DevOps Classroomnotes 24/Sep/2022

Jenkins Contd

Triggering Jenkins Job on every new commit

• In Build Triggers, we have an option to poll scm where jenkins watches your source code repository (git) for the new changes i.e. commit in git.
• While using poll scm we use CRON Syntax to configure how frequently jenkins will poll SCM for changes
• Scenario 1: Build time is less
  • Trigger build ASAP when developer pushes the commit
    
    
  • Now push a change & you will observe an build executor getting assigned and executed.
    
  • This is quite a common configuration for day build in projects where we have build times less than 10-15 minutes.
• Scenario 2: Build time is more (50 minutes)
  • In this case we will configure Day build to run every n minutes or hours, in the above case every hour.
  • Lets configure Poll SCM to poll git for changes every hour
    
• Scenario 3: Build for the release to testing team next day
  • Here we need to build the code, deploy the package created on some servers.
  • Probably run some automated tests.
  • This is reffered as nightly build
  • This is generally configured to run at a particular time on every working day.
  • Lets configure to build at 11:30 PM IST on every weekday
    

Upstream and Downstream Jobs

• We can link/chain multiple jobs by using
  • PostBuild Actions => Build other Project
  • Build Triggers => Build after Job
    
    

Scripted Pipeline With Free Style References

• I Want to build a spring petclinic project
  
• In scripted pipeline, we need to select node and then stage and then step
  
  
• Then lets use Scripted Pipeline Sytnax Generator to generate pipeline
  
  
• Ideally the Generated script should be part of the source code and every change can be tracked as it is part of version control system.
• When you define your steps in pipeline in any file which is part of version control we refer it as pipeline as Code.
• The Scripted Pipeline which we generated in the class

node('OPENJDK-11-MAVEN') {
    stage('vcs') {
        git branch: 'REL_INT_1.0', url: 'https://github.com/GitPracticeRepo/spring-petclinic.git'
    }
    stage("build") {
        sh '/opt/apache-maven-3.8.6/bin/mvn package'
    }
    stage("archive results") {
        junit '**/surefire-reports/*.xml'

    }
}

Exercise:

• Find out the different environment variables