Error in setup of Kubernetes Secret for C# application in pod

Question

I'm trying to save the database credentials in Kubernetes secret. This will be picked through yaml file of kubernetes depoloyment.yaml.

This is how i created the secret in kubernetes master node:

kubectl create secret generic moiz-db-credentials \
  --from-literal=DB_HOST=77.68.54.25 \
  --from-literal=DB_USER=sa \
  --from-literal=DB_PASSWORD='123456'

This is how i called them in the Kubernetes Deployment file:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: munib-testing-db
  labels:
    app: munib-testing-db
spec:
  replicas: 1
  selector:
    matchLabels:
      app: munib-testing-db
  template:
    metadata:
      labels:
        app: munib-testing-db
    spec:
      containers:
      - name: munib-testing-db
        image: selteq2/munib-testing-db:27
        ports:
        - containerPort: 80
        env:
          - name: DB_USER
            valueFrom:
              secretKeyRef:
                name: moiz-db-credentials
                key: DB_USER
          - name: DB_PASSWORD
            valueFrom:
              secretKeyRef:
                name: moiz-db-credentials
                key: DB_PASSWORD
          - name: DB_HOST
            valueFrom:
              secretKeyRef:
                name: moiz-db-credentials
                key: DB_HOST
      imagePullSecrets:
      - name: regcred

Now i have a confusion that how should i call them in C# application. this is the default way:

"ConnectionStrings": {
    "DefaultConnection": "Server=77.68.54.25;Database=expertCustomer_live_1;User ID=sa;Password=123456;MultipleActiveResultSets=true;TrustServerCertificate=True",
  }

I have changed them to the environment variable that i created but still i'm getting this error in swagger:

Any suggestion what im doing doing wrong?

Answer 1

The deployment configuration takes the value of the k8s secret oiz-db-credentials at the key DB_PASSWORD, and exposes this value as an environment variable (inside your pod) which has the key DB_PASSWORD.

So if you run kubectl exec -it <your_pod> /bin/sh, and then run env, you'll see your env var DB_PASSWORD with the key being your actual password value (extracted from the secret).

So to get the value of this environment variable in your C# app, you need to do something like:

var password = Environment.GetEnvironmentVariable("DB_PASSWORD");