<p>I'm using the Kubernetes Jenkins plugin in order to create Jenkins slaves on demand. The slaves job is to deploy and provision my apps to the Kubernetes cluster.</p>

<p>I created a pipeline project and wrote a very simple Jenkinsfile:</p>

<pre><code>podTemplate(label: 'jenkins-pipeline', containers: [
containerTemplate(name: 'jnlp', image: 'lachlanevenson/jnlp-slave:3.10-1-alpine', args: '${computer.jnlpmac} ${computer.name}', workingDir: '/home/jenkins', resourceRequestCpu: '200m', resourceLimitCpu: '300m', resourceRequestMemory: '256Mi', resourceLimitMemory: '512Mi'),
containerTemplate(name: 'helm', image: 'lachlanevenson/k8s-helm:v2.6.0', command: 'cat', ttyEnabled: true),
containerTemplate(name: 'kubectl', image: 'lachlanevenson/k8s-kubectl:v1.4.8', command: 'cat', ttyEnabled: true),
containerTemplate(name: 'curl', image: 'appropriate/curl:latest', command: 'cat', ttyEnabled: true)
],
volumes:[
    hostPathVolume(mountPath: '/var/run/docker.sock', hostPath: 
'/var/run/docker.sock'),
]){

node ('jenkins-pipeline') {

def pwd = pwd()
def chart_dir = "${pwd}/chart"

checkout([$class: 'SubversionSCM', additionalCredentials: [], excludedCommitMessages: '', excludedRegions: '', excludedRevprop: '', excludedUsers: '', filterChangelog: false, ignoreDirPropChanges: false, includedRegions: '', locations: [[credentialsId: '4041436e-e9dc-4060-95d5-b28be47b1a14', depthOption: 'infinity', ignoreExternalsOption: true, local: '.', remote: 'https://svn.project.com/repo/trunk/RnD/dev/server/src/my-app']], workspaceUpdater: [$class: 'CheckoutUpdater']])

stage ('deploy canary to k8s') {
  container('helm') {
    def version = params.${VERSION}
    def environment = params.${ENVIRONMENT}
    // Deploy using Helm chart

    sh "helm upgrade --install ${version} ${chart_dir} --set imageTag=${version},replicas=1,environment=${environment} --namespace=dev"  

      }
    }
  }
}
</code></pre>

<p>The Jenkins slave spins up on Kubernetes but the job fails with this stack trace:</p>

<pre><code>[Pipeline] stage
[Pipeline] { (deploy canary to k8s)
[Pipeline] container
[Pipeline] {
[Pipeline] }
[Pipeline] // container
[Pipeline] }
[Pipeline] // stage
[Pipeline] }
[Pipeline] // node
[Pipeline] }
[Pipeline] // podTemplate
[Pipeline] End of Pipeline
hudson.remoting.ProxyException: groovy.lang.MissingMethodException: No signature of method: java.util.Collections$UnmodifiableMap.$() is applicable for argument types: (org.jenkinsci.plugins.workflow.cps.CpsClosure2) values: [org.jenkinsci.plugins.workflow.cps.CpsClosure2@7d7d26fa]
Possible solutions: is(java.lang.Object), any(), get(java.lang.Object), any(groovy.lang.Closure), max(groovy.lang.Closure), min(groovy.lang.Closure)
    at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.unwrap(ScriptBytecodeAdapter.java:58)
    at org.codehaus.groovy.runtime.callsite.PojoMetaClassSite.call(PojoMetaClassSite.java:49)
    at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
    at com.cloudbees.groovy.cps.sandbox.DefaultInvoker.methodCall(DefaultInvoker.java:18)
    at WorkflowScript.run(WorkflowScript:20)
    at ___cps.transform___(Native Method)
    at com.cloudbees.groovy.cps.impl.ContinuationGroup.methodCall(ContinuationGroup.java:57)
    at com.cloudbees.groovy.cps.impl.FunctionCallBlock$ContinuationImpl.dispatchOrArg(FunctionCallBlock.java:109)
    at com.cloudbees.groovy.cps.impl.FunctionCallBlock$ContinuationImpl.fixArg(FunctionCallBlock.java:82)
    at sun.reflect.GeneratedMethodAccessor512.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.cloudbees.groovy.cps.impl.ContinuationPtr$ContinuationImpl.receive(ContinuationPtr.java:72)
    at com.cloudbees.groovy.cps.impl.ClosureBlock.eval(ClosureBlock.java:46)
    at com.cloudbees.groovy.cps.Next.step(Next.java:74)
    at com.cloudbees.groovy.cps.Continuable.run0(Continuable.java:154)
    at org.jenkinsci.plugins.workflow.cps.CpsThread.runNextChunk(CpsThread.java:165)
    at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.run(CpsThreadGroup.java:328)
    at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.access$100(CpsThreadGroup.java:80)
    at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:240)
    at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:228)
    at org.jenkinsci.plugins.workflow.cps.CpsVmExecutorService$2.call(CpsVmExecutorService.java:64)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at hudson.remoting.SingleLaneExecutorService$1.run(SingleLaneExecutorService.java:112)
    at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:28)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:748)
Finished: FAILURE
</code></pre>

<p>I understand that the error comes from a type mismatch but I'm having a hard time understanding in which part of the Jenkinsfile and what I should do about it.</p>

<p>Can anyone please help me?</p>

<p>This</p>

<pre><code>def version = params.${VERSION}
def environment = params.${ENVIRONMENT}
</code></pre>

<p>Should be this</p>

<pre><code>def version = params."${VERSION}"
def environment = params."${ENVIRONMENT}"
</code></pre>
