the system can change that node or any node
in the hierarchy of nodes beneath it.
Locking a node protects the node itself and the complete subtree
under the node from modification by others. The set of locked nodes
is called the scope of the lock, while all the locked nodes and the
nodes in the subtrees under them make up the protected area.
In some situations it is desirable that the same set of nodes are
locked in more than one datastore. For example, if an interface is
configured in the candidate datastore, it is dangerous for it to be
configured by someone else in a possibly conflicting manner in the
running datastore. For this reason <partial-lock> allows the locking
of the same sections of the management data in multiple datastores.
The XPath expressions are evaluated only once at lock time.
Thereafter, the scope of the lock is maintained as a set of nodes,
i.e. the returned nodeset, and not by the XPath expression. If the
configuration data is later altered in a way that would make the
original XPath expressions evaluate to a different set of nodes, this
does not affect the scope of the partial lock.
Let's say the agent's data model includes a list of users. If the
XPath expression in the partial lock operation covers all users at
locking, the scope of the lock will be maintained as the list of
"user" nodes at the time when the lock was granted. If someone later
creates a new user, this new user will not be included in the locked-
nodes list created previously, the new user will not be locked.
A <partial-lock> operation MUST be handled atomically by the NETCONF
server. The server either locks all requested parts of the
datastore(s) or none. If during the <partial-lock> operation one of
the requested parts cannot be locked, the server MUST unlock all
parts that have already been locked during that operation.
If a node in the scope of the lock is deleted, it is removed from the
scope of the lock, so any other session or non-NETCONF mechanism can
recreate it. If all nodes in the scope of the lock are deleted, the
lock will still be present. However, its scope will become empty
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(since the lock will not cover any nodes).
A NETCONF server MUST be able to grant multiple simultaneous partial
locks to a single NETCONF session. If the protected area of the
individual locks overlaps, nodes in the common area MUST be protected
until all of the locks are released.
A partial lock operation MUST fail if:
o Any NETCONF session (including the current session) owns the
global lock on any target datastore.
o Any part of the area to be protected is already locked (or
protected by partial locking) by another management session,
including other NETCONF sessions using <partial-lock> or any other
non-NETCONF management method.
o The NETCONF server implements access control, and the locking user
does not have sufficient access rights. The exact handling of
access rights is outside the scope of this document, but it is
assumed that there is an access control system that MAY deny or
allow the partial lock operation.
The <partial-lock> operation is designed for simplicity, so when a
partial lock is executed you get what you asked for: a set of nodes
that are locked for writing. As a consequence users must observe the
following:
o Locking does not affect read operations.
o If part of a datastore is locked, this has no effect on any
unlocked parts of the datastore. If this is a problem (e.g.,
changes depend on data values or nodes outside the protected part
of the datastore), these nodes should be included in the protected
area of the lock.
o Configuration data can be edited both inside and outside the
protected area of a lock. It is the responsibility of the NETCONF
client application to lock all relevant parts of a datastore that
are crucial for a specific management action.
Note: The <partial-lock> operation does not modify the global <lock>
operation defined in the base NETCONF Protocol [NETCONF]. If part of
a datastore is already locked by <partial-lock>, then a global lock
for that datastore MUST fail even if the global lock is requested by
the NETCONF session that owns the partial lock.
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2.4.1.1. Parameters, Result, Examples
Parameters:
target: Name of one or more configuration datastores of which a part
shall be locked. If multiple datastores are specified the same
select parameter(s) are evaluated for each of them.
select: One or more 'select' elements, each containing an XPath
expression. The XPath expression is evaluated in a context where
the context node is the root of the server's conceptual data
model, and the set of namespace declarations are those in scope
on the select element.
Each select expression is evaluated for each targeted datastore.
The nodes returned from the select expressions are reported in
the rpc-reply message.
Note that if some of the requested nodes exist only in some of
the targeted datastores, the lock is granted on different nodes
in different datastores.
Each select expression MUST return a node set, and at least one
of the node sets for one of the specified datastores MUST be non-
empty.
