ConfigMap
ConfigMap 功能在 Kubernetes1.2 版本中引入，许多应用程序会从配置文件、命令行参数或环境变量中读取配
置信息。ConfigMap API 给我们提供了向容器中注入配置信息的机制，ConfigMap 可以被用来保存单个属性，也
可以用来保存整个配置文件或者 JSON 二进制大对象
ConfigMap创建
可以使用kubectl create configmap从文件、目录或者key-value字符串创建等创建ConfigMap。
使用目录创建 使用文件创建 使用字面值创建
[root@k8s-master dir]# cat game.properties enemies=aliens lives=3 enemies.cheat=true enemies.cheat.level=noGoodRotten secret.code.passphrase=UUDDLRLRBABAS secret.code.allowed=true secret.code.lives=30 [root@k8s-master dir]# cat ui.properties color.good=purple color.bad=yellow allow.textmode=true how.nice.to.look=fairlyNice [root@k8s-master dir]#
root@k8s-master dir]# kubectl create configmap game-config --from-file=../dir/ configmap/game-config created [root@k8s-master dir]# kubectl get cm NAME DATA AGE game-config 2 21s [root@k8s-master dir]# kubectl get cm game-config -o yaml apiVersion: v1 data: game.properties: | enemies=aliens lives=3 enemies.cheat=true enemies.cheat.level=noGoodRotten secret.code.passphrase=UUDDLRLRBABAS secret.code.allowed=true secret.code.lives=30 ui.properties: | color.good=purple color.bad=yellow allow.textmode=true how.nice.to.look=fairlyNice kind: ConfigMap metadata: creationTimestamp: "2019-12-25T13:51:28Z" name: game-config namespace: default resourceVersion: "96998" selfLink: /api/v1/namespaces/default/configmaps/game-config uid: 7fa2195e-08b9-4ab2-927b-21420493e28f
[root@k8s-master dir]# kubectl create configmap game-config2 --from-file=game.properties configmap/game-config2 created [root@k8s-master dir]# kubectl get cm NAME DATA AGE game-config 2 4m11s game-config2 1 28s [root@k8s-master dir]# kubectl create configmap special-config --from-literal=special.how=very --from-literal=special.type=charm configmap/special-config created [root@k8s-master dir]# kubectl get cm NAME DATA AGE game-config 2 9m29s game-config2 1 5m46s special-config 2 3s [root@k8s-master dir]# kubectl describe cm special-config Name: special-config Namespace: default Labels: <none> