Triggering one manual backup, starts all backups

[hendrikVandeput]

I have 3 docker-volume-backup containers running, each responsible for different volumes. When I try to run 1 manually to test, they all start.
I start the one container with:
docker exec container_id backup

I'm assuming it's the result of the shared docker.sock, why is this necessary?
Is this behaviour expected?

[m90]

This doesn't sound right somehow. Running docker exec like shown will not trigger processes in other containers, no matter the Docker socket. Are you sure this isn't an issue with your configuration and it does different things than you would expect it to?

[hendrikVandeput]

I've got multiple separate docker-compose.yml files, each in their own folder. To each I've added this container to manage the backups. When testing one, i see the logs of all of them.
I'm not sure how that can happen, I wouldn't expect it to.

[m90]

So If you're seeing the log output from 3 containers, you must somehow invoke the command in all 3 of them. It's not possible that one invocation spawns siblings in other containers.

How exactly this is happening in your case is hard to tell for me.

[hendrikVandeput]

yeah I don't understand either, now it does work so I think it will be fine.

[hendrikVandeput]

@m90 I've found out more information.
Not all backups are firing when executing on one container, but all docker-volume-backup trackers are firing. This means that if one backups is being generated, the mysql dump for all databases on the server are being generated and all wget's are being send as well.

I've removed docker.sock from one of the containers and tried it then, and none are being triggered now. So I'm assuming that the shared docker socket triggers all containers instead of it being limited to the containers in the compose file.

[m90]

This is expected, Docker does consider all containers on a host equal, no matter how you started them. You can use BACKUP_EXEC_LABEL to work around this and scope your commands to your compose stacks.

[hendrikVandeput]

allright this took some figuring out but eventually it was really easy. Thank you!