Restarting an unhealthy docker container based on healthcheck

Question

I am using Docker version 17.09.0-ce, and I see that containers are marked as unhealthy. Is there an option to get the container restart instead of keeping the cont

Answer 1

Docker has a couple of ways to get details on container health. You can configure health checks and how often they run. Also, health checks can be run on applications running inside a container, like http (this would use curl --fail option.) You can view the health_status event to get details.

For detailed information on an unhealthy container the inspect command comes in handy, docker inspect --format='{{json .State.Health}}' container-name (see https://blog.newrelic.com/2016/08/24/docker-health-check-instruction/ for more details.)

You should resolve the error condition causing the "unhealthy" tag (anytime the health check command runs and gets an exit code of 1) first. This may or may not require that Docker restart the container, depending on the error. If you are starting/restarting your containers automatically, then either trapping the start errors or logging them and the health check status can help address errors quickly. Check the link if you are interested in auto start.