Jenkins scripted pipeline or declarative pipeline

Question

I\'m trying to convert my old style project base workflow to a pipeline based on Jenkins. While going through docs I found there are two different syntaxes named scrip

Answer 1

I made the switch to declarative recently from scripted with the kubernetes agent. Up until July '18 declarative pipelines didn't have the full ability to specify kubernetes pods. However with the addition of the yamlFile step you can now read your pod template from a yaml file in your repo.

This then lets you use e.g. vscode's great kubernetes plugin to validate your pod template, then read it into your Jenkinsfile and use the containers in steps as you please.

pipeline {
  agent {
    kubernetes {
      label 'jenkins-pod'
      yamlFile 'jenkinsPodTemplate.yml'
    }
  }
  stages {
    stage('Checkout code and parse Jenkinsfile.json') {
      steps {
        container('jnlp'){
          script{
            inputFile = readFile('Jenkinsfile.json')
            config = new groovy.json.JsonSlurperClassic().parseText(inputFile)
            containerTag = env.BRANCH_NAME + '-' + env.GIT_COMMIT.substring(0, 7)
            println "pipeline config ==> ${config}"
          } // script
        } // container('jnlp')
      } // steps
    } // stage

As mentioned above you can add script blocks. Example pod template with custom jnlp and docker.

apiVersion: v1
kind: Pod
metadata:
  name: jenkins-pod
spec:
  containers:
  - name: jnlp
    image: jenkins/jnlp-slave:3.23-1
    imagePullPolicy: IfNotPresent
    tty: true
  - name: rsync
    image: mrsixw/concourse-rsync-resource
    imagePullPolicy: IfNotPresent
    tty: true
    volumeMounts:
      - name: nfs
        mountPath: /dags
  - name: docker
    image: docker:17.03
    imagePullPolicy: IfNotPresent
    command:
    - cat
    tty: true
    volumeMounts:
      - name: docker
        mountPath: /var/run/docker.sock
  volumes:
  - name: docker
    hostPath:
      path: /var/run/docker.sock
  - name: nfs
    nfs:
      server: 10.154.0.3
      path: /airflow/dags