title: Jenkins Pipeline - Cannot connect to the Docker daemon
body: <p>I am following this tutorial to build a hello-world maven java app with jenkins in dockers: 
  <a href="https://jenkins.io/doc/tutorials/building-a-java-app-with-maven/#fork-and-clone-the-sample-repository-on-github" rel="nofollow noreferrer">https://jenkins.io/doc/tutorials/building-a-java-app-with-maven/#fork-and-clone-the-sample-repository-on-github</a></p>
  
  <p>This is my app (just fork form the tutorial): <a href="https://github.com/1412108/simple-java-maven-app" rel="nofollow noreferrer">simple-java-maven-app</a></p>
  
  <p>It has a small difference that I used remote repo (Github) not a local repo (or host repo) in Pipeline's option (Repository URL). I pushed Jenkinsfile to repo then build hello-world app with Pipeline.</p>
  
  <pre><code>// Jenkinsfile for Pipeline
  pipeline {
      agent {
          docker {
              image 'maven:3-alpine' 
              args '-v /root/.m2:/root/.m2' 
          }
      }
      stages {
          stage('Build') { 
              steps {
                  sh 'mvn -B -DskipTests clean package' 
              }
          }
      }
  }
  </code></pre>
  
  <p>I got this <a href="https://i.stack.imgur.com/eh83Q.png" rel="nofollow noreferrer">error</a> below and can not find any solution for it. I using Windows 10.</p>
  
  <pre><code>docker pull maven:3-alpine
  Warning: failed to get default registry endpoint from daemon (Cannot connect to the Docker daemon. Is the docker daemon running on this host?). Using system default: https://index.docker.io/v1/
  Cannot connect to the Docker daemon. Is the docker daemon running on this host?
  </code></pre>
  
  <p>Thanks everyone. </p>