docs: warn that worker node pools must not auto-upgrade or use spot nodes - #1528
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Maya Wang (mayawang) wants to merge 1 commit into
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docs: warn that worker node pools must not auto-upgrade or use spot nodes#1528Maya Wang (mayawang) wants to merge 1 commit into
Maya Wang (mayawang) wants to merge 1 commit into
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An actor that is awake when its worker pod goes away moves to ACTOR_STATE_CRASHED, which is terminal: resume and suspend are both refused, there is no recover verb, and the snapshot the actor still holds cannot be used to start it. GKE enables node auto-upgrade by default and create cluster does not turn it off, so a cluster built from the documented path can lose actors on the provider's maintenance schedule with nothing in the install docs to warn about it. Add the prerequisite to the Create Cluster section, and state in the upgrade runbook what actually happens to an actor when a serving worker pool is edited or scaled down, rather than only that it should not be.
2 tasks
Maya Wang (mayawang)
requested review from
Haven Xia (HavenXia) and
Aditya Shantanu (aditya-shantanu)
September 7, 2026 22:03
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Documentation half of #1526.
What
Two additions, no code:
tools/setup-gcp/README.md, Create Cluster: a prerequisite saying node auto-upgrade must be off on any pool that runs workers, and that those nodes must not be spot or preemptible. It sits next to the beta-API warning, which is the block the quickstart already points bring-your-own-cluster users at.docs/upgrade.md: the runbook assumptions now state the same thing, and ground rule 2 says what actually happens to an actor when a serving worker pool is edited, rather than only that you should not edit one. Scaling a serving pool down is called out explicitly, since that is not obviously "editing" it.Why
An actor that is awake when its worker pod goes away moves to
ACTOR_STATE_CRASHED. That state is terminal:resumeandsuspendare both refused, there is no recover verb, and thelatestSnapshotthe actor still holds cannot be used to start it. The actor has to be deleted and recreated.buildCreateClusterRequestsets noManagementon the node pool, so GKE's default applies and auto-upgrade is on. Nothing in the install documentation mentions it. A cluster built exactly as documented can therefore lose actors on Google's maintenance schedule, and the operator has no way to know that in advance.Found during acceptance testing on
release-0.1atc48b3a3c, where aWorkerPoolscaled from 12 replicas to 9 destroyed two of ten actors permanently. That scale-down was our mistake and ground rule 2 already covered it, which is why this PR is scoped to documentation. What the docs did not cover is that the consequence is permanent, or that a trigger exists which fires without an operator doing anything.Scope
This does not fix the underlying behaviour and is not a substitute for #1526. Auto-repair, preemption and OOM kills reach the same path and no prerequisite can close them. Telling operators to disable a standard Kubernetes safety feature is a reasonable answer for this release and not a reasonable one for 1.0, so the precondition relaxation in #1526 is still owed.
Testing
Docs only.
make testpasses.make verifydoes not complete in my environment:hack/verify/codegen.shfails creating the Locust codegen virtualenv becausepython3-venvis not installed locally, which is unrelated to this change.