+1 (binding) Nicolò Boschi
Il giorno gio 9 feb 2023 alle ore 11:17 Zike Yang <z...@apache.org> ha scritto: > +1 (non-binding) > > Thanks, > Zike Yang > > On Thu, Feb 9, 2023 at 5:28 PM PengHui Li <codelipeng...@gmail.com> wrote: > > > > +1 (binding) > > > > Penghui > > > > > On Feb 9, 2023, at 17:24, Nozomi Kurihara <nkuri...@apache.org> wrote: > > > > > > +1 > > > > > > The LTS plan seems clear and helpful for users. > > > > > > Thanks, > > > Nozomi > > > > > > 2023年2月9日(木) 5:44 Matteo Merli <matteo.me...@gmail.com>: > > > > > >> https://github.com/apache/pulsar/issues/15966 > > >> > > >> > > >> > ---------------------------------------------------------------------------------------- > > >> > > >> > > >> ## Motivation > > >> > > >> In PIP-47 ( > > >> https://github.com/apache/pulsar/wiki/PIP-47:-Time-Based-Release-Plan), > we > > >> have adopted a time-based release plan. This was the first attempt at > > >> establishing a new principle on how releases should b > > >> > > >> The main two benefits of this approach have been: > > >> > > >> 1. Clarity for users and developers on when to expect a release > > >> 2. Breaking a hard relationship between feature and release: a > particular > > >> feature will be included in the release if it is completed in time. > > >> Otherwise, it will be bubbled up to the next release. > > >> > > >> The motivation for the current proposal is to extend the existing > process > > >> to address the issues that we have seen and that were left out of the > scope > > >> of PIP-47. > > >> > > >> ## Summary of existing issues in the process > > >> > > >> ### Short maintenance cycles for releases > > >> > > >> Since we're doing a 3 months release cycle, we are ending with 4 > releases > > >> done per year, even though it's more close to 3 releases. > > >> > > >> There is a high cost to maintain a lot of old releases, backport bug > fixes, > > >> and security patches. In general, we actively support the last 3 minor > > >> releases while continuing to develop the next release. E.g., 2.8, > 2.9, and > > >> 2.10, while 2.11 is under development. > > >> > > >> The result is that a user adopting a particular release is forced to > > >> upgrade in a < 1-year timeframe to keep up to date and use a supported > > >> release. This timeframe is too short for many users as it imposes a > lot of > > >> forced upgrades, for which they are not prepared in terms of > available time > > >> and required effort. > > >> > > >> ### Live Upgrade/Downgrade compatibility path > > >> > > >> In Pulsar, we guarantee that users have a way to do live upgrades and > > >> downgrades with zero downtime. > > >> > > >> This is very powerful because it gives them the freedom to upgrade to > a new > > >> release with the assurance of being able to roll back to the previous > > >> release in case any functional or performance regressions are > encountered. > > >> > > >> Today, this compatibility is guaranteed across minor versions. Eg: I > can do > > >> `2.7 -> 2.8 -> 2.7` as a live upgrade. > > >> > > >> What is not guaranteed is to "skip" releases. E.g.: `2.7 -> 2.9` > might work > > >> or not, but it's not guaranteed. In that case an intermediated upgrade > > >> would be required: `2.7 -> 2.8 -> 2.9`. > > >> > > >> The reasons for which the "skip" upgrade might not work are multiple: > > >> 1. Incompatible upgrade of some dependency (e.g., ZooKeeper) that > might > > >> not be compatible with an older version. > > >> 2. Adoption of a new metadata format or data format on disk. > > >> Every time we introduce a new incompatible format change (outside > of a > > >> regular Protobuf field addition), we do it in a 2 steps way: > > >> - In a new release, we introduce the new feature/format, > disabled by > > >> default. The new release can read both old and new formats, though it > keeps > > >> writing the old format by default. > > >> - In a subsequent release, we change the default to the new > format > > >> > > >> Note that this consideration is separate from the compatibility > between > > >> clients and brokers, where we ***never*** break compatibility. The > oldest > > >> available Pulsar client can still talk with the newest Pulsar broker, > and > > >> vice versa, a new client, will be perfectly fine with an older broker > > >> (except the new features won't be working). > > >> > > >> ### Releases getting delayed > > >> > > >> Another problem we have been experiencing is that release cycles have > been > > >> stretching considerably. Part of this has been because we have been > > >> reaching the end of the release window, preparing a candidate, and > then > > >> taking a long time to flush out all issues found at the last minute > in the > > >> new release. > > >> > > >> We need to