learning kubernetes by minikube, 9

use configmap to make a flexible deployment

create configmap value

To create a configmap for this literal type kubectl create configmap logger --from-literal=log_level=debug

To see all configmaps, kubectl get configmaps

To read the value in the logger configmap, kubectl get configmap/logger -o yaml

To edit the value, kubectl edit configmap/logger

deploy with hardcode

reader-deployment.yaml

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: logreader
spec:
  replicas: 1
  template:
    metadata:
      labels:
        name: logreader
    spec:
      containers:
      - name: logreader
        image: karthequian/reader:latest
        env:
        - name: log_level
          value: "error"

localhost:~ xunyang$ kubectl create -f reader-deployment.yaml 
deployment.extensions "logreader" created
localhost:~ xunyang$ kubectl get deploy
NAME        DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
logreader   1         1         1            1           9m

deploy with configmap

reader-configmap-deployment.yaml

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: logreader-dynamic
spec:
  replicas: 1
  template:
    metadata:
      labels:
        name: logreader-dynamic
    spec:
      containers:
      - name: logreader
        image: karthequian/reader:latest
        env:
        - name: log_level
          valueFrom:
            configMapKeyRef:
              name: logger #Read from a configmap called log-level
              key: log_level  #Read the key called log_level