It's a bit about features - but it's more an attempt to achieve the goals of what might happen with a 4 week release cycle (but that itself -- in practice didn't prove to be valid/reasonable).
If something like an executor service for performance is changed (for example) it is definitely a more risky change than what would currently go into 1.2 -- but most likely we would want to get patches like that into a usable build. So I guess: a) reduce code drift between branches we run in production b) get newer "features" into production faster where breaking changes aren't required for the scope of the patch. Additionally - it's also a question of what release we use when we identify an issue we want to work on internally. If we are on 1.2 because we can't yet take ALL of 2.0 - do we now need to target our work against 1.2? I would rather write it against the months worth of changes that have happened since. Finally, it's an attempt to make the internal forking not as common as it might be today. As you said - this is somewhat of a common process. > On Jun 17, 2014, at 8:52 AM, "Jake Luciani" <jak...@gmail.com> wrote > > Hi Michael, > > I didn't get to hear the in person conversation so taking a step back. > The proposal seems to be in response to a common problem. i.e. I'm on C* > version X and I need feature Y which is only available on version Z. Is > this correct? > > The options have been: a) upgrade to version Z or b) fork C* and backport. > Coming my my previous job where I ran a prod C* cluster I felt this and I > expect many others do too. We did have to fork and backport patches we > needed and it was hard. > > This is specific to features and not bugs, since bugs are fixed in all > versions affected. > > -Jake > > > > > > > On Tue, Jun 17, 2014 at 3:16 AM, Michael Kjellman < > mkjell...@internalcircle.com> wrote: > >> Hi Dev@ List— >> >> TL;DR: >> I’d love it if we could modify the C* release cycle to include an >> additional “experimental” release branch that straddles the current major >> releases that includes somewhat “untested” or “risky” commits that normally >> would only go into the next major release. Releases based from this branch >> wouldn’t contain any features that require breaking changes or are >> considered highly “untested” or “risky” but would include the many other >> commits that today are considered too unsafe to put into the previous >> stable branch. This will allow us to run code closer to the current stable >> release branch when we are unable to move fully to the new major release >> branch. Also, during the release cycle of the next major release branch the >> project can get feedback from a subset of the total changes that will >> ultimately make it into that final new major release. Also — i’m aware that >> any additional branches/releases will add additional work for any developer >> that works on C*. It would be great if we could strike a balance that >> hopefully doesn’t add significant additional merging/rebasing/work for the >> team... >> >> The Longer Story: >> Last week I had a conversation with a few people regarding a proposed >> change to the current C* release schedule. >> >> Other than an attempt to make Jonathan and Sylvian’s lives more difficult, >> it would be ideal if we could better sync our internal release schedule >> with more recent Cassandra releases. The current cycle has resulted in >> currently “active” branches for 1.2, 2.0, 2.1, and +3.0. Official stable >> releases are from 2.0, beta’s/RC’s from 2.1, and there is the potential for >> another out-of-band 1.2/previous stable release build. We would love to >> always run the current “stable” release in production but >> generally/historically it takes time and a few minor releases to the >> current “major” branch stable to get to a state where we can accept for use >> in production. Additionally, as major releases are currently used to make >> “breaking” changes that require a more involved and risky upgrade process, >> it’s a much bigger deal to deploy a new major into production than a >> release without breaking changes. (upgrade-sstables for example is required >> when upgrading to a new major release branch. this unavoidable step adds >> lots of temporary load to the cluster and means deploying/upgrading to >> major releases tends to be a bit more risky than between minor releases and >> a more involved/long running process). This means even though there are >> months worth of stable hard work/awesome improvements in the current >> “stable” major release branch (today this is 2.0), we end up with an >> unavoidable and undesired lag in getting more recent C* changes pushed into >> production. This means we are unable to provide feedback on newer changes >> sooner to the community, stuck and unable to get even a subset of the >> awesome changes as we can’t yet take ALL the changes from the new major >> release branch, and finally if we find an issue in production or want to >> work on new functionality it would be ideal if we can write it against a >> release that is closer to the next major release while also providing us a >> reasonable way to get the feature deployed internally on a branch we are >> running. >> >> Currently, the project generally tends to include all risky/breaking/more >> “feature” oriented tickets only into the next major release + trunk. >> However, there is a subset of these changes that are “somewhat” more risky >> changes but pose little/less/no risk the commit with introduce a regression >> outside of the scope of the patch/component. Additionally, any changes that >> depend on other higher risk/breaking commits/changes wouldn’t be >> candidates for this proposed release branch. In a perfect world we would >> love to target a new “interim” or “experimental” train of releases which is >> loosely the most stable current release train but also includes a subset of >> changes from the next major train. (While we were discussing we thought >> about possible parallels to the concept of a LTS (Long Term Support) >> release cycle and what some people have dubbed the “tick-tock” release >> cycle.) This might look something like 1.2 branch + all >> moderately-to-“less”-risky/non-breaking commits which currently would only >> end up in a 2.0 or 2.1 release. (Off the top of my head, immediately bad >> candidates for this build would be for changes to components such as >> gossip, streaming, or any patch that changes the storage format etc). This >> would enable the project to provide builds for more active/risk-adverse >> users looking for a reasonable way to get more features and changes into >> production than with today’s release cycle. Additionally, this would >> hopefully facilitate/increase quicker feedback to the project on a subset >> of the new major release branch and any bugs found could be reported >> against an actual reproducible release instead of some custom build with a >> given number of patches from Jira or git SHAs applied/backported. >> >> As it will always take both time and n releases to reach a stable minor >> release for a new major train; users could deploy this new release to get a >> subset of new features and changes with higher risk than would otherwise go >> into a minor release of the previous stable release train. If internally we >> wanted to add a new feature we could target this release while testing >> internally, and hopefully given the smaller delta between this >> “interim/experimental” to make it easier to re-base patches into the next >> major release train. This would help us avoid what today has unfortunately >> become a unavoidable large lag in getting new C* builds into production as >> while we attempt to sync our internal releases with a internally/or >> community QA’ed/accepted build/release of the current “stable” build/branch >> (currently this is 2.0). >> >> To accomplish this, the commit workflow would unfortunately need change >> where an additional process is added to determine “eligibility” or >> “appropriateness” of a given commit to additionally also be committed to >> the “experimental” build branch (maybe it’s as simple as leaving it up to >> the reviewer + author to determine the risk factor and difficulty in >> merging the change back into the “experimental” build?). If it is agreed >> the commit/change/patch is a good candidate for the “experimental” branch, >> in addition to committing the patch to the current major release branch, >> the commit would also be merged into the new “experimental” release. If >> commits make it into the “experimental” branch frequently, I would >> expect/hope merging patches into the “experimental” build would be >> relatively easy as the “experimental” branch should also have most of the >> changes from the major release branch sans those considered highly risky or >> breaking. Additionally, if internally we want to work on a new feature and >> test internally before submitting a patch, we could target our code against >> the “experimental” branch, allowing us to test our changes in production >> without forking C* internally, writing our code against more recent >> “modern” changes, and then hopefully getting that work back to the >> community. >> >> >> Hope this was clear enough and accurately summarizes the conversation a >> few of us had! Looking forward to everyone’s feedback and comments. >> >> best, >> kjellman > > > > > -- > http://twitter.com/tjake
