Config map example

## config-map.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: nginx-config
data:
  default.conf: |
    server {
      listen 80;
      listen [::]:80;
      server_name  _;
      location / {
        add_header Content-Type text/plain;
        return 200 "Hello world!";
      }
    }

## deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: nginx
  name: nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80
        volumeMounts:
        - name: nginx-configs
          mountPath: /etc/nginx/conf.d
      volumes:
        - name: nginx-configs
          configMap:
            name: nginx-config