Distribution Version reporting¶
Overview¶
This section provides an overview of odl-distribution-version feature.
A remote user of OpenDaylight usually has access to RESTCONF and NETCONF northbound interfaces, but does not have access to the system OpenDaylight is running on. OpenDaylight has released multiple versions including Service Releases, and there are incompatible changes between them. In order to know which YANG modules to use, which bugs to expect and which workarounds to apply, such user would need to know the exact version of at least one OpenDaylight component.
There are indirect ways to deduce such version, but the direct way is enabled
by odl-distribution-version feature. Administrator can specify version strings,
which would be available to users via NETCONF, or via RESTCONF
if OpenDaylight is configured to initiate NETCONF connection
to its config subsystem northbound interface.
By default, users have write access to config subsystem, so they can add, modify or delete any version strings present there. Admins can only influence whether the feature is installed, and initial values.
Config subsystem is local only, not cluster aware, so each member reports versions independently. This is suitable for heterogeneous clusters. On homogeneous clusters, make sure you set and check every member.
Key APIs and Interfaces¶
Current implementation relies heavily on config-parent parent POM file from Controller project.
YANG model for config subsystem¶
Throughout this chapter, model denotes YANG module, and module denotes item in config subsystem module list.
Version functionality relies on config subsystem and its config YANG model.
The YANG model odl-distribution-version adds an identity odl-version
and augments /config:modules/module/configuration adding new case for odl-version type.
This case contains single leaf version, which would hold the version string.
Config subsystem can hold multiple modules, the version string should contain version of OpenDaylight component corresponding to the module name. As this is pure metadata with no consequence on OpenDaylight behavior, there is no prescribed scheme for choosing config module names. But see the default configuration file for examples.
Java API¶
Each config module needs to come with java classes which override customValidation()
and createInstance(). Version related modules have no impact on OpenDaylight internal behavior,
so the methods return void and dummy closeable respectively, without any side effect.
Default config file¶
Initial version values are set via config file odl-version.xml which is created in
$KARAF_HOME/etc/opendaylight/karaf/ upon installation of odl-distribution-version feature.
If admin wants to use different content, the file with desired content has to be created
there before feature installation happens.
By default, the config file defines two config modules, named odl-distribution-version
and odl-odlparent-version.
Currently the default version values are set to Maven property strings (as opposed to valid values), as the needed new functionality did not make it into Controller project in Boron. See Bug number 6003.
Karaf Feature¶
The odl-distribution-version feature is currently the only feature defined
in feature repository of artifactId features-distribution,
which is available (transitively) in OpenDaylight Karaf distribution.
RESTCONF usage¶
OpenDaylight config subsystem NETCONF northbound is not made available just by installing
odl-distribution-version, but most other feature installations would enable it.
RESTCONF interfaces are enabled by installing odl-restconf feature,
but that do not allow access to config subsystem by itself.
On single node deployments, installation of odl-netconf-connector-ssh is recommended,
which would configure controller-config device and its MD-SAL mount point.
See documentation for clustering on how to create similar devices for member modes,
as controller-config name is not unique in that context.
Assuming single node deployment and user located on the same system,
here is an example curl command accessing odl-odlparent-version config module:
curl 127.0.0.1:8181/restconf/config/network-topology:network-topology/topology/topology-netconf/node/controller-config/yang-ext:mount/config:modules/module/odl-distribution-version:odl-version/odl-odlparent-version