fix(runners): temporarily reduce mac-finch-15-arm desired to 1 to unblock Prod wave - #1115
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…lock Prod wave mac2.metal ARM capacity in us-west-2 is exhausted: only 1 healthy instance exists and AWS cannot allocate a 2nd (all available mac2 hosts at 0 free capacity). The Production-ASG-mac-finch-15-armStack ASG wants DesiredCapacity=2, so CloudFormation cannot stabilize and the stack wedges (UPDATE_ROLLBACK_FAILED), blocking the Prod wave and the downstream Release wave (which carries the Windows update). Reduce runnerProd mac/15.7/arm/finch desiredInstances 2 -> 1 to match currently available capacity so the deploy stabilizes on the single existing instance. TEMPORARY: restore to 2 (and/or rely on the N+1 durability fix in #1113) once mac2.metal capacity is healthy. Complementary to #1113, which ADDS N+1 headroom (needs more capacity); this REDUCES demand to match current capacity. Signed-off-by: Arjun Yogidas <arjunry@amazon.com>
sondavidb
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Sep 4, 2026
sondavidb
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We should revert this once release is unblocked
shashank-boyapally
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Sep 4, 2026
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Problem
FinchPipeline wave.1 is blocked.
Production-ASG-mac-finch-15-armStackfails to deploy: its ASG wantsDesiredCapacity=2, but only 1mac2.metalARM instance is currently healthy and AWS has Insufficientmac2.metalcapacity inus-west-2to launch the 2nd (all 5 available mac2 hosts are at 0 free capacity; new-host allocation fails).CloudFormation cannot stabilize, so the stack wedges in
UPDATE_ROLLBACK_FAILED, blocking Prod and the downstream Release wave (which carries the Windows update).Change
This reduces demand to match currently available capacity so the deploy stabilizes on the single instance that already exists, unblocking the wave. No other runner entry is touched (mac 26.3 arm, mac 15.7 x86, windows 2022 x86, and all
finch-coreentries stay as-is).Temporary — revert plan
This is temporary. Once
mac2.metalcapacity is healthy, restoredesiredInstancesto2Note
The already-wedged
Production-ASG-mac-finch-15-armStack(UPDATE_ROLLBACK_FAILED) was recovered separately viacontinue-update-rollback; this PR prevents the ASG from re-wedging on the next deploy.Testing
npm ci— oknpm run build(tsc) — oknpm test(jest unit) — 12 suites / 15 tests passedNo unit test required updating.