title: Jenkins instance is missing
body: <p>I'm trying to create a quicklab on GCP to implement CI/CD with Jenkins on GKE, I created a <strong>Multibranch Pipeline</strong>. When I push the modified script  to git, Jenkins kicks off a build and fails with the following error:</p>
  
  <blockquote>
  <pre><code>    Branch indexing
       &gt; git rev-parse --is-inside-work-tree # timeout=10
      Setting origin to https://source.developers.google.com/p/qwiklabs-gcp-gcpd-502b5f86f641/r/default
       &gt; git config remote.origin.url https://source.developers.google.com/p/qwiklabs-gcp-gcpd-502b5f86f641/r/default # timeout=10
      Fetching origin...
      Fetching upstream changes from origin
       &gt; git --version # timeout=10
       &gt; git config --get remote.origin.url # timeout=10
      using GIT_ASKPASS to set credentials qwiklabs-gcp-gcpd-502b5f86f641
       &gt; git fetch --tags --progress -- origin +refs/heads/*:refs/remotes/origin/*
      Seen branch in repository origin/master
      Seen branch in repository origin/new-feature
      Seen 2 remote branches
      Obtained Jenkinsfile from 4bbac0573482034d73cee17fa3de8999b9d47ced
      Running in Durability level: MAX_SURVIVABILITY
      [Pipeline] Start of Pipeline
      [Pipeline] podTemplate
      [Pipeline] {
      [Pipeline] node
      Still waiting to schedule task
      Waiting for next available executor
      Agent sample-app-f7hdx-n3wfx is provisioned from template Kubernetes Pod Template
      ---
      apiVersion: "v1"
      kind: "Pod"
      metadata:
        annotations:
          buildUrl: "http://cd-jenkins:8080/job/sample-app/job/new-feature/1/"
        labels:
          jenkins: "slave"
          jenkins/sample-app: "true"
        name: "sample-app-f7hdx-n3wfx"
      spec:
        containers:
        - command:
          - "cat"
          image: "gcr.io/cloud-builders/kubectl"
          name: "kubectl"
          tty: true
          volumeMounts:
          - mountPath: "/home/jenkins/agent"
            name: "workspace-volume"
            readOnly: false
        - command:
          - "cat"
          image: "gcr.io/cloud-builders/gcloud"
          name: "gcloud"
          tty: true
          volumeMounts:
          - mountPath: "/home/jenkins/agent"
            name: "workspace-volume"
            readOnly: false
        - command:
          - "cat"
          image: "golang:1.10"
          name: "golang"
          tty: true
          volumeMounts:
          - mountPath: "/home/jenkins/agent"
            name: "workspace-volume"
            readOnly: false
        - env:
          - name: "JENKINS_SECRET"
            value: "********"
          - name: "JENKINS_TUNNEL"
            value: "cd-jenkins-agent:50000"
          - name: "JENKINS_AGENT_NAME"
            value: "sample-app-f7hdx-n3wfx"
          - name: "JENKINS_NAME"
            value: "sample-app-f7hdx-n3wfx"
          - name: "JENKINS_AGENT_WORKDIR"
            value: "/home/jenkins/agent"
          - name: "JENKINS_URL"
            value: "http://cd-jenkins:8080/"
          image: "jenkins/jnlp-slave:alpine"
          name: "jnlp"
          volumeMounts:
          - mountPath: "/home/jenkins/agent"
            name: "workspace-volume"
            readOnly: false
        nodeSelector: {}
        restartPolicy: "Never"
        serviceAccountName: "cd-jenkins"
        volumes:
        - emptyDir: {}
          name: "workspace-volume"
  
