Branch Model
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OpenStack branch model
Starting with the Diablo cycle, OpenStack core projects use a branching model close to the NVIE model that ensures a continuously-open trunk while still allowing to freeze features and select bugfixes in a release branch (milestone-proposed):
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At some point before the release of a milestone (called the "branch point"), the current state of trunk is merged into milestone-proposed, and trunk continues towards the development of the next milestone. The milestone-proposed branches gets testing and bugfixes (that are also backported to trunk), until the release is tagged.
Here are pointers to the branches:
Project | trunk |
Nova | lp:nova |
Glance | lp:glance |
Swift | lp:swift |
Version numbers
Since we have two branches in parallel, we use version numbers that allow to upgrade from one to the other.
For projects with milestones and releases (Nova, Glance):
- The trunk generates VERSION~DEVMILESTONE~DATE.TRUNKREV (nova-2011.3~d2~20110531.302)
- The milestone-proposed branch generates VERSION~MILESTONE~DATE.rMPREV (nova-2011.3~d1~20110531.r301)
- This gets copied to the milestone PPA at milestone delivery time as VERSION~MILESTONE (nova-2011.3~d1)
- This gets copied to the release PPA at coordinated release time as VERSION (nova-2011.3)
For projects where milestones == releases (Swift):
- The trunk generates DEVMILESTONE~DATE.TRUNKREV (swift-1.4.1~20110531.302)
- The milestone-proposed branch generates MILESTONE~DATE.rMPREV (swift-1.4.0~20110531.r301)
- This gets copied to the milestone PPA at milestone delivery time as MILESTONE (swift-1.4.0)
- The most recent milestone gets copied to the release PPA at coordinated release time
With:
- VERSION being the version of the project under development (2011.3)
- DEVMILESTONE being the short name of milestone under development (d2, 1.4.1...) and MILESTONE being the milestone to release (d1, 1.4.0...)
- DATE being under YYYYMMDD form
- TRUNKREV is the revision on trunk
- MPREV is the revision on milestone-proposed
Those (seemingly complex) version numbers actually ensure that you can smoothly upgrade in all scenarios (from trunk to milestone-proposed and back to trunk and to the final version...)