How to check if docker daemon is running?

Question

I am trying to create a bash utility script to check if a docker daemon is running in my server. Is there a better way of checking if the docker daemon is running in my serv

Answer 1

I'm sure you want to start the docker daemon so here's the code to start it before executing your Docker run statement:

sudo systemctl start docker

Answer 2

This works for me on Ubuntu

$ systemctl status docker

Answer 3

I made a little Script (Mac Osx) to ensure Docker is running by checking the exit code of docker stats.

#!/bin/bash
#Open Docker, only if is not running
if (! docker stats --no-stream ); then
  # On Mac OS this would be the terminal command to launch Docker
  open /Applications/Docker.app
 #Wait until Docker daemon is running and has completed initialisation
while (! docker stats --no-stream ); do
  # Docker takes a few seconds to initialize
  echo "Waiting for Docker to launch..."
  sleep 1
done
fi

#Start the Container..

Answer 4

You have a utility called pgrep on almost all the Linux systems.

You can just do:

pgrep -f docker > /dev/null || echo "starting docker"

Replace the echo command with your docker starting command.

Answer 5

You could also just check for the existence of /var/run/docker.pid.

Answer 6

The following works on macOS and on Windows if git bash is installed. On macOS open /Applications/Docker.app would start the docker deamon. Haven't seen anything similar for Windows however.

## check docker is running at all
## based on https://stackoverflow.com/questions/22009364/is-there-a-try-catch-command-in-bash
{
  ## will throw an error if the docker daemon is not running and jump
  ## to the next code chunk     
  docker ps -q
} || {
  echo "Docker is not running. Please start docker on your computer"
  echo "When docker has finished starting up press [ENTER} to continue"
  read
}