本页将展示如何为kubernetes Pod下的容器设置环境变量。

Before you begin

You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using Minikube, or you can use one of these Kubernetes playgrounds:

为容器设置一个环境变量

创建Pod时,可以为其下的容器设置环境变量。通过配置文件的env或者envFrom 字段来设置环境变量。

本示例中,将创建一个只包含单个容器的Pod。Pod的配置文件中设置环境变量的名称为DEMO_GREETING, 其值为"Hello from the environment"。下面是Pod的配置文件内容:

envars.yaml
apiVersion: v1
kind: Pod
metadata:
  name: envar-demo
  labels:
    purpose: demonstrate-envars
spec:
  containers:
  - name: envar-demo-container
    image: gcr.io/google-samples/node-hello:1.0
    env:
    - name: DEMO_GREETING
      value: "Hello from the environment"
  1. 基于YAML文件创建一个Pod:

    kubectl create -f https://k8s.io/docs/tasks/inject-data-application/envars.yaml
    
  2. 获取一下当前正在运行的Pods信息:

    kubectl get pods -l purpose=demonstrate-envars
    

    查询结果应为:

     NAME            READY     STATUS    RESTARTS   AGE
     envar-demo      1/1       Running   0          9s
    
  3. 进入该Pod下的容器并打开一个命令终端:

    kubectl exec -it envar-demo -- /bin/bash
    
  4. 在命令终端中通过执行printenv打印出环境变量。

    root@envar-demo:/# printenv
    

    打印结果应为:

     NODE_VERSION=4.4.2
     EXAMPLE_SERVICE_PORT_8080_TCP_ADDR=10.3.245.237
     HOSTNAME=envar-demo
     ...
     DEMO_GREETING=Hello from the environment
    
  5. 通过键入exit退出命令终端。

What’s next