Contents
How to automatically update swarm services when the Docker engine?
I’ve seen cases where the restart policy enforced by the docker engine, and the implicit reconciliation in swarm mode have conflicted and resulted in issues. The restart policy would also restart the stopped container which would implicitly break the goal to use a new image since the image can not change for the life of a container.
How many containers per replica in Docker Swarm?
By default, we leave the most recent 5 containers per replica in place to aid troubleshooting (for example, providing the ability to execute a shell in one of these containers and inspect logs). This is a configurable setting, so you could set the number of containers to retain to 0 with docker swarm update –task-history-limit 0.
Is it safe to remove containers on swarm service?
Note that it will cause exited or failed tasks not to show up in docker service ps, since those entries are removed when the containers are cleaned up. cc @sfsmithcha – not sure if this is well-documented. @igrcic Note that it is also safe to remove exited containers manually.
When does a restart policy take effect in Docker?
A restart policy only takes effect after a container starts successfully. In this case, starting successfully means that the container is up for at least 10 seconds and Docker has started monitoring it.
When to restart a container in Docker daemon?
Always restart the container if it stops. If it is manually stopped, it is restarted only when Docker daemon restarts or the container itself is manually restarted. (See the second bullet listed in restart policy details)
How to lock and unlock a Docker Swarm buildvirtual?
To unlock a swarm manager after it restarts, run the `docker swarm unlock` command and provide the following key: SWMKEY-1-WdfH/IX284+lRcXuoVfejiow33HJEKY13MIHX+tTt8 Ensure the key is stored in a very safe place, such as your password repository. It will be needed when the docker manager restarts and you then need to unlock the swarm.
Which is the CLI Command for updating services in Docker?
The Docker CLI command for updating services is the docker service update command. It provides a bewildering array of config options, which allows a user to update just about every configurable aspect of a service. In addition to the configurable aspects of a service, the manner in which the services are updated is also highly configurable.