Jump right into Kubernetes development with career-focused lessons and hands-on practice.

DevOps for Developers

Kubernetes is a powerful container management tool that's taking the world by storm. This detailed course will help you master it.

In this course, you'll start with the fundamentals of Kubernetes and what the main components of a cluster look like. You'll then learn how to use those components to build, test, deploy, and upgrade applications, as well as how to achieve state persistence once your application is deployed. You'll also learn how to secure your deployments and manage resources, which are crucial DevOps skills.

By the time you're done, you'll have a firm grasp on what Kubernetes is, as well as the skills to deploy your own clusters and applications with confidence.

A Practical Guide to Kubernetes

# Looking into the definition
Let’s see how we can mount the Secret we created. For this, let’s see an updated definition of `jenkins.yml`. The definition (limited to the relevant parts) is as follows:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: jenkins
spec:
  ...
  template:
    ...
    spec:
      containers:
      - name: jenkins
        image: vfarcic/jenkins
        env:
        - name: JENKINS_OPTS
          value: --prefix=/jenkins
        volumeMounts:
        - name: jenkins-home
          mountPath: /var/jenkins_home
        - name: jenkins-creds
          mountPath: /etc/secrets
      volumes:
      - name: jenkins-home
        emptyDir: {}
      - name: jenkins-creds
        secret:
          secretName: my-creds
          defaultMode: 0444
          items:
          - key: username
            path: jenkins-user
          - key: password
            path: jenkins-pass
...

* **Lines 19--20:** We add `jenkins-creds` which mounts the `/etc/secrets` directory. 

* **Lines 24--26:** The `jenkins-creds` volume references the Secret named `my-creds`. 

* **Line 27:** Since we want the process inside the container to only read the Secret, we set the `defaultMode` to `0444`. That will give read permissions to everyone. Typically, we’d set it to `0400`, therefore giving the read permissions only to the root user. However, since the Jenkins image uses the `jenkins` user, we give read permissions to everyone instead of only to the `root` user.

* **Lines 29--32:**  Finally, since the image expects files named `jenkins-user` and `jenkins-pass`, we make explicit paths. Otherwise, Kubernetes would create the files `username` and `password`.
# Applying the definition
Let's apply the new definition:

Learn to mount generic Secrets to secure the deployed Jenkins.

Mounting Generic Secrets

Looking into the definition