Setup Jenkins on K8s

This is an example Repo containing the necessary Kubernetes-Manifests to get started with Jenkins on K8s. The manifests for the setup are located in the k8s-jenkins-setup-folder.

Create Namespace

First you need to create a namespace.
In this case its named devops-tools if you want to change it, make sure to adjust all the files.

kubectl create ns devops-tools

Adjust Values

You need to adjust the values in service.yaml and volume.yaml based on your preferences.
Especially, the hostname of the node and the Service-type (Loadbalancer/Ingress etc.).

Apply manifests

kubectl apply -f <name of manifests>

Initial configuration

Open the URL e.g. k8s-lb-ip:8080 and follow the instructions.
You can find the initial password in the pod logs.

Use Jenkins

You define your Pipeline in a File called Jenkinsfile.
A very basic one (doesn't actually do anything xd) would look like this:

pipeline {
    agent any
    stages {
        stage('test') {
            steps {
                sh 'echo "Im testing this."'
            }
        }
        stage('build') {
            steps {
                sh 'echo "Im building..."'
            }
        }
        stage('deploy') {
            steps {
                sh 'echo "Deploying..."'
            }
        }
    }
}

To do the specified steps in the actual Jenkinsfile you have to install the required Plugins on the Jenkins-Server.
Also you have to specify credentials e.g. by using the Jenkins Credentials Plugin.
Dashboard > Manage Jenkins > Credentials > System > Global Credentials
Here you can add e.g. the Kubeconfig as secret text or username and passwords to use withCredentials in your pipeline.

withCredentials([usernamePassword(credentialsId: '27d39497-23a4-46cc-8f08-15c07f078563', usernameVariable: 'USERNAME', passwordVariable: 'PASSWORD')]) {
            sh 'docker login -u $USERNAME -p $PASSWORD'  // use CR-login data from credentials
            // sh 'docker login -u $USERNAME -p $PASSWORD ghcr.io'  // Container-Registry-Anmeldedaten aus dem Credential verwenden
            sh 'docker push xamma/my-jenkins-docker:latest'  // push docker image to registry
        }

Create the pipeline on the Jenkins server

Create a new multibranch pipeline and select the Repository URL as well as the Jenkinsfile location.
Take care of the notation of the manifests. I prefixed them to ensure they are created in the right order.

YOU NEED TO INSTALL THE KUBERNETES PLUGIN AND SET UP A NEW CLOUD TO USE IT!!!!
Manage Jenkins > install plugins > kubernetes, git, pipeline etc
Manage Jenkins > Manage nodes > Configure Clouds > Kubernetes
Also configure the Jenkins URL and Jenkins tunnel to where the Jenkins Server runs and where the ClusterIP JLNP service runs.

Kubernetes removed Docker so you cant mount docker.sock anymore. Use Kaniko for building and pushing images..

kubectl create secret docker-registry dockercred --docker-server=https://index.docker.io/v1/ --docker-username
=SECRET --docker-password=SECRET --docker-email=SECRET -n devops-tools

xamma / jenkins-setup