在GKE上创建一个WordPress环境【vol.2：尝试在ConfigMap中编写环境变量！】

2 年 ago

宇, 华

3 minutes

您好，
我是Class Act基礎架構部門的大塚。
上次，我們在GKE上構建了一個簡單的WordPress環境。
由於未使用PV/PVC、ConfigMap、Secrets等，這個配置絕對不適合生產環境，但對於剛開始接觸Kubernetes並進行學習的人來說，這是一個相當不錯的環境。

这次的配置与之前一样，但是我想要停止直接在yaml文件中写入环境变量，并将其转移到ConfigMap中。

建立环境

预先准备的文件清单

★在上一次之后没有差异的文件不作列举。

wordpress-configmap.yaml 的中文释义为「WordPress配置映射文件」。

在Kubernetes中，将wordpress-configmap.yaml传递给系统时，ConfigMap的名称将以metadata.name中指定的名字生成，本例中为”wp-cm”。

apiVersion: v1
kind: ConfigMap
metadata:
  name: wp-cm
data:
  WORDPRESS_DB_HOST: mysql-clusterip
  WORDPRESS_DB_USER : devuser
  WORDPRESS_DB_PASSWORD : password
  WORDPRESS_DB_NAME : gke-wordpress-database

mysql-配置映射.yaml

apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql-cm
data:
  MYSQL_USER : devuser
  MYSQL_PASSWORD : password
  MYSQL_ROOT_PASSWORD : password
  MYSQL_DATABASE : gke-wordpress-database

华语版本：

wordpress-pod.yaml 的同义表达

“wp-cm”在spec.containers.envFrom.configMapRef.name中指的是通过wordpress-configmap.yaml部署的ConfigMap。

apiVersion: v1 
kind: Pod 
metadata: 
  name: wordpress-pod 
  labels: 
    app: wordpress  
spec: 
  containers: 
    - name:  wordpress-con 
      image: wordpress:php8.1-apache 
      ports: 
      - containerPort: 80 
      envFrom:
      - configMapRef:
          name: wp-cm

mysql-pod.yaml文件

apiVersion: v1 
kind: Pod 
metadata: 
  name: mysql-pod  
  labels: 
    app: mysql  
spec: 
  containers: 
    - name:  mysql-con  
      image: mysql:8.0-debian 
      ports:  
      - containerPort: 3306  
      envFrom:
      - configMapRef:
          name: mysql-cm

建立

我们将从ConfigMap部署。

$ kubectl apply -f wordpress-configmap.yaml 
configmap/wp-cm created
$ kubectl apply -f mysql-configmap.yaml 
configmap/mysql-cm created

在Kubernetes上，可以像获取pod等资源一样，使用kubectl get或describe命令获取ConfigMap。

$ kubectl get cm -o wide 
NAME               DATA   AGE
kube-root-ca.crt   1      11m
mysql-cm           4      46s
wp-cm              4      75s

$ kubectl describe cm wp-cm
Name:         wp-cm
Namespace:    default
Labels:       <none>
Annotations:  <none>

Data
====
WORDPRESS_DB_HOST:
----
mysql-clusterip
WORDPRESS_DB_NAME:
----
gke-wordpress-database
WORDPRESS_DB_PASSWORD:
----
password
WORDPRESS_DB_USER:
----
devuser

BinaryData
====

Events:  <none>

$ kubectl describe cm mysql-cm
Name:         mysql-cm
Namespace:    default
Labels:       <none>
Annotations:  <none>

Data
====
MYSQL_DATABASE:
----
gke-wordpress-database 
MYSQL_PASSWORD:
----
password
MYSQL_ROOT_PASSWORD:
----
password
MYSQL_USER:
----
devuser

BinaryData
====

Events:  <none>

逐步部署Pod、Service等组件

$ kubectl apply -f wordpress-pod.yaml 
Warning: Autopilot set default resource requests for Pod default/wordpress-pod, as resource requests were not specified. See http://g.co/gke/autopilot-defaults
pod/wordpress-pod created
$ kubectl apply -f mysql-pod.yaml 
Warning: Autopilot set default resource requests for Pod default/mysql-pod, as resource requests were not specified. See http://g.co/gke/autopilot-defaults
pod/mysql-pod created
$ kubectl apply -f mysql-clusterip.yaml 
service/mysql-clusterip created
$ kubectl apply -f wordpress-loadbalancer.yaml 
service/wordpress-loadbalancer created

NAME                READY   STATUS    RESTARTS   AGE     IP             NODE                          NOMINATED NODE   READINESS GATES
pod/mysql-pod       1/1     Running   0          2m37s   10.112.0.130   gk3-my-pool-1-51c2fff1-cf9x   <none>           <none>
pod/wordpress-pod   1/1     Running   0          3m4s    10.112.0.131   gk3-my-pool-1-51c2fff1-cf9x   <none>           <none>

NAME                             TYPE           CLUSTER-IP       EXTERNAL-IP     PORT(S)           AGE     SELECTOR
service/kubernetes               ClusterIP      10.112.128.1     <none>          443/TCP           16m     <none>
service/mysql-clusterip          ClusterIP      10.112.128.189   <none>          3306/TCP          2m15s   app=mysql
service/wordpress-loadbalancer   LoadBalancer   10.112.129.17    34.72.240.175   60000:31724/TCP   2m1s    app=wordpress

我也确认了可以在Web浏览器中访问和操作。

另一种导入 ConfigMap 的方法

对于 wordpress-pod.yaml 和 mysql-pod.yaml，不仅限于上述方法，以下的写法也可以接受。
上述方法是将整个 ConfigMap 导入的方式。以下的写法是逐个导入 ConfigMap 的每个环境变量。如果 ConfigMap 中存在不需要的环境变量，或者需要从多个 ConfigMap 导入环境变量的情况下，我认为应该使用这种方法。

apiVersion: v1 
kind: Pod 
metadata: 
  name: wordpress-pod 
  labels: 
    app: wordpress  
spec: 
  containers: 
    - name:  wordpress-con 
      image: wordpress:php8.1-apache 
      ports: 
      - containerPort: 80 
      env:
        - name: WORDPRESS_DB_HOST
          valueFrom:
            configMapKeyRef:
              name: wp-cm
              key: WORDPRESS_DB_HOST
        - name: WORDPRESS_DB_USER
          valueFrom:
            configMapKeyRef:
              name: wp-cm
              key: WORDPRESS_DB_USER
        - name: WORDPRESS_DB_PASSWORD
          valueFrom:
            configMapKeyRef:
              name: wp-cm
              key: WORDPRESS_DB_PASSWORD
        - name: WORDPRESS_DB_NAME
          valueFrom:
            configMapKeyRef:
              name: wp-cm
              key: WORDPRESS_DB_NAME

apiVersion: v1 
kind: Pod 
metadata: 
  name: mysql-pod  
  labels: 
    app: mysql  
spec: 
  containers: 
    - name:  mysql-con  
      image: mysql:8.0-debian 
      ports:  
      - containerPort: 3306  
      env:
        - name: MYSQL_USER
          valueFrom:
            configMapKeyRef:
              name: mysql-cm
              key: MYSQL_USER
        - name: MYSQL_PASSWORD
          valueFrom:
            configMapKeyRef:
              name: mysql-cm
              key: MYSQL_PASSWORD
        - name: MYSQL_ROOT_PASSWORD
          valueFrom:
            configMapKeyRef:
              name: mysql-cm
              key: MYSQL_ROOT_PASSWORD
        - name: MYSQL_DATABASE
          valueFrom:
            configMapKeyRef:
              name: mysql-cm
              key: MYSQL_DATABASE