Offline agent when creating a Kubernetes pod template using Jenkins scripted pipeline - jenkins

Question

I have created a shared library and it has a groovy file named myBuildPlugin.groovy:
def label = "worker-${UUID.randomUUID().toString()}"
podTemplate(label: label, yaml: """
apiVersion: v1
kind: Pod
metadata:
name: my-build
spec:
containers:
- name: jnlp
image: dtr.myhost.com/test/jenkins-build-agent:latest
ports:
- containerPort: 8080
- containerPort: 50000
resources:
limits:
cpu : 1
memory : 1Gi
requests:
cpu: 200m
memory: 256Mi
env:
- name: JENKINS_URL
value: http://jenkins:8080
- name: mongo
image: mongo
ports:
- containerPort: 8080
- containerPort: 50000
- containerPort: 27017
resources:
requests:
cpu: 200m
memory: 256Mi
limits:
cpu: 1
memory: 512Mi
imagePullSecrets:
- name: dtrsecret""")
{
node(label) {
pipelineParams.step1.call([label : label])
}
}
When in my project I use myBuildPlugin as below, the log shows it waits for an executor forever. When I look at Jenkins I can see the agent is being created but for some reason it can't talk to it via port 50000 (or perhaps the pod can't talk to the agent!)
Later I tried to remove yaml and instead used the following code:
podTemplate(label: 'mypod', cloud: 'kubernetes', containers: [
containerTemplate(
name: 'jnlp',
image: 'dtr.myhost.com/test/jenkins-build-agent:latest',
ttyEnabled: true,
privileged: false,
alwaysPullImage: false,
workingDir: '/home/jenkins',
resourceRequestCpu: '1',
resourceLimitCpu: '100m',
resourceRequestMemory: '100Mi',
resourceLimitMemory: '200Mi',
envVars: [
envVar(key: 'JENKINS_URL', value: 'http://jenkins:8080'),
]
),
containerTemplate(name: 'maven', image: 'maven:3.5.0', command: 'cat', ttyEnabled: true),
containerTemplate(name: 'docker', image: 'docker', command: 'cat', ttyEnabled: true)
],
volumes: [
emptyDirVolume(mountPath: '/etc/mount1', memory: false),
hostPathVolume(mountPath: '/var/run/docker.sock', hostPath: '/var/run/docker.sock')
],
imagePullSecrets: [ 'dtrsecret' ],
)
{
node(label) {
pipelineParams.step1.call([label : label])
}
}
Still no luck. Interestingly if I define all these containers in Jenkins configuration, things work smoothly. This is my configuration:
and this is the pod template configuration:
It appears that if I change the label to something other that jenkins-jenkins-slave the issue happens. This is the case even if it's defined via Jenkins' configuration page. If that's the case, how am I suppose to create multiple Pod template for different type of projects?
Just today, I also tried to use pod inheritance as below without any success:
def label = 'kubepod-test'
podTemplate(label : label, inheritFrom : 'default',
containers : [
containerTemplate(name : 'mongodb', image : 'mongo', command : '', ttyEnabled : true)
]
)
{
node(label) {
}
}
Please help me on this issue. Thanks

Answer 1

There's something iffy about your pod configuration, you can't have your Jenkins and Mongo containers using the same port 50000. Generally, you want to specify a unique port since pods share the same port space.
In this case looks like you need port 50000 to set up a tunnel to the Jenkins agent. Keep in mind that the Jenkins plugin might be doing other things such as setting up a Kubernetes Service or using the internal Kubernetes DNS.
In the second example, I don't even see port 50000 exposed.