Adding Jenkins to on premises Kubernetes cluster via Helm

The following is part of a series of posts I wrote called "Repurposing old equipment by building a Kubernetes cluster".

While old equipment by itself is in general not very useful unless you find a particular use case, by combining a number of old devices you can build a more powerful system that can span perhaps a number of use cases. Kubernetes is a perfect candidate to be able to do this. I had a number of old laptops laying about and decided to test this theory out.

Use cases for a cluster made up of old equipment such as what I’ve built so far definitely does not include mission critical, production based tasks.

One definite use case though is your own (or your companies) CI/CD system. The costs associated with such systems is typically pretty high compared to the use they get and the higher than required uptime / SLA that come with most cloud servers these days.

Jenkins is obviously the clear choice here, so I install it via Helm with the following:

$ helm install --name jenkins stable/jenkins --set master.serviceType=ClusterIP
NAME:   jenkins
LAST DEPLOYED: Thu Sep  5 18:46:41 2019
NAMESPACE: default
STATUS: DEPLOYED

RESOURCES:
==> v1/ConfigMap
NAME           DATA  AGE
jenkins        5     2s
jenkins-tests  1     2s

==> v1/Deployment
NAME     READY  UP-TO-DATE  AVAILABLE  AGE
jenkins  0/1    1           0          1s

==> v1/PersistentVolumeClaim
NAME     STATUS  VOLUME                                    CAPACITY  ACCESS MODES  STORAGECLASS  AGE
jenkins  Bound   pvc-34f5a881-8f72-428c-a40e-523b0192f283  8Gi       RWO           nfs-sc        2s

==> v1/Pod(related)
NAME                      READY  STATUS    RESTARTS  AGE
jenkins-6f7b667cd5-5n8hv  0/1    Init:0/1  0         1s

==> v1/Role
NAME                     AGE
jenkins-schedule-agents  2s

==> v1/RoleBinding
NAME                     AGE
jenkins-schedule-agents  1s

==> v1/Secret
NAME     TYPE    DATA  AGE
jenkins  Opaque  2     2s

==> v1/Service
NAME           TYPE       CLUSTER-IP     EXTERNAL-IP  PORT(S)    AGE
jenkins        ClusterIP  10.101.45.203  <none>       8080/TCP   1s
jenkins-agent  ClusterIP  10.103.178.0   <none>       50000/TCP  1s

==> v1/ServiceAccount
NAME     SECRETS  AGE
jenkins  1        2s


NOTES:
1. Get your 'admin' user password by running:
  printf $(kubectl get secret --namespace default jenkins -o jsonpath="{.data.jenkins-admin-password}" | base64 --decode);echo
2. Get the Jenkins URL to visit by running these commands in the same shell:
  export POD_NAME=$(kubectl get pods --namespace default -l "app.kubernetes.io/component=jenkins-master" -l "app.kubernetes.io/instance=jenkins" -o jsonpath="{.items[0].metadata.name}")
  echo http://127.0.0.1:8080
  kubectl --namespace default port-forward $POD_NAME 8080:8080

3. Login with the password from step 1 and the username: admin


For more information on running Jenkins on Kubernetes, visit:
https://cloud.google.com/solutions/jenkins-on-container-engine

I now forward the port for the current pod

$ kubectl port-forward jenkins-6f7b667cd5-5n8hv 8080:8080
Forwarding from 127.0.0.1:8080 -> 8080
Forwarding from [::1]:8080 -> 8080

And then visit http://localhost:8080 and Jenkins login screen appears. Fantastic!

Jenkins Login

Another example of how easy Kubernetes and Helm make things. You couldn’t deploy a scalable version of Jenkins much quicker than what I just did.

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