docs(rfc): Independent compute release flow

[ololobus]

Related to https://github.com/neondatabase/cloud/issues/11698

[github-actions]

4986 tests run: 4822 passed, 0 failed, 164 skipped (full report)

---

Flaky tests (9)

Postgres 17

• test_pageserver_compaction_smoke: release-x86-64
• test_pg_regress[4]: debug-x86-64
• test_timeline_archive[4]: debug-x86-64
• test_restart_endpoint_after_switch_wal: release-x86-64

Postgres 16

• test_slots_and_branching: release-arm64

Postgres 15

• test_neon_cli_basics: release-arm64

Postgres 14

• test_lfc_resize: release-arm64
• test_neon_cli_basics: release-arm64
• test_subscriber_restart: release-x86-64

Code coverage* (full report)

• functions: 32.1% (7455 of 23225 functions)
• lines: 49.9% (60101 of 120333 lines)

* collected from Rust tests only

---

_{The comment gets automatically updated with the latest test results
1939b99 at 2024-09-24T00:02:32.818Z :recycle:}

[hlinnaka]

Overall, I like it

[bayandin]

Should we adjust the compute pool logic for the proposed release changes? Probably not, but asking just in case

[mtyazici]

LGTM as well, I am a bit hesitant to the alternative Helm approach though.

[ololobus]

Should we adjust the compute pool logic for the proposed release changes? Probably not, but asking just in case

For now, we shouldn't. With this v1 release flow it's expected that we will start all new computes in the pool with a new version, while we still re-utilize old pre-created ones, if there is a shortage of new computes. Later, yes, we would need to teach pools to maintain pools with both versions if we want kinda canary deployments within the same region / control plane

[problame]

Overall plus one, especially the compute_releases table will be a huge step forward.

I'm concerned about the ignorance in this PR about merge strategies, see my comments on that. I think it needs a bit more forethought.

Maybe I missed it, but, I think there should be a "Unique Selling Point" section outlining why we want the compute_releases table. I know from our 1:1 discussions, but, it's not written down here. IIRC that was

• ability to prewarm pools with new image to avoid misses
  • especially important once we do slow rollout strategies where pools will need to maintain pre-warmed computes for both old and new image for the duration of the rollout
• extension stuff (I forgot the details, we talked about it 1:1 like 3-4 months ago)

[ololobus]

especially important once we do slow rollout strategies where pools will need to maintain pre-warmed computes for both old and new image for the duration of the rollout

I didn't want this to be part of v1 because it requires a lot of changes on the control plane side, but I briefly mentioned that in the Further work section https://github.com/neondatabase/neon/pull/8881/files#diff-39df61b534dc5f736661bd5f139140b573a0f35c32524866e0339e425b9f22e4R299

extension stuff

Yeah, I mentioned that too, but waiting for the Anastasia's input here, as I don't know this part well enough yet #8881 (comment). I only know that we need some metadata in cplane and compute to make remote extensions working, but don't know how exactly it's produced