[FIXED] Running Jenkins on docker container.Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

Issue

I am running jenkins inside docker container(jenkins/jenkins:lts) as a base image.

I have created a pipeline in jenkins where i have added the following

node{
    stage('SCM checkout')
    {
        git url: 'https://github.com/THIYAGU22/javaapp'
    }
    stage('Mvn Package')
    {
        def mvnHome = tool name: 'maven-3', type: 'maven'
        def mvnCMD = "${mvnHome}/bin/mvn"
        sh script: "${mvnCMD} clean package"
    }
    stage('Build Docker Image')
    {
        tool name: 'docker', type: 'dockerTool'
        def dockerHome = tool 'docker'
        env.PATH = "${dockerHome}/bin:${env.PATH}"
        sh 'docker build -t imthiyagu/java-app-2.0.0 .'
    }
}

After the build it can able to process SCM checkout and Mvn package but not building docker image

Any help? Thanks

Solution

The docker command needs a Docker socket to talk to. The default socket it looks for is /var/run/docker.sock. You have two options of providing a Docker socket:

1. Run the Jenkins image with the --privileged -v /var/run/docker.sock:/var/run/docker.sock arguments. This mounts the host's Docker socket into the Jenkins image, which can then be used by Docker. Note that using --privileged is a security risk.

2. Expose your host's Docker socket over HTTPS: https://docs.docker.com/engine/security/https/. Then set the DOCKER_HOST environment variable pointing to tcp://YOURHOST:PORT, where port is 2375 or 2376.

Answered By - Joep Weijers
Answer Checked By - Dawn Plyler (JavaFixing Volunteer)