Demo Jenkins Plugin Installation

In this guide, you’ll learn how to install multiple Jenkins plugins automatically by leveraging the Jenkins Remote API. This approach avoids manual UI steps under Manage Jenkins → Manage Plugins, speeding up your CI/CD setup.

1. Verify Jenkins Is Running

First, confirm that the Jenkins service is active:

sudo systemctl status jenkins

Example output:

● jenkins.service - LSB: Start Jenkins at boot time
   Loaded: loaded (/etc/init.d/jenkins; generated)
   Active: active (exited) since Tue 2021-06-15 05:07:43 UTC; 1h 39min ago
     Docs: man:systemd-sysv-generator(8)

Next, retrieve the initial admin password for API authentication:

sudo cat /var/lib/jenkins/secrets/initialAdminPassword
# e.g. 14f8cea6ad4b0a883997e96d4a6a7

2. Explore the Plugin Installer Script

Assuming you cloned the devsecops-k8s-demo repository, navigate to the Jenkins plugins directory:

cd devsecops-k8s-demo/setup/jenkins-plugins/
ls -l

2.1 plugins.txt

Here’s how the file lists desired plugins:

2.2 plugin-installer.sh

This Bash script automates plugin installation using the Jenkins Remote API and jq for JSON parsing:

#!/bin/bash
set -e

JENKINS_URL="http://localhost:8080"
ADMIN_USER="admin"
ADMIN_PASSWORD=$(sudo cat /var/lib/jenkins/secrets/initialAdminPassword)

# Fetch CRSF protection crumb
JENKINS_CRUMB=$(
  curl -s --cookie-jar /tmp/cookies \
       -u ${ADMIN_USER}:${ADMIN_PASSWORD} \
       "${JENKINS_URL}/crumbIssuer/api/json" \
  | jq -r .crumb
)

# Generate a new API token for 'admin'
JENKINS_TOKEN=$(
  curl -s -X POST \
       -H "Jenkins-Crumb:${JENKINS_CRUMB}" \
       --cookie /tmp/cookies \
       -u ${ADMIN_USER}:${ADMIN_PASSWORD} \
       "${JENKINS_URL}/me/descriptorByName/jenkins.security.ApiTokenProperty/generateNewToken?newTokenName=plugin-installer" \
  | jq -r .data.tokenValue
)

echo "Jenkins URL: ${JENKINS_URL}"
echo "API Token: ${JENKINS_TOKEN}"

# Install each plugin from plugins.txt
while read -r plugin; do
  echo "Installing ${plugin}..."
  curl -s --user "${ADMIN_USER}:${JENKINS_TOKEN}" \
       -H "Content-Type: text/xml" \
       --data "<jenkins><install plugin='${plugin}' /></jenkins>" \
       "${JENKINS_URL}/pluginManager/installNecessaryPlugins"
done < plugins.txt

echo "Plugin installation requests sent."
echo "Some plugins may require a safe restart:"
echo "  ${JENKINS_URL}/safeRestart"

3. Run the Installer

Execute the installer script:

bash plugin-installer.sh

Sample output:

Jenkins URL: http://localhost:8080
API Token: 8f2a...
Installing [email protected]...
Installing [email protected]...
…
Installing [email protected]...
Plugin installation requests sent.
Some plugins may require a safe restart:
  http://localhost:8080/safeRestart

4. Verify Plugin Installation

1. Open Manage Jenkins → Manage Plugins → Installed in the Jenkins UI.
2. If any plugin is missing, switch to Available, search for it (e.g., “Kubernetes CLI”), select the version, and click Install without restart.

5. Next Steps

With your plugins in place, create a Jenkins pipeline that integrates Maven, Docker, and Kubernetes to validate the new capabilities.

Links and References

• Jenkins Remote API
• jq Manual
• Manage Jenkins Plugins