Kubernetes is a powerful tool. It can help you manage complex applications and provide you with the ability to easily automate tasks involved in managing them. In this course, we will start exploring Kubernetes from a beginner's standpoint. We will discuss what Kubernetes is and what it does, and we will work with some of the basic functionality of Kubernetes hands-on. We will build a simple Kubernetes cluster. We will also deploy a sample microservice application to the cluster in order to explore how Kubernetes can help easily manage such applications.

A Practical Guide to Kubernetes

## Looking into the Definition
Let's see how we could mount the Secret we created.

The **output**, limited to the relevant parts, is as follows.

apiVersion: apps/v1beta2
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
...

**Line 19-20:** We added `jenkins-creds` that mounts the `/etc/secrets` directory. 

**Line 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`, thus giving the read permissions only to the `root` user. However, since the Jenkins image uses the `jenkins` user, we gave read permissions to everyone instead of only to the `root` user.

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

# Looking into the Definition
Let's see how we could mount the Secret we created.

**Line 19-20:** We added `jenkins-creds` that mounts the `/etc/secrets` directory. 

**Line 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`, thus giving the read permissions only to the `root` user. However, since the Jenkins image uses the `jenkins` user, we gave read permissions to everyone instead of only to the `root` user.

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

In this lesson, we will mount the generic Secret to secure the deployed Jenkins.

Mounting Generic Secrets

Looking into the Definition