Docker Health Check

The command is executed inside the container by the Docker Engine
It expects 0 (OK) or 1 (Error) as output
There are three states that are present for a container : Starting, Healthy, Unhealthy
The command is executed every 30 secs by default

The last 5 health check values can be accesses by inspecting the container
Docker run will not perform an action on an unhealthy container
Services is responsible for replacing an container if its status is unhealthy

docker container run --name p2 -d \
	--health-cmd="pd_isready -U postgres || exit 1" postgres

Some containers can have an inbuild health check command for other we can specify an command that should be executed to consider the container healthy