ensure that we have a date set in stone to deliver the > release > > >> to users. > > >> > > >> ## Proposal > > >> > > >> The proposal to address the above issues is composed of 2 parts. > > >> > > >> ### 1. Establish Long Term Support releases > > >> > > >> We need to provide a way for users to quickly understand the expected > > >> lifecycle timeline of a given release and for that timeline to be long > > >> enough not to be a constant update mandate. > > >> > > >> At the same time, we need to ensure that we maintainers are not > spending > > >> all the time just maintaining a huge list of old releases. > > >> > > >> For that, we can use the established concept of "Long Term Releases" > or > > >> LTS. > > >> > > >> We will perform LTS releases at a fixed cadence every 18 months, and > we > > >> will keep doing regular feature releases every 3 months as we're > currently > > >> doing. > > >> > > >> The LTS releases will be identified by being a `.0` version. For > example: > > >> * `3.0` -> LTS > > >> * `3.1` -> regular release > > >> * `3.2` -> regular release > > >> * `4.0` -> LTS > > >> > > >> The major version bump will not carry any special meaning in terms of > "big > > >> features" included in the release or breaking API changes. Instead, it > > >> would simply signal the type of the release. > > >> > > >> #### Compatibility between releases > > >> > > >> It will be guaranteed to be able to do a live upgrade/downgrade > between one > > >> LTS and the next one. > > >> > > >> For example: > > >> > > >> * `3.0 -> 4.0 -> 3.0` : OK > > >> * `3.2 -> 4.0 -> 3.2` : OK > > >> * `3.2 -> 4.4 -> 3.2` : OK > > >> * `3.2 -> 5.0` : Not OK > > >> > > >> #### Release support expectation > > >> > > >> We will publish clear guidelines on the Pulsar website regarding the > > >> expected timeline for which each release is supported and when the new > > >> feature and LTS releases will be available. > > >> > > >> The support model will be: > > >> > > >> * LTS > > >> * Released every 18 months > > >> * Support for 24 months > > >> * Security patches for 36 months > > >> * Feature releases > > >> * Released every 3 months > > >> * Support for 6 months > > >> * Security patches for 6 months > > >> > > >> This can be translated into: > > >> * We support the last 2 LTS releases and the last 2 feature releases > > >> * Security patches are provided for the past 3 LTS releases and 2 > > >> feature releases > > >> > > >> Users are therefore encouraged to stay in an LTS release until they > are > > >> ready to jump into the next LTS unless they want to have access to > some of > > >> the features included in the latest feature releases. > > >> > > >> ### 2. Introduce a code-freeze period in the release cycle > > >> > > >> To address the problem with delayed release cycles, we are > introducing a > > >> code freeze period that will give us time to stabilize the release > code > > >> while not blocking new changes from being merged into master for the > > >> subsequent version. > > >> > > >> This code-freeze will only be adopted for LTS/feature releases, not > for any > > >> patch release. > > >> > > >> In a 3 months release cycle, the last 3 weeks will be marked as a code > > >> freeze period. The release manager will branch off from master, and > he will > > >> be responsible for selecting the changes that will be cherry-picked > in the > > >> release branch. > > >> > > >> From the code-freeze point, to minimize the risk of delaying the > release, > > >> only bug fixes involving a regression of behavior compared to a > previous > > >> release should be allowed. Occasional exceptions will be possible > after > > >> higher scrutiny of the change. > > >> > > >> At the moment of the code freeze, the release manager will also > prepare a > > >> release candidate in the same way we are doing today. Committers, > > >> contributors, and users will test this RC to detect issues as early as > > >> possible. > > >> > > >> A formal vote by the PMC will not be required at this stage (though > any > > >> disagreement should be sent out ASAP). > > >> > > >> After 1 week, if there are any changes, the release manager will > provide a > > >> new RC release that the community will test again. > > >> > > >> After 1 more week, if there are any changes, a third RC will be > prepared, > > >> and this will be submitted to vote to the PMC. Otherwise, the vote > will be > > >> held on an earlier RC release if no issues are found. > > >> > > >> The last 1 week will be used for the voting process and for updating > Pulsar > > >> website and the blog post announcing the release, which should > (hopefully) > > >> happen on the scheduled day. > > >> > > >> > > >> -- > > >> Matteo Merli > > >> <matteo.me...@gmail.com> > > >> > > >
