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Distribute Credentials Securely Using Secrets

This page shows how to securely inject sensitive data, such as passwords and encryption keys, into Pods.

Before you begin

You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using Minikube, or you can use one of these Kubernetes playgrounds:

To check the version, enter kubectl version.

Convert your secret data to a base-64 representation

Suppose you want to have two pieces of secret data: a username my-app and a password 39528$vdg7Jb. First, use Base64 encoding to convert your username and password to a base-64 representation. Here’s a Linux example:

echo -n 'my-app' | base64
echo -n '39528$vdg7Jb' | base64

The output shows that the base-64 representation of your username is bXktYXBw, and the base-64 representation of your password is Mzk1MjgkdmRnN0pi.

Create a Secret

Here is a configuration file you can use to create a Secret that holds your username and password:

pods/inject/secret.yaml
apiVersion: v1
kind: Secret
metadata:
  name: test-secret
data:
  username: bXktYXBw
  password: Mzk1MjgkdmRnN0pi
  1. Create the Secret

    kubectl create -f https://k8s.io/docs/tasks/inject-data-application/secret.yaml
  2. View information about the Secret:

    kubectl get secret test-secret

    Output:

    NAME          TYPE      DATA      AGE
    test-secret   Opaque    2         1m
    
  3. View more detailed information about the Secret:

    kubectl describe secret test-secret

    Output:

    Name:       test-secret
    Namespace:  default
    Labels:     <none>
    Annotations:    <none>
    
    Type:   Opaque
    
    Data
    ====
    password:   13 bytes
    username:   7 bytes
    
Note: If you want to skip the Base64 encoding step, you can create a Secret by using the kubectl create secret command:
kubectl create secret generic test-secret --from-literal=username='my-app' --from-literal=password='39528$vdg7Jb'

Create a Pod that has access to the secret data through a Volume

Here is a configuration file you can use to create a Pod:

pods/inject/secret-pod.yaml
apiVersion: v1
kind: Pod
metadata:
  name: secret-test-pod
spec:
  containers:
    - name: test-container
      image: nginx
      volumeMounts:
          # name must match the volume name below
          - name: secret-volume
            mountPath: /etc/secret-volume
  # The secret data is exposed to Containers in the Pod through a Volume.
  volumes:
    - name: secret-volume
      secret:
        secretName: test-secret
  1. Create the Pod:

    kubectl create -f https://k8s.io/docs/tasks/inject-data-application/secret-pod.yaml
  2. Verify that your Pod is running:

    kubectl get pod secret-test-pod

    Output:

    NAME              READY     STATUS    RESTARTS   AGE
    secret-test-pod   1/1       Running   0          42m
  3. Get a shell into the Container that is running in your Pod:

    kubectl exec -it secret-test-pod -- /bin/bash
  4. The secret data is exposed to the Container through a Volume mounted under /etc/secret-volume. In your shell, go to the directory where the secret data is exposed:

    root@secret-test-pod:/# cd /etc/secret-volume
  5. In your shell, list the files in the /etc/secret-volume directory:

    root@secret-test-pod:/etc/secret-volume# ls

    The output shows two files, one for each piece of secret data:

    password username
  6. In your shell, display the contents of the username and password files:

    root@secret-test-pod:/etc/secret-volume# cat username; echo; cat password; echo

    The output is your username and password:

    my-app
    39528$vdg7Jb

Create a Pod that has access to the secret data through environment variables

Here is a configuration file you can use to create a Pod:

pods/inject/secret-envars-pod.yaml
apiVersion: v1
kind: Pod
metadata:
  name: secret-envars-test-pod
spec:
  containers:
  - name: envars-test-container
    image: nginx
    env:
    - name: SECRET_USERNAME
      valueFrom:
        secretKeyRef:
          name: test-secret
          key: username
    - name: SECRET_PASSWORD
      valueFrom:
        secretKeyRef:
          name: test-secret
          key: password
  1. Create the Pod:

    kubectl create -f https://k8s.io/docs/tasks/inject-data-application/secret-envars-pod.yaml
  2. Verify that your Pod is running:

    kubectl get pod secret-envars-test-pod

    Output:

    NAME                     READY     STATUS    RESTARTS   AGE
    secret-envars-test-pod   1/1       Running   0          4m
  3. Get a shell into the Container that is running in your Pod:

    kubectl exec -it secret-envars-test-pod -- /bin/bash
  4. In your shell, display the environment variables:

    root@secret-envars-test-pod:/# printenv

    The output includes your username and password:

    ...
    SECRET_USERNAME=my-app
    ...
    SECRET_PASSWORD=39528$vdg7Jb

What's next

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