Running Jenkins master and slaves in a Kubernetes cluster

Kubernetes examples running Jenkins master and slaves

Creating a cluster

Local with Docker Compose

A local testing cluster with one node can be created with Docker Compose

docker-compose up

When using boot2docker or Docker Engine with a remote host, the remote Kubernetes API can be exposed with docker-machine ssh MACHINE_NAME -L 0.0.0.0:8080:localhost:8080 or boot2docker ssh -L 0.0.0.0:8080:localhost:8080

More info

• Docker CookBook examples
• Kubernetes Getting started with Docker

Google Compute Engine

export KUBERNETES_HOME=~/kubernetes
export KUBERNETES_PROVIDER=gce
export KUBERNETES_NUM_MINIONS=2
export KUBE_GCE_ZONE=us-central1-a
$KUBERNETES_HOME/cluster/kube-up.sh

Creating the pods and services

GKE

gcloud compute disks create --size 20GB jenkins-data-disk
kubectl get nodes
kubectl create -f jenkins-master-gke.yml
kubectl get rc
kubectl get pods
kubectl create -f service-gke.yml
kubectl get services
kubectl create -f jenkins-slaves.yml
kubectl get rc
kubectl get pods
kubectl scale replicationcontrollers --replicas=2 jenkins-slave
kubectl describe services/jenkins
gcloud compute forwarding-rules list

AWS

This assumes a working kubernetes installation. I generate mine with kops. If kubectl cluster-info gives you output about the location of the API server, you are likely in pretty good shape. Next, create the working volume for jenkins: `aws ec2 create-volume --availability-zone us-east-1a --size 20 --volume-type gp2

You'll get a response back that looks something like this:

{
    "AvailabilityZone": "us-east-1a",
    "Encrypted": false,
    "VolumeType": "gp2",
    "VolumeId": "vol-002d2b99000000000", # Write this value down
    "State": "creating",
    "Iops": 100,
    "SnapshotId": "",
    "CreateTime": "2016-12-24T17:39:34.725Z",
    "Size": 20
}

Edit jenkins-master-aws.yml and put the VolumeID in the volumeID field`.

kubectl create -f jenkins-master-aws.yml
kubectl get rc
kubectl get pods
kubectl create -f service-aws.yml
kubectl get services
kubectl describe service jenkins
kubectl create -f jenkins-slaves.yml
kubectl get rc
kubectl get pods
kubectl scale replicationcontrollers --replicas=2 jenkins-slave
kubectl describe services/jenkins

These instructions get you a publically accessible Jenkins dashboard at the load balancer specified in kubectl describe service jenkins. This is likely not ideal for a production environment for a number of reasons to be explored at some future date.

Vagrant

kubectl get nodes
kubectl create -f jenkins-master-vagrant.yml
kubectl get rc
kubectl get pods
kubectl create -f service-vagrant.yml
kubectl get services
kubectl describe services/jenkins
kubectl create -f jenkins-slaves.yml
kubectl get rc
kubectl get pods
kubectl scale replicationcontrollers --replicas=2 jenkins-slave

Rolling update

kubectl rolling-update jenkins-slave --update-period=10s -f replication-v2.yml

Tearing down

kubectl stop replicationcontrollers jenkins-slave
kubectl stop replicationcontrollers jenkins
kubectl delete services jenkins
$KUBERNETES_HOME/cluster/kube-down.sh

Demo

Kubernetes cluster up

Jenkins master and slaves provisioning

Kubernetes cluster teardown