podTemplate(label: 'mypod', containers: [
    containerTemplate(name: 'maven', image: 'maven:3.3.9-jdk-8-alpine', ttyEnabled: true, command: 'cat'),
    containerTemplate(name: 'jnlp', image: 'jenkinsci/jnlp-slave', args: '${computer.jnlpmac} ${computer.name}'),
]) {

    node ('mypod') {
        stage 'Get a Maven project'
        git 'https://github.com/jenkinsci/kubernetes-plugin.git'
        container('maven') {
            stage 'Build a Maven project'
            sh 'mvn clean install'
        }
    }
}

[kubernetes-plugin-pipeline-example] Running shell script
Executing shell script inside container [maven] of pod [kubernetes-f914ee7f49c44f7eaa182af5fda74c93-60beb1f2a295]
java.net.ProtocolException: Expected HTTP 101 response but was '404 Not Found'
	at com.squareup.okhttp.ws.WebSocketCall.createWebSocket(WebSocketCall.java:123)
	at com.squareup.okhttp.ws.WebSocketCall.access$000(WebSocketCall.java:40)
	at com.squareup.okhttp.ws.WebSocketCall$1.onResponse(WebSocketCall.java:98)
	at com.squareup.okhttp.Call$AsyncCall.execute(Call.java:177)
	at com.squareup.okhttp.internal.NamedRunnable.run(NamedRunnable.java:33)
	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:745)