If the device supports the :xpath capability, any valid XPath 1.0
expression can be used. If the device does not support the
:xpath capability, the XPath expression MUST be limited to an
Instance Identifier expression. An Instance Identifier is an
absolute path expression in abbreviated syntax, where predicates
are used only to specify values for nodes defined as keys to
distinguish multiple instances.
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Example: Lock virtual router 1 and interface eth1
<nc:rpc
xmlns="urn:ietf:params:xml:ns:netconf:partial-lock:1.0"
xmlns:nc="urn:ietf:params:xml:ns:netconf:base:1.0"
message-id="135">
<partial-lock>
<target>
<running/>
</target>
<select xmlns:rte="http://example.com/ns/route">
/rte:routing/rte:virtualRouter[rte:routerName='router1']
</select>
<select xmlns:if="http://example.com/ns/interface">
/if:interfaces/if:interface[if:id='eth1']
</select>
</partial-lock>
</nc:rpc>
<nc:rpc-reply
xmlns:nc="urn:ietf:params:xml:ns:netconf:base:1.0"
xmlns="urn:ietf:params:xml:ns:netconf:partial-lock:1.0"
message-id="135">
<lock-id>127</lock-id>
<running>
<locked-node xmlns:rte="http://example.com/ns/route">
/rte:routing/rte:virtualRouter[rte:routerName='router1']
</locked-node>
<locked-node xmlns:if="http://example.com/ns/interface">
/if:interfaces/if:interface[if:id='eth1']
</locked-node>
</running>
</nc:rpc-reply>
Positive Response:
If the device was able to satisfy the request, an <rpc-reply> is sent
with a <lock-id> element (lock identifier) in the <rpc-reply>
element. A list of locked nodes per datastore is also returned in
Instance Identifier format.
Negative Response:
If a lock is already held by another session on any node within the
subtrees to be locked, the <error-tag> element is 'lock-denied' and
the <error-info> element includes the <session-id> of the lock owner.
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If the lock is held by a non-NETCONF session, a <session-id> of 0
(zero) is included. If needed the returned session-id may be used to
<kill-session> the NETCONF session holding the lock. The same error
response is returned if the requesting session already holds the
(global) lock for the same datastore.
If all the select expressions return an empty node set, the <error-
tag> is 'operation-failed', and the <error-app-tag> is 'no-matches'.
If any select expression returns something other than a node set, the
<error-tag> is 'invalid-value', the <error-app-tag> is 'not-a-node-
set'.
If the :xpath capability is not supported and the XPath expression is
not an Instance Identifier, the <error-tag> is 'invalid-value', the
<error-app-tag> is 'invalid-lock-specification'.
If access control denies the partial lock, the <error-tag> is
'access-denied'.
2.4.1.2. Reserving nodes for future editing
Partial lock cannot be used to lock non-existent nodes, which would
effectively attempt to reserve them for future use. To guarantee
that a node cannot be created by some other session, the parent node
should be locked, the top level node of the new section created, and
then locked with another <partial-lock> operation. After this, the
lock on the parent node should be removed.
2.4.1.3. Deadlock Avoidance
As with most locking systems, it is possible that two management
sessions trying to lock different parts of the configuration could
become dead-locked. To avoid this situation, clients should lock
everything they need in one operation. If locking fails, the client
should back-off, release any previously acquired locks, and retry the
procedure after waiting some randomized time interval.
2.4.2. <partial-unlock>
The operation unlocks the parts of the datastores that were
previously locked using <partial-lock> during the same session.
Parameters:
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lock-id: Identity of the lock to be unlocked. This lock-id MUST
have been received as a response to a lock request by the manager
during the current session, and MUST NOT have been sent in a
previous unlock request.
Example: Unlock a previously created lock
<nc:rpc xmlns="urn:ietf:params:xml:ns:netconf:partial-lock:1.0"
xmlns:nc="urn:ietf:params:xml:ns:netconf:base:1.0"
message-id="136">
<partial-unlock>
<lock-id>127</lock-id>
</partial-unlock>
</nc:rpc>
Positive Response:
If the device was able to satisfy the request, an <rpc-reply> is sent
that contains an <ok> element. A positive response MUST be sent even
if all of the locked parts of the datastore(s) have already been
deleted.
