Jenkins

A containerized version of Jenkins server with offline setup (preloaded with required plugins) with reverse proxy

Installation

Steps to install Apache web server and Docker:

Apache Web Server Installation

sudo apt update
sudo apt upgrade -y
sudo apt install apache2 -y
# to start automatically at boot time
sudo systemctl enable apache2

Verifying Installation

In a new tab open => http://<your-server-ip>

Installing Docker

Refer => https://docs.docker.com/engine/install/ubuntu/#install-from-a-package

curl -k -O -L https://download.docker.com/linux/ubuntu/dists/jammy/pool/stable/amd64/containerd.io_1.7.25-1_amd64.deb \
-O -L https://download.docker.com/linux/ubuntu/dists/jammy/pool/stable/amd64/docker-buildx-plugin_0.19.3-1~ubuntu.22.04~jammy_amd64.deb \
-O -L https://download.docker.com/linux/ubuntu/dists/jammy/pool/stable/amd64/docker-ce_27.5.0-1~ubuntu.22.04~jammy_amd64.deb \
-O -L https://download.docker.com/linux/ubuntu/dists/jammy/pool/stable/amd64/docker-ce-cli_27.5.0-1~ubuntu.22.04~jammy_amd64.deb \
-O -L https://download.docker.com/linux/ubuntu/dists/jammy/pool/stable/amd64/docker-compose-plugin_2.6.0~ubuntu-jammy_amd64.deb \
-O -L https://download.docker.com/linux/ubuntu/dists/jammy/pool/stable/amd64/docker-scan-plugin_0.23.0~ubuntu-jammy_amd64.deb

sudo dpkg -i ./*.deb

# to start automatically at boot time
sudo systemctl enable docker

Note

There is an alternate more intuitive method to install the same but if you are behind a corporate network with strict restrictions, you can try the above method. (Remember to update the above links if outdated)

Verify Installation

sudo docker --version
sudo docker run hello-world

Jenkins Setup

Before running jenkins, setup the ssh keys that will be used to fetch the Jenkins pipeline scripts from the private repo in Github.

• In the location where the docker-compose.yml file is stored run (Must be an easily accessible location and not be too nested like in the home or root dir):

mkdir .ssh
ssh-keygen -t ed25519 -f .ssh/id_ed25519.jenkins -P "" -C "[email protected]"
# Also make sure the ssh config file is present
cat <<EOF >config
Host github github.com ssh.github.com
        HostName ssh.github.com
        User git
        port 443
        IdentityFile ~/.ssh/id_ed25519.jenkins
EOF

• On a system with a less strict network in the base directory after cloning the repo run:

docker compose build jenkins

• Now either push the jenkins image that gets generated to docker hub or save as a tar file and use it on the server running jenkins.

# To save to a tarfile
docker save -o jenkins.tar Jeswin8802/jenkins-with-plugins:latest
# to load the image from tarfile on the server
sudo docker load -i jenkins.tar

Note

Remember to add this key to your github account: Paste the output of cat .ssh/id_ed25519.pub into Github

Refer for more info => https://www.jenkins.io/doc/book/installing/docker/

Self signed certificate not recognized (When running docker compose)

Refer: https://stackoverflow.com/a/76244812

To create backup of named volume and bring up the volume from backup

sudo docker run --rm \
	--mount source=jenkins_jenkins-data,target=/mount_point \
	-v "$(pwd)":/backup \
	busybox \
	tar -czf /backup/jenkins-data-export.tgz /mount_point
sudo docker run --rm \
	--mount source=jenkins_jenkins-data,target=/mount_point \
	-v "$(pwd)":/backup \
	busybox \
	tar -xzf /backup/jenkins-data-export.tgz -C /

Jenkins as a systemd service

• Save the file jenkins.service as /etc/systemd/system/jenkins.service

Important

Remember to change the WorkingDirectory param in jenkins.service to the location where docker-compose.yml is stored

# To load the new service file
sudo systemctl daemon-reload
# To start the service, run the command:
sudo systemctl start jenkins

Jenkins should now be up and running. But before accessing the webpage setup reverse proxy by following the steps below

Configure Apache to Reverse Proxy Jenkins

Enable Apache proxy modules

sudo a2enmod proxy
sudo a2enmod proxy_http
sudo a2enmod headers
# Required for websocket
sudo a2enmod proxy_wstunnel
sudo a2enmod rewrite

sudo systemctl restart apache2

Create a new Apache site configuration to reverse proxy Jenkins

• Copy the file jenkins.conf to /etc/apache2/sites-available/:

Refer => https://www.jenkins.io/doc/book/system-administration/reverse-proxy-configuration-with-jenkins/reverse-proxy-configuration-apache/

Enable the new site configuration

sudo a2ensite jenkins.conf
sudo systemctl reload apache2

The site can now be accessed at http://<your-server-ip>/jenkins

Note

Initial Setup Password

When prompted for the admin password, use the below command (Note: sudo used) to fetch it from the container running jenkins

sudo docker exec -it $(sudo docker ps -a | grep jenkins | grep -oP "^\w+") cat /var/jenkins_home/secrets/initialAdminPassword