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From Jason Brown <jasedbr...@gmail.com>
Subject Re: Proposed changes to C* Release Schedule
Date Tue, 17 Jun 2014 17:32:48 GMT
FWIW, here's the ubuntu wiki on their release model:
https://wiki.ubuntu.com/TimeBasedReleases

Short story: they have a feature set for each release, and it must be
tested thoroughly before going out the door. Granted, they are shipping an
entire OS with 1000s of components that all must work well *together*, but
there may be something we can learn from their process - I'm not
necessarily recommending we adopt it, but it seems to work for Ubuntu.

-Jason



On Tue, Jun 17, 2014 at 10:27 AM, Jake Luciani <jakers@gmail.com> wrote:

> So there are two issues this proposal is trying to address:
>
> 1. Shrink the release cycle.
>
> 2. Backport things to stable releases.
>
> We should discuss these separately since together it's hard to discuss.
> 1. is less controversial I would think :)
>
>
>
>
>
>
> On Tue, Jun 17, 2014 at 1:16 PM, Michael Kjellman <
> mkjellman@internalcircle.com> wrote:
>
> > Totally agree — "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…”
> >
> > That being said I don’t think i’m alone by identifying the problem. The
> > proposed solution was what we came up with in the hour or so we discussed
> > this in person. How else can you shrink the release schedule without
> > creating another branch? Also — the idea is to only have this branch
> > “active” during the overlap when major release branches need to
> stabilize.
> >
> > > On Jun 17, 2014, at 10:03 AM, Brandon Williams <driftx@gmail.com>
> wrote:
> > >
> > > If that's what we want, merging is going to be much more painful.
> > > Currently we merge:
> > >
> > > 1.2->2.0->2.1->3.0
> > >
> > > If we add an experimental branch for each, we still have to merge the
> > > stable branch into experiemental:
> > >
> > > 1-2->1.2ex, 2.0->2.0ex, 2.1->2.1ex, 3.0->3.0ex
> > >
> > > And then the experimentals into each other:
> > >
> > > 1.2ex->2.0ex, 2.0ex->2.1ex, 2.1ex->3.0ex
> > >
> > > That's quite a lot of merging in the end.
> > >
> > >
> > > On Tue, Jun 17, 2014 at 11:51 AM, Jake Luciani <jakers@gmail.com>
> wrote:
> > >
> > >> I'm not sure many people have the problem you are describing.  This is
> > more
> > >> of a C* developer issue than a C* user issue.
> > >>
> > >>
> > >> Is the below what you are describing we move to?:
> > >>
> > >> 1.2 -> 2.0 -> 2.1 -> 3.0 stable
> > >> 1.2 <- 2.0 <- 2.1 <- 3.0 experimental
> > >>
> > >> Specific changes would be backported based on the "less riskyness" of
> > the
> > >> change which you are assuming will be constant across versions?
> > >>
> > >> -Jake
> > >>
> > >>
> > >>
> > >>
> > >> On Tue, Jun 17, 2014 at 12:28 PM, Michael Kjellman <
> > >> mkjellman@internalcircle.com> wrote:
> > >>
> > >>> 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" <jakers@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 <
> > >>>> mkjellman@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
> > >>>
> > >>
> > >>
> > >>
> > >> --
> > >> http://twitter.com/tjake
> > >>
> >
> >
>
>
> --
> http://twitter.com/tjake
>

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