how to run docker commands inside jenkins pipeline jobs

Question

In my Manage Jenkins > Global Tool Configuration, i have already configured a tool called "docker" as follows:

name:                   docker
install automatically:  CHECKED
docker version:         latest

Then all I have in my jenkinsfile is the following and nothing else:

node {
    DOCKER_HOME = tool "docker"
    sh """
        echo $DOCKER_HOME
        ls $DOCKER_HOME/bin/
        $DOCKER_HOME/bin/docker images
        $DOCKER_HOME/bin/docker ps -a
    """
}

I get an error like this "Cannot connect to the Docker daemon. Is the docker daemon running on this host?".

Following is the full console log:

Started by user Syed Rakib Al Hasan
[Pipeline] node
Running on master in /var/jenkins_home/workspace/helloDocker
[Pipeline] {
[Pipeline] tool
[Pipeline] sh
[helloDocker] Running shell script
+ echo /var/jenkins_home/tools/org.jenkinsci.plugins.docker.commons.tools.DockerTool/docker
/var/jenkins_home/tools/org.jenkinsci.plugins.docker.commons.tools.DockerTool/docker
+ ls /var/jenkins_home/tools/org.jenkinsci.plugins.docker.commons.tools.DockerTool/docker/bin/
docker
+ /var/jenkins_home/tools/org.jenkinsci.plugins.docker.commons.tools.DockerTool/docker/bin/docker images
Cannot connect to the Docker daemon. Is the docker daemon running on this host?
[Pipeline] }
[Pipeline] // node
[Pipeline] End of Pipeline
ERROR: script returned exit code 1
Finished: FAILURE

How do i ensure that the docker daemon/service is running/started before my pipeline reaches the line to run docker commands.

Is there any other native docker-build-step plugin way to achieve what I am doing here? Like docker ps -a or docker images or docker build -t?

Some assumptions:

Let's say my chosen node do not already have docker/docker-engine installed/running in my host machine. That's the purpose of the tool command to automatically install docker in the node if it is not already there.

Answer 1

This Jenkins plugin is for the docker client; I'd solve (work around) by:

• setting up jenkins slaves where docker daemon is reachable, add a label
• setting up a housekeeping job which will fail if docker daemon was not reachable (so we can notify the infra team without having the QA to figure out and escalate the problem)
• assign jobs which assumes the docker daemon to be reachable to this label

I hope it helps, and I'm curious if any of you have a better solution!