k8s Pod 环境变量和配置注入

一、创建ConfigMap

apiVersion: v1
kind: ConfigMap
metadata:
  name: dataflow-config
data:
  loglevel: info
  env: test

二、引入指令配置到容器环境变量

apiVersion: v1
kind: Pod
metadata:
  name: test-configmap-pod
  labels:
    name: test-configmap-pod
spec:
  containers:
  - name: test-configmap-pod
    image: busybox
    resources:
      limits:
        memory: "128Mi"
        cpu: "500m"
    command: ['/bin/sh','-c','env']
    ports:
      - containerPort: 80
    env: # 单个环境变量
      - name: loglevel
        valueFrom:
          configMapKeyRef:
            name: dataflow-config
            key: loglevel
      - name: profile
        valueFrom:
          configMapKeyRef:
            name: dataflow-config
            key: env

三、引入所有配置到容器环境变量

apiVersion: v1
kind: Pod
metadata:
  name: test-configmap-pod2
  labels:
    name: test-configmap-pod2
spec:
  containers:
  - name: test-configmap-pod2
    image: busybox
    resources:
      limits:
        memory: "128Mi"
        cpu: "500m"
    command: ['/bin/sh','-c','env']
    ports:
      - containerPort: 80
    envFrom: # 批量引入环境变量
      - configMapRef:
          name: dataflow-config
        prefix: dataflow.
  restartPolicy: Never

四、配置挂载每个配置为一个文件

将会在 /etc/dataflow/loglevel 的文件中记录配置的内容

apiVersion: v1
kind: Pod
metadata:
  name: test-configmap-pod3
  labels:
    name: test-configmap-pod3
spec:
  containers:
  - name: test-configmap-pod3
    image: busybox
    resources:
      limits:
        memory: "128Mi"
        cpu: "500m"
    command: ['/bin/sh','-c','cat /etc/dataflow/loglevel']
    ports:
      - containerPort: 80
    volumeMounts:
      - mountPath: /etc/dataflow
        name: frontend-vol
  restartPolicy: Never
  volumes:
    - name: frontend-vol
      configMap:  # 使用挂载volume方式引入配置
        name: dataflow-config
        items:
          - key: loglevel
            path: loglevel

指定了items将会只创建指定的配置文件，如果不指定items，将会configMap中所有的配置项都分别创建配置文件。

五、将POD信息作为环境变量

apiVersion: v1
kind: Pod
metadata:
  name: test-configmap-pod5
  labels:
    name: test-configmap-pod5
spec:
  containers:
  - name: test-configmap-pod5
    image: busybox
    resources:
      limits:
        memory: "128Mi"
        cpu: "500m"
    command: ['/bin/sh','-c','env']
    env:
      - name: POD_NAME
        valueFrom:
          fieldRef: 
            fieldPath: metadata.name
      - name: POD_IP
        valueFrom:
          fieldRef: 
            fieldPath: status.podIP

supports metadata.name, metadata.namespace, metadata.labels['<KEY>'], metadata.annotations['<KEY>'], spec.nodeName, spec.serviceAccountName, status.hostIP, status.podIP, status.podIPs.

六、将POD资源作为环境变量

apiVersion: v1
kind: Pod
metadata:
  name: test-configmap-pod6
  labels:
    name: test-configmap-pod6
spec:
  containers:
  - name: test-configmap-pod6
    image: busybox
    resources:
      requests:
        memory: "32Mi"
      limits:
        memory: "128Mi"
        cpu: "500m"
    command: ['/bin/sh','-c','env']
    env:
      - name: CPU_LIMIT
        valueFrom:
          resourceFieldRef: 
            resource: limits.cpu
      - name: MEMORY_REQUSETS
        valueFrom:
          resourceFieldRef: 
            resource: requests.memory
      - name: MEMORY_LIMIT
        valueFrom:
          resourceFieldRef: 
            resource: limits.memory
      - name: POD_IP
        valueFrom:
          fieldRef: 
            fieldPath: status.podIP

七、将POD 信息挂载为文件

apiVersion: v1
kind: Pod
metadata:
  name: test-configmap-pod7
  labels:
    name: test-configmap-pod7
    owner: yangyan
spec:
  containers:
  - name: test-configmap-pod7
    image: busybox
    resources:
      requests:
        memory: "32Mi"
      limits:
        memory: "128Mi"
        cpu: "500m"
    command: ['/bin/sh','-c','cat /etc/pod/*']
    volumeMounts:
      - mountPath: /etc/pod
        name: podinfo
        readOnly: false
  volumes:
    - name: podinfo
      downwardAPI:
        items:
          - path: labels
            fieldRef:
              fieldPath: metadata.labels
          - path: annotations
            fieldRef:
              fieldPath: metadata.annotations
  restartPolicy: Never