[openstack-dev] [TripleO] tripleoclient/tripleo-common backwards compatibility
shardy at redhat.com
Mon Dec 21 13:35:54 UTC 2015
So I've recently had several discussions related to $subject.
In summary - there's a requirement to enable underclouds to support
deploying/updating previous versions of OpenStack overclouds.
So, say I upgrade my liberty undercloud to master/mitaka, I'd like to
ensure the following is possible:
1. Maintain any existing (liberty) overcloud without being forced to
immediately upgrade to Mitaka (updating the undercloud can pull in features
required to enable this upgrade however).
2. Deploy a new overcloud, with the choice between either liberty or mitaka
This has some implications related to distributing tripleo-heat-templates
(need to allow for packaging to either install both versions of t-h-t, or
always install all versions via one package), and then there are related
requirements related to tripleoclient (and potentially tripleo-common), so
we maintain backwards compatiblity wrt overcloud deployment/update.
So, some questions:
- Do we actually want stable branches for tripleoclient (or even
tripleo-common?) if we have to maintain backwards compatibility?
- Can we add features to tripleoclient now, to make it easier to
pre-configure known locations for specific releases (this should be
configurable via a config file IMO, not hard-coded)?
- How might we effectively test this in CI? Have a job which deploys e.g
a stable/liberty overcloud with a master undercloud?
- How hard would it be to wire in image-building for a previous release
(Mitaka/master undercloud building liberty overcloud-full) - would it be
reasonable to assume existing images and say the undercloud only supports
building images for one release version?
Thoughts and feedback and volunteers appreciated, thanks!
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