This will allow Kubernetes resources that only pull images occasionally
(i.e., k8s jobs) to point to a static tag name, "latest", that is updated
regularly. It also means we can refer to that image in the k8s config
tracked in the repo, instead of out-of-date images.
Celery provides a more robust set of queueing options for both tasks and
worker processes. Updates include:
- infrastructure necessary to run Celery, including celery entrypoint
- backgrounded functions are now imported directly from atst.jobs
- update tests as-needed
- update kubernetes worker pod command