Negative Response:
If the <lock-id> parameter does not identify a lock which is owned by
the session, an 'invalid-value' error is returned.
2.5. Modifications to Existing Operations
A successful partial lock will cause a subsequent operation to fail
if that attempts to modify nodes in the protected area of the lock
and is executed in a NETCONF session other than the session that has
been granted the lock. The <error-tag> 'in-use' and the <error-app-
tag> 'locked' is returned. All operations that modify the datastore
are affected, including: <edit-config>, <copy-config>, <delete-
config>, <commit> and <discard-changes>. If a datastore contains
nodes locked by partial lock, this will cause the (global) <lock>
operation to fail. The <error-tag> element 'lock-denied' and an
<error-info> element including the <session-id> of the lock owner
will be returned. If the lock is held by a non-NETCONF session, a
<session-id> of 0 (zero) is returned.
All of these operations are affected only if they are targeting the
same datastore.
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2.6. Interactions with Other Capabilities
2.6.1. Candidate Configuration Capability
Partial locking of the candidate datastore can only be done if the
:candidate capability is supported by the device. Partial locking of
the candidate datastore does not depend on whether the datastore was
modified or not.
2.6.2. Confirmed Commit Capability
If:
o a partial lock is requested for the running datastore, and
o the NETCONF server implements the :confirmed-commit capability,
and
o there was a recent confirmed <commit> operation where the
confirming <commit> operation has not been received
then the lock MUST be denied, because if the confirmation does not
arrive, the running datastore MUST be rolled back to its state before
the commit. The NETCONF server might therefore need to modify the
configuration.
In this case the <error-tag> 'in-use' and the <error-app-tag>
'outstanding-confirmed-commit' is returned.
2.6.3. Distinct Startup Capability
Partial locking of the startup datastore can only be done if the
:startup capability is supported by the device.
3. Security Considerations
The same considerations are relevant as for the base NETCONF Protocol
[NETCONF]. It is assumed that the <partial-lock> and <partial-
unlock> RPCs are only allowed for an authenticated user after passing
some access control mechanism.
A lock (either a partial lock or a global lock) might prevent other
users from configuring the system. The following mechanisms are in
place to prevent the misuse of this possibility:
Only an authenticated and authorized user can request a partial
lock.
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The partial lock is automatically released when a session is
terminated regardless of how the session ends.
The <kill-session> operation makes it possible to terminate other
users's sessions.
The NETCONF server may log partial lock requests in an audit
trail.
A lock that is hung for some reason (e.g., a broken TCP connection
that the server has not yet recognised) can be released using another
NETCONF session by explicitly killing the session owning that lock
using the <kill-session> operation.
Partial locking is NOT an authorization mechanism; it SHOULD NOT be
used to provide security or access control. Partial locking SHOULD
only be used as a mechanism for providing consistency when multiple
managers are trying to configure the node. It is vital that users
easily understand the exact scope of a lock. This is why the scope
is determined when granting a lock and is not modified thereafter.
4. IANA Considerations
This document registers two URIs for the NETCONF XML namespace in the
IETF XML registry [RFC3688]. Note that the capability URN is
compliant to [NETCONF] section 10.3.
+---------------+---------------------------------------------------+
| Index | Capability Identifier |
+---------------+---------------------------------------------------+
| :partial-lock | urn:ietf:params:netconf:capability:partial-lock:1 |
| | .0 |
+---------------+---------------------------------------------------+
URI: urn:ietf:params:xml:ns:netconf:partial-lock:1.0
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
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5. Appendix A - XML Schema for Partial Locking (normative)
The following XML Schema defines the <partial-lock> and <partial-
unlock> operations:
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns="urn:ietf:params:xml:ns:netconf:partial-lock:1.0"
xmlns:nc="urn:ietf:params:xml:ns:netconf:base:1.0"
targetNamespace="urn:ietf:params:xml:ns:netconf:partial-lock:1.0"
elementFormDefault="qualified" attributeFormDefault="unqualified">
<xs:annotation>
<xs:documentation>
Schema defining the partial-lock and unlock operations.
organization "IETF NETCONF Working Group"
contact
"Balazs Lengyel
Ericsson Hungary, Inc.
balazs.lengyel@ericsson.com"
</xs:documentation>
</xs:annotation>
<xs:import namespace="urn:ietf:params:xml:ns:netconf:base:1.0"
schemaLocation="urn:ietf:params:xml:ns:netconf:base:1.0"/>
<xs:simpleType name="lock-id-type">
<xs:annotation>
<xs:documentation>
A number identifying a specific
partial-lock granted to a session.
