Jenkins Docker | How to quickly install Jenkins using docker

In this session, we will understand Jenkins docker. I will explain how to set up Jenkins on your machine using docker and docker-compose. so let’s get started.

Jenkins dockerhub

In dockerhub, there any many ready-to-use images available for Jenkins. There are official images, images from the verified publisher as well as images from sponsored OOS.

You can choose the image as per your need. The safe option is to choose the image which has high downloads and stars.

Jenkins docker image

The most popular Jenkins image is Jenkins/Jenkins which is available in dockerhub. I’ll recommend using this image as this image is continuously updated by the open-source community and has very less vulnerability as compared to other images.

You can visit the Jenkins/Jenkins image github page to read more about how these images have been created.

You will also get information about volume mounting and other configurations.

Jenkins docker install

Jenkins is a popular CICD tool that many companies use to automate the CICD process. To install the Jenkins via docker make sure that the docker instance is running and working.

You can also follow the below tutorials to get familiar with docker.

what docker pull does

docker base image

what all docker images are available

docker jupyter

docker vs docker-compose

We will use the official docker image Jenkins/Jenkins which is available in dockerhub to deploy the Jenkins instance. You can choose the image tag based on your requirement. For this demo, I will be using the latest tag of the Jenkins image.

Let’s create a local directory to assign the volume to the Jenkins container.

mkdir jenkins_data 

Now type the below command to install the Jenkins image

docker run -p 8080:8080 -p 50000:50000 --restart=on-failure -v jenkins_data:/var/jenkins_home jenkins/jenkins:latest

Jenkins image explanation

• -p flag is used to map port 8080 of the container to local port 8080. The Jenkins instance will be available on this port in your local environment.
• We have also mapped the agent port 50000 to local port 50000.
• -v flag is used to mound the local volume jenkins_data to container volume /var/jenkins_home. It means all the data from the /var/jenkins_home folder will be backed up to the local folder jenkins_data.
• a –a restart=on-failure flag will restart the Jenkins instance in case of any failure.

Now go to https://localhost:8080 to access the Jenkins instance.

Pass the admin password which is displayed in the terminal and click on the continue button.

Now click on install suggested plugin to install the plugin suggested by docker.

Once all the necessary plugins are installed, your Jenkins setup is completed.

Now you can either create an admin user or skip and continue as an admin based on your need. For this demo, I am creating a user as per the below screenshot.

Now click on start using Jenkins

Jenkins dockerfile example

So far we have seen how to install Jenkins via a simple readily available image. But user can write their own dockerfile as per their need. Below is the sample dockerfile which will start a Jenkins and install pipeline and GitHub plugin plugins

FROM jenkins/jenkins:lts-jdk11
RUN jenkins-plugin-cli --plugins pipeline-model-definition github-branch-source:1.9

Users can also create a plugins.txt file and mention all the required pluggins>Below is the sample dockerfile for reference

FROM jenkins/jenkins:lts-jdk11
COPY --chown=jenkins:jenkins plugins.txt /usr/share/jenkins/ref/plugins.txt
RUN jenkins-plugin-cli -f /usr/share/jenkins/ref/plugins.txt

More information can be found here

Jenkins docker-compose

So far we have seen how to install Jenkins using the docker command or using the dockerfile. But a user can also install Jenkins using a docker-compose file.

To deploy a container with docker-compose make sure the docker-compose library is installed in your system.

Now create a folder called jenkins_data

mkdir jenkins_data

and create a docker-compose.yml file and paste the below content.

version: '1.1'
services:
  jenkins:
    image: jenkins/jenkins:latest
    restart: on-failure
    privileged: true
    user: root
    ports:
     - 8080:8080
     - 50000:50000
    container_name: jenkins
  volumes:
    - ~/jenkins_data:/var/jenkins_home
    - /var/run/docker.sock:/var/run/docker.sock

Now run the below command to start the Jenkins container.

docker-compose up -d

Goto localhost:8080 to access the Jenkins URL.

Conclusion

I hope you have liked this tutorial about how to install Jenkins via docker and docker-compose. Please do let me know if you are facing any issues while following along.