[DOCS-110] Add docs about ODL upgrade strategies

Wed, 3 Oct 2018 15:45:21 +0000

ODL has a somewhat complex upgrades story. We should create some specific docs dedicated to known/recommended upgrade strategies and their limitations. trade-offs and mitigations.

For example, topics to cover:

Data store upgrades being difficult at the moment, how to do yang schema migrations
Possible to work-around in some deployments by doing replay of events (say from OpenStack Neutron) to ODL. Can do OVS table updates in atomic batch, no dataplane downtime.
Additional suggestion is to deploy ODL in a container so can do update by swapping for newer-version container.
Configuration management tooling like ansible-opendaylight and puppet-opendaylight handle upgrades because they assume no yang model schema upgrades. This is normally okay, and almost certainly okay between SR releases.
RPM upgrade tests are WIP, link to patch.

OpenDaylight JIRA

[DOCS-110] Add docs about ODL upgrade strategies