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如何使用configmap
1.环境变量方式注入到pod

创建一个包含两个环境变量的configmap：

kubectl create configmap nginx-config --from-literal=nginx_port=80 --from-literal=server_name=myapp.magedu.com

使用configmap

[root@k8s-master configmap]# vim pod-configmap.yaml
apiVersion: v1
kind: Pod
metadata:
  name: pod-cm-1
  namespace: default
  labels: 
    app: myapp
    tier: frontend
  annotations:
    magedu.com/created-by: "cluster admin"
spec:
  containers:
  - name: myapp
    image: ikubernetes/myapp:v1
    ports:
    - name: http
      containerPort: 80 
    env:
    - name: NGINX_SERVER_PORT
      valueFrom:
        configMapKeyRef:
          name: nginx-config
          key: nginx_port
    - name: NGINX_SERVER_NAME
      valueFrom:
        configMapKeyRef:
          name: nginx-config
          key: server_name

[root@k8s-master configmap]# kubectl apply -f pod-configmap.yaml 
pod/pod-cm-1 created
[root@k8s-master configmap]# kubectl exec -it pod-cm-1 -- /bin/sh
/ # echo $NGINX_SERVER_PORT
80
/ # echo $NGINX_SERVER_NAME
myapp.magedu.com

修改端口，可以发现使用环境变化注入pod中的端口不会根据配置的更改而变化

[root@k8s-master volumes]#  kubectl edit cm nginx-config
configmap/nginx-config edited
/ # echo $NGINX_SERVER_PORT
80

所以说通过configmap注入的环境变量，容器启动后，变量不会随着configmap的修改而改变，此时需要更新容器里面的， 可能就需要重新运行容器，重新加载configmap了

2. 存储卷方式挂载configmap：
   Volume 形式的 ConfigMap 也支持动态更新

[root@k8s-master configmap ~]# vim pod-configmap-2.yaml
apiVersion: v1
kind: Pod
metadata:
name: pod-cm-2
namespace: default
labels:
app: myapp
tier: frontend
annotations:
magedu.com/created-by: “cluster admin”
spec:
containers:

• name: myapp
  image: ikubernetes/myapp:v1
  ports:
  • name: http
    containerPort: 80
    volumeMounts:
  • name: nginxconf
    mountPath: /etc/nginx/config.d/
    readOnly: true
    volumes:
• name: nginxconf
  configMap:
  name: nginx-config
  [root@k8s-master configmap ~]# kubectl apply -f pod-configmap-2.yaml
  pod/pod-cm-2 created
  [root@k8s-master configmap ~]# kubectl get pods
  [root@k8s-master configmap ~]# kubectl exec -it pod-cm-2 – /bin/sh
  / # cd /etc/nginx/config.d
  / # cat nginx_port
  80
  / # cat server_name
  myapp.magedu.com

[root@k8s-master configmap ~]# kubectl edit cm nginx-config #修改端口，再在容器中查看端口是否变化。
apiVersion: v1
data:
nginx_port: “800”
…

/ # cat nginx_port
800
[root@k8s-master configmap ~]# kubectl delete -f pod-configmap2.yaml