Practice On Exoscale

Use a Secret to secure the connection to Postgres

In a secret-db.yaml file, add the specification for a Secret containing the key password with the associated value dbpass.
Modify the db Deployment to reference this Secret key (instead of specifying the password in plain text).
Add the POSTGRES_PASSWORD environment variable in the containers of the worker and result Deployments, ensuring that the value of this variable references the key of the Secret created earlier.
Deploy the application defined in this specification and verify that you have access to both the voting and result interfaces.
Delete the application.

Solution

The password we want to store in the Secret is dbpass.

First, we encode this password in base64:

$ echo "dbpass" | base64
ZGJwYXNzCg==

Next, we create the following file defining a Secret:

apiVersion: v1
kind: Secret
metadata:
  name: db
data:
  password: ZGJwYXNzCg==

We modify the db Deployment specification to reference the contents of the Secret key password instead of using the password in plain text:

deploy-db.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: db
  name: db
spec:
  replicas: 1
  selector:
    matchLabels:
      app: db
  template:
    metadata:
      labels:
        app: db
    spec:
      containers:
        - image: postgres:15.1-alpine3.17
          name: postgres
          env:
            - name: POSTGRES_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: db
                  key: password
          ports:
            - containerPort: 5432
              name: postgres

We modify the worker and result Deployments (the two microservices connecting to db) to add the POSTGRES_PASSWORD environment variable, which retrieves its value from the db Secret.

The new worker Deployment specification:

deploy-worker.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: worker
  name: worker
spec:
  replicas: 1
  selector:
    matchLabels:
      app: worker
  template:
    metadata:
      labels:
        app: worker
    spec:
      containers:
        - image: voting/worker:latest
          name: worker
          env:
          - name: POSTGRES_PASSWORD
            valueFrom:
              secretKeyRef:
                name: db
                key: password

The new result Deployment specification:

deploy-result.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: result
  name: result
spec:
  replicas: 1
  selector:
    matchLabels:
      app: result
  template:
    metadata:
      labels:
        app: result
    spec:
      containers:
        - image: voting/result:latest
          name: result
          env:
            - name: POSTGRES_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: db
                  key: password

We deploy the application with the following command from the manifests directory:

kubectl apply -f .

As before, using the IP address of one of the cluster nodes, we can access the voting and result interfaces via ports 31000 and 31001, respectively.

We delete the application with the following command from the manifests directory:

kubectl delete -f .