Jenkins-demo

Jenkins starts on port 8080 by default

Two ways to install and run Jenkins:

• install the Jenkins app on the OS directly
• run Jenkins image and start Jenkins as a docker container

--> Open port 50000 on Jenkins: here Jenkins master and worker nodes communicate --> Jenkins can be built and started as a cluster if you have large workloads that you are running with Jenkins --> Initial Jenkins password is located at: /var/volume_name/secrets/initialadminpassword

• spin up an EC2 instance on AWS

• open port 22 (for ssh) and port 8080(access jenkins externally) in inbound rules for the security group attached

• we will run Jenkins's official image to start Jenkins on the Ubuntu server

• For this, we need the installation of docker on the server

• sudo apt update

• sudo apt install docker.io

• By default, the Docker daemon socket is only accessible to users in the "docker" group. You can add your current user to this group using the following command:

• sudo usermod -aG docker $USER

• docker login

• enter username & password or PAT to login

• Starting Jenkins on the server sudo docker run -d -p 8080:8080 -p 50000:50000 -v jenkins_home:/var/jenkins_home jenkins/jenkins

  

• Access Jenkins UI from the browser

• setup password by giving the initial password stored at the location mentioned in the UI cat /var/volume_name/secrets/initialadminpassword

• when we log in to the Jenkins container --> we are logged in as a Jenkins user instead of a root user as by default Jenkins is started as a Jenkins user (security best practice)

• install the plugins manually or automatically

• setup the first admin user

• Jenkins is up and running

• inspect the Jenkins mount volume location docker volume inspect jenkins_home

• we can manage and configure build tools and package managers from the Tools tab under the manage Jenkins option:

• To log in as a root user to the Jenkins container, use -u flag :

• installing nodejs and NPM in the container, we logged in as root user

• checking the Linux distro container is using

• download node: https://deb.nodesource.com/ curl -fsSL https://deb.nodesource.com/setup_20.x | bash - sudo apt-get install -y nodejs

  apt-get install -y nodejs

• Creating a job:

  • under new item -> create a job or directly from the UI itself

  • freestyle for demo purposes/ small projects, learning Jenkins etc

  • for the Production environment, we will be using pipeline and multipipeline jobs

  • on clicking the build now button, the job gets run

  • we can see the console output on clicking that tab

  • integrate with the GitHub account to start the build process as soon as changes are committed to the repo

  • the build now takes longer than the previous one because of this integration

  • added new branch "jenkins-job", created test.sh script to print npm version

  • build this branch in Jenkins

  • in the shell command give execute permission to Jenkins user to run test.sh

  • run the build

  • to run and build docker artifacts inside jenkins , we need to make docker available inside the jenkins container docker run -d -p 8080:8080 -p 50000:50000 -v jenkins_home:/var/jenkins_home -v /var/run/docker.sock:/var/run/docker.sock -v $(which docker):/usr/bin/docker jenkins/jenkins these two volumes make docker commands available inside the jenkins container

  • now we have docker commands available inside the jenkins container

  • the Jenkins service user doesnt have permission to read, execute docker commands yet now we are able to execute all the docker commands in the jenkins container

• Running a simple test from maven plugin

• we integrate the git repo, give the branch name where the code is pushed recently , run maven test (runs a simple test file ) and maven package (packages if test is successful into a jar file) git repo:

  

  

  build results:

• To make docker available inside the jenkins container, (docker commands available while building jobs), we need to mount the docker runtime directory from the server/local host to the jenkins container as a volume ie(need to mount additional two volumes: docker volume and docker runtime volume (cmds gets executed from here/ docker executable binary location)

  

• Add permission to jenkins user to execute docker commands

  -- not working, getting docker cli not found error

• stop the jenkins container and run docker run -p 8080:8080 -p 50000:50000 -d -v /var/run/docker.sock:/var/run/docker.sock -v jenkins_home:/var/jenkins_home jenkins/jenkins

• login to the jenkins container and install docker docker exec -it — user root <container id> /bin/bash

• installing docker curl https://get.docker.com/ > dockerinstall && chmod 777 dockerinstall && ./dockerinstall

• The above command downloads and executes the Docker rapid installation script from https://get.docker.com/, which further installs Docker within the container.

• adding sufficient permissions to execute docker commands as jenkins service user sudo chmod 666 /var/run/docker.sock

• login as jenkins user and try to run docker run hello-world

ignore

• lets try other way:

• install docker cli inside the jenkins conatiner using below documentation, did

• https://www.jenkins.io/doc/book/installing/docker/

• now after exec in the jenkins container, we are able to use docker cmd now ignore

• adding docker commands in job config now

• add docker hub creds in jenkins

• use the creds to login to docker hub for pushing the image

• add docker commands in job to build and push the image

• pushed successfully

• we see a warning to secure creds, so we now give the password as stdin inplace of cli parameter