<p>I'm running a jenkins instance on GCE inside a docker container and would like to execute a multibranch pipeline from this Jenkinsfile and Github. I'm using the <a href="https://cloud.google.com/solutions/continuous-delivery-jenkins-container-engine" rel="nofollow noreferrer">GCE jenkins</a> tutorial for this. Here is my <code>Jenkinsfile</code> </p>

<pre><code>node {
  def project = 'xxxxxx'
  def appName = 'gceme'
  def feSvcName = "${appName}-frontend"
  def imageTag = "eu.gcr.io/${project}/${appName}:${env.BRANCH_NAME}.${env.BUILD_NUMBER}"

  checkout scm

  sh("echo Build image")
  stage 'Build image'
  sh("docker build -t ${imageTag} .")

  sh("echo Run Go tests")
  stage 'Run Go tests'
  sh("docker run ${imageTag} go test")

  sh("echo Push image to registry")
  stage 'Push image to registry'
  sh("gcloud docker push ${imageTag}")

  sh("echo Deploy Application")
  stage "Deploy Application"
  switch (env.BRANCH_NAME) {
    // Roll out to canary environment
    case "canary":
        // Change deployed image in canary to the one we just built
        sh("sed -i.bak 's#eu.gcr.io/cloud-solutions-images/gceme:1.0.0#${imageTag}#' ./k8s/canary/*.yaml")
        sh("kubectl --namespace=production apply -f k8s/services/")
        sh("kubectl --namespace=production apply -f k8s/canary/")
        sh("echo http://`kubectl --namespace=production get service/${feSvcName} --output=json | jq -r '.status.loadBalancer.ingress[0].ip'` &gt; ${feSvcName}")
        break

    // Roll out to production
    case "master":
        // Change deployed image in canary to the one we just built
        sh("sed -i.bak 's#eu.gcr.io/cloud-solutions-images/gceme:1.0.0#${imageTag}#' ./k8s/production/*.yaml")
        sh("kubectl --namespace=production apply -f k8s/services/")
        sh("kubectl --namespace=production apply -f k8s/production/")
        sh("echo http://`kubectl --namespace=production get service/${feSvcName} --output=json | jq -r '.status.loadBalancer.ingress[0].ip'` &gt; ${feSvcName}")
        break

    // Roll out a dev environment
    default:
        // Create namespace if it doesn't exist
        sh("kubectl get ns ${env.BRANCH_NAME} || kubectl create ns ${env.BRANCH_NAME}")
        // Don't use public load balancing for development branches
        sh("sed -i.bak 's#LoadBalancer#ClusterIP#' ./k8s/services/frontend.yaml")
        sh("sed -i.bak 's#eu.gcr.io/cloud-solutions-images/gceme:1.0.0#${imageTag}#' ./k8s/dev/*.yaml")
        sh("kubectl --namespace=${env.BRANCH_NAME} apply -f k8s/services/")
        sh("kubectl --namespace=${env.BRANCH_NAME} apply -f k8s/dev/")
        echo 'To access your environment run `kubectl proxy`'
        echo "Then access your service via http://localhost:8001/api/v1/proxy/namespaces/${env.BRANCH_NAME}/services/${feSvcName}:80/"
  }
}
</code></pre>

<p>I always get an error <code>docker not found</code>:</p>

<pre><code>[apiservice_master-GJCRJX6ZJPDVVSEUHIS6VBX7OYMFS5WKRVRKCSF4PSO76ZGZPKFQ] Running shell script
+ docker build -t eu.gcr.io/xxxxx/apiservice:master.1 .
/var/jenkins_home/workspace/apiservice_master-GJCRJX6ZJPDVVSEUHIS6VBX7OYMFS5WKRVRKCSF4PSO76ZGZPKFQ@tmp/durable-b4503ecc/script.sh: 2: /var/jenkins_home/workspace/apiservice_master-GJCRJX6ZJPDVVSEUHIS6VBX7OYMFS5WKRVRKCSF4PSO76ZGZPKFQ@tmp/durable-b4503ecc/script.sh: docker: not found
</code></pre>

<p>What do I have to change to make docker work inside jenkins?</p>

<p>That looks like DiD (Docker in Docker), which this <a href="https://forums.docker.com/t/docker-not-found-in-jenkins-pipeline/31683" rel="nofollow noreferrer">recent issue</a> points out as problematic.<br>
See "<a href="http://jpetazzo.github.io/2015/09/03/do-not-use-docker-in-docker-for-ci/" rel="nofollow noreferrer">Using Docker-in-Docker for your CI or testing environment? Think twice.</a>"</p>

<p>That same issue recommends to run in privilege mode.<br>
And make sure your docker container in which you are executing does have docker installed.</p>
