INDEX

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2024-01-05 17:00
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Devops Toolkit... Running Jenkins in Kubernetes
https://www.youtube.com/watch?v=2Kc3fUJANAc

Jenkins operator is (maybe still) in early stages - use helm instad
	helm repo add jenkinsci https://charts.jenkins.io
	
	# jenkins-values.yaml
	controller:
	  ingress:
	    enabled: true
	    apiVersion: networking.k8s.io/v1
	    hostName: jenkins.3.67.0.140.nip.io
	  installPlugins:
	  - kubernetes:1.29.4
	  - workflow-aggregator:2.6
	  - git:4.7.1
	  - configuration-as-code:1.51
	  - blueocean:1.24.6
	
	# Install and open jenkins (running in k8)
	helm upgrade --install jenkins jenkinsci/jenkins --namespace jenkins \
	 --create-namespace --values jenkins-values.yaml --wait
	echo http://jenkins.$INGRESS_HOST.nip.io

	# Get password for "admin" account
	kubectl --namespace jenkins get secret jenkins \
	 --output jsonpath="{.data.jenkins-admin-password}" | base64 --decode

Now open "Blue Ocean" and add a github token - follow steps to add pipeline
	# Jenkinsfile
	pipeline {
	  agent {
	    kubernetes {
	      defaultContainer "shell"
	      yamlFile "jenkins-pod.yaml"
	    }
	  }
	  environment {} # define environment variables here
	  stages {
	    stage("Build") {
	      steps {
	        # Build and push images
	      }
	    }
	    stage("Test") {
	      when { changeRequest target: "master" } # Only test master branch
	      steps {
	        # Create namespace
	        # Build and run image
	        # Rollout changes
	        # Run tests on that image
	        # Delete namespace
	      } 
	    }
	    stage("Deploy") {
	      when { branch "master" }
	      steps {
	        # Point production to use new image
	        # Apply new changes
	      }
	    }
	  }
	}

Now define what these actions are and the role doing these actions
	# jenkins-pod.yaml
	apiVersion: v1
	kind: Pod
	spec:
	  serviceAccount: jenkins
	  containers:
	  - name: shell # How to run shell commands
	    image: alpine
	    command:
	    - cat
	    tty: true
	  - name: kaniko
	    image: gcr.io/kaniko-project/executor:debug
	    command:
	    - cat
	    tty: true
	    voluemMounts: # Mount secrets
	    - name: kaniko-secret
	      mountPath: /kaniko/.docker/
	  - name: kustomize
	    image: nekottyo/kustomize-kubeval
	    command:
	    - cat
	    tty: true
	  volumes:
	  - name: kaniko-secret
	    secret:
	      secretName: regcred
	      items:
	      - key: .dockerconfigjson
	        path: config.json
	
	kubectl --namespace jenkins create secret docker-registry regcred \
	 --docker-server ... # username, password, email
	
	# Last thing to do is define roles
	# roles.yaml
	apiVersion: rbac.authorization.k8s.io/v1
	kind: ClusterRole
	metadata:
	  name: jenkins
	rules:
	  - apiGroups:
	      - "*"
	    resources:
	      - "*"
	    verbs:
	      - "*"
	---
	apiVersion: rbac.authorization.k8s.io/v1
	kind: ClusterRoleBinding
	metadata:
	  name: jenkins
	roleRef:
	  apiGroup: rbac.authorization.k8s.io
	  kind: ClusterRole
	  name: jenkins
	subjects:
	  - kind: ServiceAccount
	    name: jenkins
	    namespace: jenkins
	
	kubectl apply --filename roles.yaml

Now apply the webhooks to link these together
	echo "http://jenkins.$INGRESS_HOST.nip.io/github-webhook/ # Get URL
	# Github repo - settings - webhooks - add (with jenkins URL, json, send all)

	# Jenkins should now be tracking changes
	git push --set-upstream origin BRANCH_NAME # Pushes to new branch
	gh pr create --title "New feature" --body "merging with master" # Makes a PR
	# Look into BlueOcean and can see Jenkins has tested and run this
	# Merge PR on github and Jenkins will test and run again
	# If all working fine, should be now deployed to production

Problem is that Jenkins engine does not scale