Docker Swarm - indicate a container is busy and shouldn't be terminated?

Question

This may be an odd question, and I suspect the answer is a resounding "no, this isn't possible", but I'd rather ask anyway.

I've got a Docker Swarm setup running some Windows containers with DevOps Agents for our CI/CD needs. This is all nice and well. The problem is if I want to update the images I'm using on these containers. At the moment I need to:

1. Disable all agents belonging to a particular Docker host in our DevOps Server (on-prem)
2. Wait for any queued jobs to finish (if there are any)
3. Restart the stack / service with a new image + enable all the agents in DevOps

Ideally I'd like to just queue up the image update for the Docker service and let that handle everything. Alas, if I did so now Docker would just kill the containers one by one with complete disregard for any running jobs. And the problem is point #2 can sometimes take a lot of time.

Is it possible to somehow have a container inform Docker that it is "busy" and shouldn't be terminated?

Answer 1

Docker service update has the following flag:
--stop-grace-period duration Time to wait before force killing a container (ns|us|ms|s|m|h) which is mirrored in compose/stack yaml: stop_grace_period

Whether or not this works (and how) on windows remains an open question.

tl;dr don't use windows containers.