how to do one by one roll out?

[DeoLeung]

thanks for the great tool

we are facing a problem on a limiting resource machine, start all the new containers first would cause resource problem.

can it do one by one roll out? like starts 1 new container, stop 1, then repeats?

[wowu]

Interesting idea, with current script it is not possible, and would require changes.

Maybe we can add a --parallelism argument to work similarly to docker swarm with the deploy configuration block https://docs.docker.com/reference/compose-file/deploy/#update_config. So adding --parallelism 1 would run only 1 extra container at the time.

What is your use case for running multiple copies of the same container on a single host? How many containers do you have? Would adding a --parallelism option solve your case?

[DeoLeung]

there was long debate about running multiple fastapi process in one container or one process per container :)
we just pick running two in one container, no specific reason :) , but i think either way in current rollout method the extra memory/cpu consumption would be the same.
we are on a 16c32g machine, and just two containers with each two fastapi processes. as time passes we added more extra services on it so it's memory goes to near alarm threshold, then each time we deploy, the memory peaks a bit and there would be a false alarm, so we wonder whether we could have a more resource friendly way to do graceful rollout.