Commit merging: scope and cadence

Commits are merged into branches according to criteria specific to each phase of the Ceph release lifecycle. This chapter codifies these criteria.

Development releases (i.e. x.0.z)

What ?

Features
Bug fixes

Where ?

Features are merged to the main branch. Bug fixes should be merged to the corresponding named branch (e.g. nautilus for 14.0.z, pacific for 16.0.z, etc.). However, this is not mandatory - bug fixes and documentation enhancements can be merged to the main branch as well, since the main branch is itself occasionally merged to the named branch during the development releases phase. In either case, if a bug fix is important it can also be flagged for backport to one or more previous stable releases.

When ?

After each stable release, candidate branches for previous releases enter phase 2 (see below). For example: the jewel named branch was created when the infernalis release candidates entered phase 2. From this point on, main was no longer associated with infernalis. After he named branch of the next stable release is created, main will be occasionally merged into it.

Branch merges

The latest stable release branch is merged periodically into main.
The main branch is merged periodically into the branch of the stable release.
The main is merged into the stable release branch immediately after each development (x.0.z) release.

Stable release candidates (i.e. x.1.z) phase 1

What ?

Bug fixes only

Where ?

The stable release branch (e.g. jewel for 10.0.z, luminous for 12.0.z, etc.) or main. Bug fixes should be merged to the named branch corresponding to the stable release candidate (e.g. jewel for 10.1.z) or to main. During this phase, all commits to main will be merged to the named branch, and vice versa. In other words, it makes no difference whether a commit is merged to the named branch or to main - it will make it into the next release candidate either way.

When ?

After the first stable release candidate is published, i.e. after the x.1.0 tag is set in the release branch.

Branch merges

The stable release branch is merged periodically into main.
The main branch is merged periodically into the stable release branch.
The main branch is merged into the stable release branch immediately after each x.1.z release candidate.

Stable release candidates (i.e. x.1.z) phase 2

What ?

Bug fixes only

Where ?

The stable release branch (e.g. mimic for 13.0.z, octopus for 15.0.z ,etc.). During this phase, all commits to the named branch will be merged into main. Cherry-picking to the named branch during release candidate phase 2 is performed manually since the official backporting process begins only when the release is pronounced “stable”.

When ?

After the CLT announces that it is time for phase 2 to happen.

Branch merges

The stable release branch is occasionally merged into main.

Stable releases (i.e. x.2.z)

What ?

Bug fixes
Features are sometime accepted
Commits should be cherry-picked from main when possible
Commits that are not cherry-picked from main must pertain to a bug unique to the stable release
See also the backport HOWTO document

Where ?

The stable release branch (hammer for 0.94.x, infernalis for 9.2.x, etc.)

When ?

After the stable release is published, i.e. after the “vx.2.0” tag is set in the release branch.

Branch merges

Never

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