16-Manage-Kubernetes-secrets.md

Manage Kubernetes Secrets

• Take me to the Video Tutorial

In this section, we will take a look at Manage Kubernetes Secrets.

Web-Mysql Application

• One way is to move the app properties/envs into a configmap. But the configmap stores data into a plain text format. It is definitely not the right place to store a password.

  apiVersion: v1
  kind: ConfigMap
  metadata:
   name: app-config
  data:
    DB_Host: mysql
    DB_User: root
    DB_Password: paswrd
  

  

• Secrets are used to store sensitive information. They are similar to configmaps but they are stored in an encrypted format or a hashed format.

There are 2 steps involved with secrets

• First, Create a secret

• Second, Inject the secret into a pod.

  

There are 2 ways of creating a secret

• The Imperative way

  $ kubectl create secret generic app-secret --from-literal=DB_Host=mysql --from-literal=DB_User=root --from-literal=DB_Password=paswrd
  $ kubectl create secret generic app-secret --from-file=app_secret.properties
  

  

• The Declarative way

  Generate a hash value of the password and pass it to secret-data.yaml definition value as a value to DB_Password variable.
  $ echo -n "mysql" |base64
  $ echo -n "root" |base64
  $ echo -n "paswrd"|base64
  

  Create a secret definition file and run kubectl create to deploy it

  apiVersion: v1
  kind: Secret
  metadata:
   name: app-secret
  data:
    DB_Host: bX1zcWw=
    DB_User: cm9vdA==
    DB_Password: cGFzd3Jk
  

  $ kubectl create -f secret-data.yaml
  

  

Encode Secrets

View Secrets

• To view secrets

  $ kubectl get secrets
  

• To describe secret

  $ kubectl describe secret
  

• To view the values of the secret

  $ kubectl get secret app-secret -o yaml
  

  

Decode Secrets

• To decode secrets

  $ echo -n "bX1zcWw=" |base64 --decode
  $ echo -n "cm9vdA==" |base64 --decode
  $ echo -n "cGFzd3Jk" |base64 --decode
  

  

Configuring secret with a pod

• To inject a secret to a pod add a new property envFrom followed by secretRef name and then create the pod-definition

  apiVersion: v1
  kind: Secret
  metadata:
   name: app-secret
  data:
    DB_Host: bX1zcWw=
    DB_User: cm9vdA==
    DB_Password: cGFzd3Jk
  

   apiVersion: v1
   kind: Pod
   metadata:
     name: simple-webapp-color
   spec:
    containers:
    - name: simple-webapp-color
      image: simple-webapp-color
      ports:
      - containerPort: 8080
      envFrom:
      - secretRef:
          name: app-secret
  

  $ kubectl create -f pod-definition.yaml
  

  

There are other ways to inject secrets into pods.

• You can inject as Single ENV variable

• You can inject as whole secret as files in a Volume

  

Secrets in pods as volume

• Each attribute in the secret is created as a file with the value of the secret as its content.

  

Additional Notes: A Note on Secrets

K8s Reference Docs

• https://kubernetes.io/docs/concepts/configuration/secret/
• https://kubernetes.io/docs/concepts/configuration/secret/#use-cases
• https://kubernetes.io/docs/tasks/inject-data-application/distribute-credentials-secure/