title: How to fix "process apparently never started in ..." error in Jenkins pipeline?
body: <p>I am getting the strange error below in my Jenkins pipeline</p>
  <pre><code>[Pipeline] withDockerContainer
  acp-ci-ubuntu-test does not seem to be running inside a container
  $ docker run -t -d -u 1002:1006 -u ubuntu --net=host -v /var/run/docker.sock:/var/run/docker.sock -v /home/ubuntu/.docker:/home/ubuntu/.docker -w /home/ubuntu/workspace/CD-acp-cassandra -v /home/ubuntu/workspace/CD-acp-cassandra:/home/ubuntu/workspace/CD-acp-cassandra:rw,z -v /home/ubuntu/workspace/CD-acp-cassandra@tmp:/home/ubuntu/workspace/CD-acp-cassandra@tmp:rw,z -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** quay.io/arubadevops/acp-build:ut-build cat
  $ docker top 83d04d0a3a3f9785bdde3932f55dee36c079147eb655c1ee9d14f5b542f8fb44 -eo pid,comm
  [Pipeline] {
  [Pipeline] sh
  process apparently never started in /home/ubuntu/workspace/CD-acp-cassandra@tmp/durable-70b242d1
  (running Jenkins temporarily with -Dorg.jenkinsci.plugins.durabletask.BourneShellScript.LAUNCH_DIAGNOSTICS=true might make the problem clearer)
  [Pipeline] }
  $ docker stop --time=1 83d04d0a3a3f9785bdde3932f55dee36c079147eb655c1ee9d14f5b542f8fb44
  $ docker rm -f 83d04d0a3a3f9785bdde3932f55dee36c079147eb655c1ee9d14f5b542f8fb44
  [Pipeline] // withDockerContainer
  </code></pre>
  <p>The corresponding stage in Jenkins pipeline is</p>
  <pre><code>
      stage(&quot;Build docker containers &amp; coreupdate packages&quot;) {
          agent {
              docker {
                  image &quot;quay.io/arubadevops/acp-build:ut-build&quot;
                  label &quot;acp-ci-ubuntu&quot;
                  args &quot;-u ubuntu --net=host -v /var/run/docker.sock:/var/run/docker.sock -v $HOME/.docker:/home/ubuntu/.docker&quot;
                }
            }
            steps {
                script {
                   try {
                      sh &quot;export CI_BUILD_NUMBER=${currentBuild.number}; cd docker; ./build.sh; cd ../test; ./build.sh;&quot;
                      ciBuildStatus=&quot;PASSED&quot;
                   } catch (err) {
                      ciBuildStatus=&quot;FAILED&quot;
                   }
                }
            }
        }
  
  </code></pre>
  <p>What could be the reasons why the process is not getting started within the docker container? Any pointers on how to debug further are also helpful.</p>