It is allocated by the system, and SHOULD
be used in the unlock operation.
</xs:documentation>
</xs:annotation>
<xs:restriction base="xs:unsignedInt"/>
</xs:simpleType>
<xs:complexType name="partialLockType">
<xs:annotation>
<xs:documentation>
A NETCONF operation that locks part of one or more datastores.
</xs:documentation>
</xs:annotation>
<xs:complexContent>
<xs:extension base="nc:rpcOperationType">
<xs:sequence>
<xs:element name="target" maxOccurs="3">
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<xs:annotation>
<xs:documentation>
A list of one or more datastore names for NETCONF.
Each target element MUST contain a different
datastore name.
</xs:documentation>
</xs:annotation>
<xs:complexType>
<xs:choice>
<xs:element name="startup" minOccurs="0">
<xs:complexType/>
</xs:element>
<xs:element name="candidate" minOccurs="0">
<xs:complexType/>
</xs:element>
<xs:element name="running" minOccurs="0">
<xs:complexType/>
</xs:element>
</xs:choice>
</xs:complexType>
</xs:element>
<xs:element name="select" type="xs:string"
maxOccurs="unbounded">
<xs:annotation>
<xs:documentation>
XPath expression that specifies the scope of the lock.
An Instance Identifier expression must be used unless
the :xpath capability is supported in which case any
XPath 1.0 expression is allowed.
</xs:documentation>
</xs:annotation>
</xs:element>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<xs:complexType name="partialUnLockType">
<xs:annotation>
<xs:documentation>
A NETCONF operation that releases a previously acquired
partial-lock.
</xs:documentation>
</xs:annotation>
<xs:complexContent>
<xs:extension base="nc:rpcOperationType">
<xs:sequence>
<xs:element name="lock-id" type="lock-id-type">
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<xs:annotation>
<xs:documentation>
Identifies the lock to be released. MUST be the value
received in the response to the partial-lock operation.
</xs:documentation>
</xs:annotation>
</xs:element>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<!-- <partial-lock> operation -->
<xs:element name="partial-lock" type="partialLockType"
substitutionGroup="nc:rpcOperation"/>
<!-- <partial-unlock> operation -->
<xs:element name="partial-unlock" type="partialUnLockType"
substitutionGroup="nc:rpcOperation"/>
<!-- reply to <partial-lock> -->
<xs:complexType name="contentPartInPartialLockReplyType">
<xs:annotation>
<xs:documentation>
The content of the reply to a successful
partial-lock request MUST conform to this complex type.
</xs:documentation>
</xs:annotation>
<xs:sequence>
<xs:element name="lock-id" type="lock-id-type">
<xs:annotation>
<xs:documentation>
Identifies the lock to be released. Must be the value
received in the response to the partial-lock operation.
</xs:documentation>
</xs:annotation>
</xs:element>
<xs:element name="running" minOccurs="0">
<xs:annotation>
<xs:documentation>
List of locked nodes in the running datastore.
</xs:documentation>
</xs:annotation>
<xs:complexType>
<xs:sequence>
<xs:element name="locked-node" type="xs:string"
maxOccurs="unbounded">
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</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="candidate" minOccurs="0">
<xs:annotation>
<xs:documentation>
List of locked nodes in the candidate datastore.
</xs:documentation>
</xs:annotation>
<xs:complexType>
<xs:sequence>
<xs:element name="locked-node" type="xs:string"
maxOccurs="unbounded">
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="startup" minOccurs="0">
<xs:annotation>
<xs:documentation>
List of locked nodes in the startup datastore.
