title: gitlab-runner:Pipeling is pending infinitely
body: <p>I install a Specific Runners,and the status is actived.</p>
  <p>my .gitlab-ci.ymi file code:</p>
  <pre><code>stages:
    - build
  
  build_maven:
    stage: build
    only:
      - master
    script:
      - echo &quot;hello CI/CD&quot;
    tags: 
      - vue-dev-pub
  </code></pre>
  <p>when I push the master branch,the gitlab-runner is running,but it's pending infinitely。</p>
  <p>the job page show:</p>
  <blockquote>
  <h1>This job has not started yet</h1>
  <p>This job is in pending state and is waiting to be picked by a runner</p>
  </blockquote>
  <p>if I excute the runner manually,the job can pass.</p>
  <p>the command of gitlab-runner verify shows:</p>
  <pre><code>Runtime platform                                    arch=amd64 os=linux pid=24616 revision=d0b76032 version=12.0.2
  WARNING: Running in user-mode.                     
  WARNING: The user-mode requires you to manually start builds processing: 
  WARNING: $ gitlab-runner run                       
  WARNING: Use sudo for system-mode:                 
  WARNING: $ sudo gitlab-runner...                   
                                                     
  Verifying runner... is alive                        runner=T4iKvsT3
  
  </code></pre>
  <p>I am waiting for you respond,thanks!</p>