for a large data processing pipeline I have, I built a bunch of docker containers grouped into a swarm with docker-compose.yaml file. they're not http servers or this kind of micro-services, just plain (sometimes replicated) executables and clients performing batch workloads.
as it's a pipeline - I sometime need one workload to terminate before other ones starts. the docker documentation advocates for tools like wait-for-it.sh and dockerize which I find are aimed towards servers and services and not towards clients (they don't expose a port or anything I can listen to).
my question is what's the best way to signal another fleet of services their start-condition was met, there must be some way to bind on termination of another service. I don't want to use more complex tools like rabbitmq when all I need is to know what service stopped
so eventually I didn't exactly control the startup order (although dockerize definitively can do that) because I understood that in such a distributed setup I need something more structured to schedule tasks. I ended up using rabbitmq but I guess airflow etc. could also do the trick