      Running on sample-app-f7hdx-n3wfx in /home/jenkins/agent/workspace/sample-app_new-feature
      [Pipeline] {
      [Pipeline] stage
      [Pipeline] { (Declarative: Checkout SCM)
      [Pipeline] checkout
      [Pipeline] }
      [Pipeline] // stage
      [Pipeline] }
      [Pipeline] // node
      [Pipeline] }
      [Pipeline] // podTemplate
      [Pipeline] End of Pipeline
      java.lang.IllegalStateException: Jenkins.instance is missing. Read the documentation of Jenkins.getInstanceOrNull to see what you are
  doing wrong.
        at jenkins.model.Jenkins.get(Jenkins.java:772)
        at hudson.model.Hudson.getInstance(Hudson.java:77)
        at com.google.jenkins.plugins.source.GoogleRobotUsernamePassword.areOnMaster(GoogleRobotUsernamePassword.java:146)
        at com.google.jenkins.plugins.source.GoogleRobotUsernamePassword.readObject(GoogleRobotUsernamePassword.java:180)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1170)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2178)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2069)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1573)
        at java.io.ObjectInputStream.readArray(ObjectInputStream.java:1975)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)
        at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2287)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2211)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2069)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1573)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:431)
        at hudson.remoting.UserRequest.deserialize(UserRequest.java:290)
        at hudson.remoting.UserRequest.perform(UserRequest.java:189)
      Also:   hudson.remoting.Channel$CallSiteStackTrace: Remote call to JNLP4-connect connection from 10.8.2.12/10.8.2.12:53086
            at hudson.remoting.Channel.attachCallSiteStackTrace(Channel.java:1743)
            at hudson.remoting.UserRequest$ExceptionResponse.retrieve(UserRequest.java:357)
            at hudson.remoting.Channel.call(Channel.java:957)
            at hudson.remoting.RemoteInvocationHandler.invoke(RemoteInvocationHandler.java:283)
            at com.sun.proxy.$Proxy88.addCredentials(Unknown Source)
            at org.jenkinsci.plugins.gitclient.RemoteGitImpl.addCredentials(RemoteGitImpl.java:200)
            at hudson.plugins.git.GitSCM.createClient(GitSCM.java:845)
            at hudson.plugins.git.GitSCM.createClient(GitSCM.java:813)
            at hudson.plugins.git.GitSCM.checkout(GitSCM.java:1186)
            at org.jenkinsci.plugins.workflow.steps.scm.SCMStep.checkout(SCMStep.java:124)
            at org.jenkinsci.plugins.workflow.steps.scm.SCMStep$StepExecutionImpl.run(SCMStep.java:93)
            at org.jenkinsci.plugins.workflow.steps.scm.SCMStep$StepExecutionImpl.run(SCMStep.java:80)
            at org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution.lambda$start$0(SynchronousNonBlockingStepExecution.java:47)
            at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
            at java.util.concurrent.FutureTask.run(FutureTask.java:266)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
      Caused: java.lang.Error: Failed to deserialize the Callable object.
        at hudson.remoting.UserRequest.perform(UserRequest.java:195)
        at hudson.remoting.UserRequest.perform(UserRequest.java:54)
        at hudson.remoting.Request$2.run(Request.java:369)
        at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:72)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at hudson.remoting.Engine$1.lambda$newThread$0(Engine.java:97)
      Caused: java.io.IOException: Remote call on JNLP4-connect connection from 10.8.2.12/10.8.2.12:53086 failed
        at hudson.remoting.Channel.call(Channel.java:963)
        at hudson.remoting.RemoteInvocationHandler.invoke(RemoteInvocationHandler.java:283)
      Caused: hudson.remoting.RemotingSystemException
        at hudson.remoting.RemoteInvocationHandler.invoke(RemoteInvocationHandler.java:299)
        at com.sun.proxy.$Proxy88.addCredentials(Unknown Source)
        at org.jenkinsci.plugins.gitclient.RemoteGitImpl.addCredentials(RemoteGitImpl.java:200)
        at hudson.plugins.git.GitSCM.createClient(GitSCM.java:845)
        at hudson.plugins.git.GitSCM.createClient(GitSCM.java:813)
        at hudson.plugins.git.GitSCM.checkout(GitSCM.java:1186)
        at org.jenkinsci.plugins.workflow.steps.scm.SCMStep.checkout(SCMStep.java:124)
        at org.jenkinsci.plugins.workflow.steps.scm.SCMStep$StepExecutionImpl.run(SCMStep.java:93)
        at org.jenkinsci.plugins.workflow.steps.scm.SCMStep$StepExecutionImpl.run(SCMStep.java:80)
        at org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution.lambda$start$0(SynchronousNonBlockingStepExecution.java:47)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)
      Finished: FAILURE
  </code></pre>
  </blockquote>
  
  <pre><code>
  </code></pre>