Jenkins setup with docker

Install docker on fedora

  sudo dnf -y install dnf-plugins-core

• add repo

  sudo dnf config-manager \
    --add-repo \
    https://download.docker.com/linux/fedora/docker-ce.repo
  

• install docker

   sudo dnf install docker-ce docker-ce-cli containerd.io
  

• start docker service

   sudo systemctl start docker
  

• verify installation

   docker run hello-world
  

• run following command if getting permission denied for "docker run hello-world"

   sudo chmod 666 /var/run/docker.sock
  

Install docker-compose

• refer this doc https://docs.docker.com/compose/install/

Create a docker container for jenkins with docker running inside jenkins container

• create the Docker file to build jenkins container with docker installed and blue ocean plugin

   FROM jenkins/jenkins:lts-jdk11
  
   USER root
  
  
   RUN apt-get update && apt-get install -y apt-transport-https \
          ca-certificates curl gnupg2 \
          software-properties-common
   RUN curl -fsSL https://download.docker.com/linux/debian/gpg | apt-key add -
   RUN apt-key fingerprint 0EBFCD88
   RUN add-apt-repository \
          "deb [arch=amd64] https://download.docker.com/linux/debian \
          $(lsb_release -cs) stable"
   RUN apt-get update && apt-get install -y docker-ce-cli
  
   RUN groupadd docker
  
   RUN usermod -aG docker jenkins
  
   USER jenkins
  
   RUN jenkins-plugin-cli --plugins "blueocean:1.24.6 docker-workflow:1.26"
  

• docker-compose.yml file to build the dockerized jenkins contianer with docker and blueocean plugin

   version: '3.8'
   networks:
          jenkins-network:
              name: jenkins
   volumes:
          data:
              name: jenkins-data
          certs:
              name: jenkins-docker-certs
   services:  
          dind:
              container_name: jenkins-docker
              image: docker:dind
              privileged: true
              restart: unless-stopped
              networks:
                 jenkins-network:
                        aliases:
                            - docker
              ports:
                 - 3000:3000
              volumes:
                 - data:/var/jenkins_home
                 - certs:/certs/client
              environment:
                 - DOCKER_TLS_CERTDIR=/certs
  
          jenkins:
              container_name: jenkins
              image: jenkins-ansible
              build:
                 context: jenkins-ansible          #this is the path to the directory where I have my Dockerfile stored
              restart: unless-stopped
              networks:
                 - jenkins-network
              ports:
                 - '8080:8080'
                 - '50000:50000'
                 - '3000:3000'
              volumes:
                 - data:/var/jenkins_home
                 - certs:/certs/client:ro
              environment:
                 - DOCKER_HOST=tcp://docker:2376
                 - DOCKER_CERT_PATH=/certs/client
                 - DOCKER_TLS_VERIFY=1
  

• run the "docker-compose build" commmand to build the images and then "docker-compose up -d" to bring up the containers

• execute "docker ps" to get the list of srunning containers

• to verify if the docker is runnnig inside the container , execute "docker exec -it <container_name> bash" to get inside the container shell and execute "docker run hello-world" . If the command is a success then docker daemon is running.

Create CI/CD pipeline for simple NodeJs application

• create a pipeline project , dashboard -> newitem -> <your_peipeline_name> -> select pipeline from the list -> click OK

  

• configure the pipeline as shown below, provide the url of the repository for which you want to automate , also mkae sure you have the Jenkinsfile present in the repository to finish the build with success, otherwise create a new Jenkinsfile and commit to the repository

  

• save the pipeline config and click build now to trigger the pipeline, can also set build triggers using github webhooks and SCM polling which will trigger the pipeline if there's any change detected in the repository . I forked this repo for testing purpose, simple-node-js-react-npm-app

• refer this repo for Jenkinsfile used for simple nodejs and react app , https://github.com/shakyav/simple-node-js-react-npm-app

• Once the pipeline is triggered you can view the output as hown below

  

• You can also view the console output as shown below

  

• Or you can aslo view the pipeline with blueocean plugin as well if installed

  

Create docker container with jenkins and ansible

• create a directory jenkins-ansible inside jenkns-data and create a Dockerfile inside jenkins-ansible

• Dockerfile for jenkins container with ansible installed, need root permissions to install ansible hence we used "USER root" inside docker file and then executed the apt-get update and install ansible command and switched back to USER jenkins

   FROM jenkins/jenkins
  
   USER root
  
   RUN apt-get update && apt-get -y install ansible
  
   USER jenkins
  

• docker-compose file to spin up docker container with jenkins and ansible, volumes section specify that all the data that you have inside jenkins_home directory on your local machine will be reflected in the /var/jenkins_home directory inside the jenkins docker container

   #docker compose file to spin a jenkins container only
  
   version: '3'
   services:
     jenkins:
        container_name: jenkins
        image: jenkins-ansible
        build:
        context: jenkins-ansible
        ports:
        - "8080:8080"     #container port 8080 will be forwarded to the localhost port 8080, localhost_port:container_port
        volumes:
        - $PWD/jenkins_home:/var/jenkins_home
        networks:
        - net
   networks:
     net: 
  

Create docker container with jenkins image

• create a directory jenkins-data where we will store all the jenkins related files

   mkdir jenkins-data
  

• create docker-comapose.yml file to build up jenkins container

   #docker compose file to spin a jenkins container only
  
   version: '3'
   services:
     jenkins:
        container_name: jenkins
        image: jenkins/jenkins
        ports:
        - "8080:8080"
        volumes:
        - $PWD/jenkins_home:/var/jenkins_home
        networks:
        - net
   networks:
     net: 
  

• execute "docker-compose build" to build the container and "docker-compose up -d" to start the container

• verify docker containers running, "docker ps" command lists all the docker containers running

• login to the container shell , "docker exec -it jenkins bash" command will ley you acces the shell inside the container, type "exit" to come out

• access jenkins UI at http://localhost:8080 , setup the jenkins admin as prompted by the jenkins UI

• install suggested plugins

Jenkins integration with Gmail

• install the Mailer Plugin if not already installed, go to Manage Jenkins -> Manage Plugins -> type mailer in search bar under available plugin, if not found then check in installed plugins

• follow these steps to allow gmail to send emails

   1. sing-in to gmail account >> navigate to settings >> privacy and security settings
  
   2. setup two step verification settings (because without two step verification we cannot generate application specific password)
  
   3. after setting up two step verification setting in gmail account navigate back to security and privacy settings
  
   4. click on application specific password >> give the name of the application in the drop down as Jenkins (google by default does not have any specific  application password setting for Jenkins) >> this will generate password note down the password generated
  

• after installing the plugin go to Manage Jenkins -> configure System -> Email Notification , configure as shown in following screen

Create jenkins job to run a shell scripit with parameters

• after login to jenkins go to , dashboard -> new item -> enter the job name -> freestyle project -> click OK to save

  

• now you'll be redirected to the configure screen

  

• execute bash scripts with parameters from jenkins

• create bash script in local machine

• copy the script to docker container , container_name:file location wher you want to copy, sample script.sh file is provided in the repository

   docker cp script.sh jenkins:/tmp/script.sh
  

• add prameters as shown in the following screen, I selected the choice(list) parameter and string parameter

  

• choice(list) parameter

  

• string parameter, can set default value for this

  

• add the shell script in the build step

  

Note: if jenkins user doesn't have permissions to execute scripts then grant required permissions using chmod command

• Save the job and go back to the , dashboard -> your job -> click "Build with Parameters" , if you have no parameters setup this button will simply be "build Now"

• click on the job id -> console output , to view results