framework
Celery is a distributed task queue framework for Python, used to run asynchronous and scheduled jobs outside the main request path.
A rule can evaluate cleanly, appear in the rule list, report healthy, and still be incapable of going red. One team found four of those in its own stack, and the PromQL one turned on a missing keyword.
Reality
RabbitMQ 4.2.2 drops global QoS and classic queue mirroring, so a Celery task with an ETA parks its worker until the ETA arrives. Because a queue's type is fixed at declaration, the fix has to land in the application first.
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A developer told Claude Code not to ship until billing worked against real infrastructure, so the agent stood up Postgres, Redis and both tiers on Render, bought a sandbox subscription, and hit a race the tests never posed.
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The Jetson holds one model at a time, so every job has to pass a single admission gateway. That gateway had to run on a box already carrying DNS and 9.4 GiB of committed memory. Footprint settled the build-versus-adopt question before features came up.
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A team's Debian 11-to-12 move across 28 hosts put the usual Ansible complaints under load. The failure that actually stopped the run sat in the SSH layer the tool does not own.
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DailyMeteo serves 11 TB of GeoTIFFs from a Django app reading files off a disk. The load-bearing choices are a dedicated production box and a pull-based rsync every 30 minutes.
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