Hosting Jenkins on a Kubernetes cluster is beneficial for Kubernetes-based DevOps and dynamic container-based scalable Jenkins agents.
what is Jenkins in DevOps?
An open-source automation server that enables developers around the world to reliably build, test, and deploy their software. Jenkins can be used as a simple CI server or turned into the continuous delivery hub for any project.
According to the official site
Why Choose Jenkins for your DevOps?
Continuous Integration and Continuous Delivery
As an extensible automation server, Jenkins can be used as a simple CI server or turned into the continuous delivery hub for any project.
Easy installation
Jenkins is a self-contained Java-based program, ready to run out-of-the-box, with packages for Windows, Linux, macOS and other Unix-like operating systems.
Easy configuration
Jenkins can be easily set up and configured via its web interface, which includes on-the-fly error checks and built-in help.
Extensible
Jenkins can be extended via its plugin architecture, providing nearly infinite possibilities for what Jenkins can do.
Distributed
Jenkins can easily distribute work across multiple machines, helping drive builds, tests and deployments across multiple platforms faster.
Plugins
With hundreds of plugins in the Update Center, Jenkins integrates with practically every tool in the continuous integration and continuous delivery toolchain.
Kubernetes Jenkins Deployment.
Lets get started with deploying Jenkins on Kubernetes.
Create a Namespace
Create a Namespace for Jenkins. It is good to categorize all the devops tools as a separate namespace from other applications.
kubectl create namespace devops-toolsCreate a service account with Kubernetes admin permissions.
Create a serviceAccount.yaml file and copy the following admin service account manifest.
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: jenkins-admin
rules:
- apiGroups: [""]
resources: ["*"]
verbs: ["*"]
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: jenkins-admin
namespace: devops-tools
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: jenkins-admin
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: jenkins-admin
subjects:
- kind: ServiceAccount
name: jenkins-admin
namespace: devops-toolsThe serviceAccount.yaml creates a jenkins-admin clusterRole, jenkins-admin ServiceAccount and binds the clusterRole to the service account.
The jenkins-admin cluster role has all the permissions to manage the cluster components. You can also restrict access by specifying individual resource actions.
Now create the service account using kubectl.
Create a volume.yaml and copy the following persistent volume manifest.
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
name: local-storage
provisioner: kubernetes.io/no-provisioner
volumeBindingMode: WaitForFirstConsumer
---
apiVersion: v1
kind: PersistentVolume
metadata:
name: jenkins-pv-volume
labels:
type: local
spec:
storageClassName: local-storage
claimRef:
name: jenkins-pv-claim
namespace: devops-tools
capacity:
storage: 10Gi
accessModes:
- ReadWriteOnce
local:
path: /mnt
nodeAffinity:
required:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/hostname
operator: In
values:
- worker-node01
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: jenkins-pv-claim
namespace: devops-tools
spec:
storageClassName: local-storage
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 3GiImportant: Replace
Authors Noteworker-node01with any one of your cluster worker nodes hostname.
You can get the worker node hostname using the kubectl.
kubectl get nodesCreate local persistent volume for persistent Jenkins data on Pod restarts.
To create the volume using kubectl
kubectl create -f volume.yamlCreate a deployment YAML and deploy it.
Create a Deployment file named deployment.yaml and copy the following deployment manifest.
Here we are using the latest Jenkins LTS docker image from the Docker hub.
apiVersion: apps/v1
kind: Deployment
metadata:
name: jenkins
namespace: devops-tools
spec:
replicas: 1
selector:
matchLabels:
app: jenkins-server
template:
metadata:
labels:
app: jenkins-server
spec:
securityContext:
fsGroup: 1000
runAsUser: 1000
serviceAccountName: jenkins-admin
containers:
- name: jenkins
image: jenkins/jenkins:lts
resources:
limits:
memory: "2Gi"
cpu: "1000m"
requests:
memory: "500Mi"
cpu: "500m"
ports:
- name: httpport
containerPort: 8080
- name: jnlpport
containerPort: 50000
livenessProbe:
httpGet:
path: "/login"
port: 8080
initialDelaySeconds: 90
periodSeconds: 10
timeoutSeconds: 5
failureThreshold: 5
readinessProbe:
httpGet:
path: "/login"
port: 8080
initialDelaySeconds: 60
periodSeconds: 10
timeoutSeconds: 5
failureThreshold: 3
volumeMounts:
- name: jenkins-data
mountPath: /var/jenkins_home
volumes:
- name: jenkins-data
persistentVolumeClaim:
claimName: jenkins-pv-claimIn this Jenkins Kubernetes deployment we have used the following.
securityContextfor Jenkins pod to be able to write to the local persistent volume.- Liveliness and readiness probe.
- Local persistent volume based on local storage class that holds the Jenkins data path
/var/jenkins_home
Create a service YAML and deploy it.
Create a service.yaml and copy the following service manifest.
apiVersion: v1
kind: Service
metadata:
name: jenkins-service
namespace: devops-tools
annotations:
prometheus.io/scrape: 'true'
prometheus.io/path: /
prometheus.io/port: '8080'
spec:
selector:
app: jenkins-server
type: NodePort
ports:
- port: 8080
targetPort: 8080
nodePort: 32000
We have created a deployment. However, it is not accessible to the outside world. For accessing the Jenkins deployment from the outside world, we should create a service and map it to the deployment.
Note: Here, we are using the type as
NodePortwhich will expose Jenkins on all kubernetes node IPs on port 32000. If you have an ingress setup, you can create an ingress rule to access Jenkins. Also, you can expose the Jenkins service as a Loadbalancer if you are running the cluster on AWS, Google, or Azure cloud.
Create the Jenkins service using kubectl.
kubectl apply -f service.yaml
Access the Jenkins application on a Node Port.
Now if you browse to any one of the Node IPs on port 32000, you will be able to access the Jenkins dashboard.
http://<node-ip>:32000
Jenkins will ask for the initial Admin password when you access the dashbaord for the first time.
You can get that from the pod logs either from the kubernetes dashboard or CLI. You can get the pod details using the following CLI command.
kubectl get pods --namespace=devops-tools
And with the pod name, you can get the logs as shown below. replace the pod name with your pod name.
kubectl logs jenkins-deployment-2539456353-j00w5 --namespace=jenkins
Alternatively, you can run the exec command to get the password directly from the location as show below.
kubectl exec -it jenkins-559d8cd85c-cfcgk cat /var/jenkins_home/secrets/initialAdminPassword -n devops-toolsOnce you enter the password you can proceed installing the suggested plugin and creating a admin user. All these steps are self-explanatory from the Jenkins dashboard.
So, This was Annotating Kubernetes Services For Humans Also, Check New OpenSource Alternative to Datadog?
Check Out Sportsfeed for Sports News, Reviews & More. Shaurya Loans Cityhawk Fauji Farms City Hawks Sports
If you need help with your Website Development or Digital Marketing, discover our Services.
You must be logged in to post a comment.