</xs:documentation>
</xs:annotation>
<xs:complexType>
<xs:sequence>
<xs:element name="locked-node" type="xs:string"
maxOccurs="unbounded">
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:schema>
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6. Appendix B - YANG Module for Partial Locking (non-normative)
The following YANG module defines the <partial-lock> and <partial-
unlock> operations. The YANG language is defined in
[I-D.ietf-netmod-yang].
module ietf-netconf-partial-lock {
namespace urn:ietf:params:xml:ns:netconf:partial-lock:1.0;
prefix pl;
organization "IETF NETCONF Working Group";
contact
"Balazs Lengyel
Ericsson
balazs.lengyel@ericsson.com";
description
"This YANG module defines the <partial-lock> and
<partial-unlock> operations.";
revision 2008-12-08 {
description "Initial version.";
}
typedef lock-id-type {
description "A number identifying a specific
partial-lock granted to a session.
It is allocated by the system, and SHOULD
be used in the partial-unlock operation.";
type uint32;
}
rpc partial-lock {
description
"A NETCONF operation that locks part of one or more datastores.";
input {
list target {
description "A list of one or more datastore names.
Each list entry must contain a different datastore name.";
min-elements 1;
max-elements 3;
choice datastore {
leaf running { type empty; }
leaf candidate { type empty; }
leaf startup { type empty; }
}
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}
leaf-list select {
description
"XPath expression that specifies the scope of the lock.
An Instance Identifier expression MUST be used unless the
:xpath capability is supported, in which case any XPath 1.0
expression is allowed.";
type string;
min-elements 1;
}
}
output {
leaf lock-id {
description
"Identifies the lock, if granted. The lock-id SHOULD be
used in the partial-unlock rpc.";
type lock-id-type;
}
container running {
leaf-list locked-node {
description "List of locked nodes
in the running datastore";
type instance-identifier;
}
}
container candidate {
leaf-list locked-node {
description "List of locked nodes
in the candidate datastore";
type instance-identifier;
}
}
container startup {
leaf-list locked-node {
description "List of locked nodes
in the startup datastore";
type instance-identifier;
}
}
}
}
rpc partial-unlock {
description
"A NETCONF operation that releases a previously acquired
partial-lock.";
input {
leaf lock-id {
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description
"Identifies the lock to be released. MUST be the value
received in the response to the partial-lock operation.";
type lock-id-type;
}
}
}
}
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7. Appendix C - Change Log
7.1. 04-05
Language and editorial updates
all app-tags are with dashes without spaces
Added usage scenarios
Changed encoding
Clarified definitions, separated scope of lock and protected area
7.2. 03-04
Minor clarifications
Added list of locked-nodes to the output of partial-lock.
Added <target> wrapper around datastore names.
Allowed atomic/one operation locking of datastore parts in multiple
datastores.
Improved English (hopefully)
Removed the <data> element from rpc-reply following the text of
rfc4741.
7.3. 02-03
Minor clarifications
Same descriptions in XSD and YANG.
7.4. 01-02
Made XSD normative
Clarified that no specific access control is assumed.
Clarified that non-existing nodes are NOT covered by the lock, even
if they where existing and covered by the lock when it was originally
granted.
Some rewording
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Added app-tags for two of the error cases.
Made YANG an informative reference
Enhanced security considerations.
7.5. 00-01
Added YANG module.
7.6. -00
Created from draft-lengyel-ngo-partial-lock-01.txt
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8. Acknowledgements
Thanks to Andy Bierman, Sharon Chisholm, Phil Shafer , David
Harrington, Mehmet Ersue, Wes Hardaker and many other members of the
NETCONF WG for providing important input to this document.
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9. References
9.1. Normative References
[NETCONF] Enns, R., "NETCONF Configuration Protocol", RFC 4741,
December 2006.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004.
9.2. Informative References
[I-D.ietf-netmod-yang]
Bjorklund, M., "YANG - A data modeling language for
NETCONF", draft-ietf-netmod-yang-02 (work in progress),
November 2008.
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Authors' Addresses
Balazs Lengyel
Ericsson
Email: balazs.lengyel@ericsson.com
Martin Bjorklund
Tail-f Systems
Email: mbj@tail-f.com
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Full Copyright Statement
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