tal2k4xj/configmap-workshop

Configmap with volume

$ nano configmap.yaml

apiVersion: v1
kind: ConfigMap
metadata:
  name: tal-cm
data:
  index.html: Tal

$ nano podcm.yaml

apiVersion: v1
kind: Pod
metadata:
  name: configmap-test
  labels:
    app: configmap-test
spec:
  containers:
    - name: test-container
      image: nginx
      ports:
        - name: http-server
          containerPort: 80
      volumeMounts:
      - name: config-volume
        mountPath: /usr/share/nginx/html
  volumes:
    - name: config-volume
      configMap:
        name: tal-cm

$ nano servicecm.yaml

apiVersion: v1
kind: Service
metadata:
  name: configmap-test
  labels:
    app: configmap-test
spec:
  ports:
  - port: 80
    targetPort: http-server
  selector:
    app: configmap-test
  type: NodePort

$ kubectl create -f configmap.yaml

$ kubectl create -f podcm.yaml

$ kubectl create -f servicecm.yaml

$ kubectl get svc

Configmap with env var

1. create configmap

$ kubectl create configmap logger --from-literal=log_level=error

2. see configmap yaml

$ kubectl get configmaps logger -o yaml

3. create reader-cm-deployment.yaml file

$ nano reader-cm-deployment.yaml

4. Copy & Paste yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: log-reader-configmap
spec:
  replicas: 1
  selector:
    matchLabels:
      name: logreader
  template:
    metadata:
      labels:
        name: logreader
    spec:
      containers:
      - name: logreader
        image: karthequian/reader:latest
        env:
        - name: log_level
          valueFrom:
            configMapKeyRef:
              #Read from a configmap called log-level
              name: logger
              #Read the key called log_level
              key: log_level

5. create deploy yaml

$ kubectl apply -f reader-cm-deployment.yaml

6. get configmap reader log

$ kubectl get pods | grep -i log-reader-configmap

log-reader-configmap-678cbc5868-r4sfj   1/1     Running   0          2m

7. View logd of configmap reader pod

$ kubectl logs log-reader-configmap-<random>

8. get inside the pod and see ENV

$ kubectl exec -it log-reader-configmap-<random> /bin/sh