Define jenkins tmp folder as persistence volume in stable/jenkins helm chart

ONLINECAST

3 min read

·

06-10-2024

8

0

Share

Unlocking Jenkins' Potential: Making the tmp Folder Persistent with a Helm Chart

Jenkins, the popular open-source automation server, is a powerful tool for building, testing, and deploying software. However, by default, its tmp folder, where temporary files and build artifacts are stored, is ephemeral, meaning data is lost upon container restarts. This can lead to frustrating situations like:

• Lost build artifacts: If a build process is interrupted or the container restarts, you might lose valuable build artifacts.
• Increased build times: If Jenkins has to re-download dependencies for each build due to a lost tmp folder, it can significantly impact build times.

This article will guide you through making the Jenkins tmp folder persistent using a PersistentVolume in the stable/jenkins Helm chart. By doing this, you can eliminate the problems mentioned above and significantly enhance your Jenkins experience.

Understanding the Problem: Ephemeral vs Persistent Storage

Containers are designed to be ephemeral, meaning they can be easily created, destroyed, and recreated. This approach is excellent for scalability and flexibility but can pose challenges for storing data. The default tmp folder in Jenkins is a prime example.

• Ephemeral: This means that the data in the tmp folder is stored in the container's temporary file system, and it is lost when the container restarts or is deleted.
• Persistent: A persistent volume allows data to be stored outside of the container, ensuring that it is retained even if the container is recreated or deleted.

Implementing Persistence with a Helm Chart

The stable/jenkins Helm chart provides a convenient way to deploy and manage Jenkins. We can leverage its features to configure a persistent volume for the tmp folder.

1. Define the Persistent Volume:

First, we need to define a PersistentVolume in our values.yaml file. Here's a simple example:

persistentVolume:
  storageClass: "local-path"
  accessModes: ["ReadWriteOnce"]
  resources:
    requests:
      storage: 10Gi
  hostPath:
    path: "/path/to/your/jenkins/tmp"

• storageClass: Specifies the type of storage to use.
• accessModes: Defines how the volume can be accessed. "ReadWriteOnce" is suitable for a single Jenkins instance.
• resources: Determines the requested storage size (in this example, 10 GiB).
• hostPath: Specifies the path on the host machine where the volume should be mounted.

2. Configure the Persistent Volume Claim:

Next, we need to create a PersistentVolumeClaim in our values.yaml file to request the defined persistent volume:

persistence:
  enabled: true
  size: 10Gi
  storageClass: "local-path"

• enabled: Toggles persistence for the tmp folder.
• size: The requested size for the persistent volume claim.
• storageClass: The storage class to use for the persistent volume claim.

3. Mount the Persistent Volume:

Finally, we need to mount the persistent volume to the correct location within the Jenkins container. This is achieved by setting the tmpDir parameter in the values.yaml file:

jenkins:
  tmpDir: /var/jenkins_home/tmp

This will mount the persistent volume to the /var/jenkins_home/tmp directory within the Jenkins container, ensuring data persistence.

Best Practices and Additional Considerations

• Storage Class: Choose a suitable storageClass based on your environment and requirements. Consult your Kubernetes documentation for available options.
• Security: Ensure that the persistent volume is mounted securely and has appropriate access permissions.
• Backup and Restore: Even with persistent storage, it's crucial to establish a backup and restore strategy for your Jenkins data.
• Monitoring: Monitor your persistent volume usage to avoid exceeding storage limits.

Conclusion

Making the Jenkins tmp folder persistent with a Helm chart is a simple yet impactful change that can dramatically improve your Jenkins workflow. By leveraging the power of persistent volumes, you can avoid losing build artifacts, reduce build times, and ultimately enhance your overall Jenkins experience.

Remember to consult the official documentation for the stable/jenkins Helm chart and your Kubernetes distribution for detailed instructions and best practices. Happy automating!