On Mon, Feb 22, 2021 at 5:16 PM Corey Bryant <[email protected]> wrote:
> Hello SRU Team, > > I'm writing to discuss delivery of patches from extended maintenance > stable branches as snapshots. > > This would occur during the extended maintenance phase of an upstream > stable branch, which falls between the maintained phase and EOL phase. > I would see this process being similar to the current process that is used > to deliver stable point releases, described at: > https://wiki.ubuntu.com/OpenStack/StableReleaseUpdates. > > Snapshots refers to the process by which we currently deliver package > updates during a development release and prior to the final release. For > example, nova 3:22.0.1+git2021012713.d92c0740c6-0ubuntu1 in hirsute > contains everything in the upstream master git branch up to commit hash > d92c0740c6. > > == What is Extended Maintenance? == > First, it's worth understanding what the upstream "Maintained" phase is. > During this phase, upstream regularly releases stable point releases that > are based on a specific commit (e.g. the latest HEAD commit for the > stable/queens branch at a point in time), and we then package those point > releases up in distro. > > Following the "Maintained" phases is the "Extended Maintenance" phase. > During this phase, upstream no longer cuts any stable point releases for > that stable branch, however patches continue to be backported to the > branch. This is the phase where we would like to have the ability to > deliver snapshots of stable branches. This would allow us to pick up all > stable branch patches since, say, the final point release for stable/queens > (bionic). For example, the current version of nova in bionic is > 2:17.0.13-0ubuntu1, and that is based on the final point release for > upstream stable/queens. If we were to do a snapshot today for nova in > bionic, it would be versioned along the lines of > 2:17.0.13+git2021022200.944443a7b0-0ubuntu1. > > More details on upstream maintenance phases can be reviewed at: > https://docs.openstack.org/project-team-guide/stable-branches.html#maintenance-phases > > == Advantages of Stable Snapshots == > * Less overhead for the OpenStack engineering and SRU teams. Currently we > have various cherry-picked patches that are dealt with via separate SRU > bugs requiring individual testing. > * As the cherry-pick process is reactive, many of these SRUs tend to be > high impact or critical for users, requiring immediate action from these > teams. > * We have a lot of users that are now on, and moving to, bionic (queens) > and we would like to be more proactive in fixing bugs for them. > * This would naturally result in a regular cadence along the lines of the > monthly stable point release cadence that we currently follow. > * Cherry-picking individual patches can increase regression potential for > frequently modified code when they don't apply cleanly. > * All patches that have landed in an extended maintenance branch have > already landed in all ensuing stable branches and master, therefore > negating much of the regression potential mentioned in "Disadvantages" > below. > > == Disadvantages == > * Upstream stable branches that are in extended maintenance do not > guarantee the same upstream test coverage that supported branches do. The > maintenance-phases documentation states "There is no statement about the > level of testing and upgrades from Extended Maintenance are not supported > within the Community." > > == What Ubuntu Releases would this affect? == > Stable snapshots would only be needed for Ubuntu LTS releases (Upstream > "Maintained" period is 18 months for stable branches). Currently this would > only be applicable to Ubuntu 18.04 as bionic is the only LTS with a > corresponding upstream stable branch that's in extended maintenance. > > == How many patches are we talking about? == > For a sampling of stable/queens, new snapshots would pick up this many > patches: > > nova: 337 > neutron: 106 > heat: 47 > cinder: 21 > glance: 11 > designate: 11 > swift: 10 > horizon: 8 > keystone: 7 > > A few of those look daunting, yes, but perhaps that depends on how you > look at it. Also please keep in mind, queens has been in extended > maintenance since October of 2019 so this would be quite the one-time > waterfall for bionic. In the future we'd pick up fewer patches at a time at > a regular cadence. > > Thanks for taking the time to read this. Please let me know if you have > any opinions or questions about this approach. > > Corey > Hello SRU Team, I wanted to see if I could revive this topic and discuss the possibility of moving forward with stable snapshots as described in this thread. Would it make sense to add this to a meeting agenda or is the mailing list a good place to discuss? Thank you, Corey
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