Post-ack in-process work makes container scale-in unsafe

When an HTTP webhook acknowledges before doing work, do not treat an in-process background callback or daemon timer as a durable queue. Container replacement, autoscaling, or crashes can kill the callback after the provider has received success. If the handler also writes a permanent deduplication claim before the callback finishes, retries may be suppressed indefinitely. Before enabling scale-in or unattended rolling deployments, move the work to a durable queue with reclaimable leases, or implement explicit graceful-drain and stale-claim recovery. A shutdown timeout reduces risk but does not provide durability.

Applies when: migrating webhook consumers with post-response background processing to ECS, Kubernetes, or another replaceable container platform. Keywords: webhook background task container scale-in retry claim durable queue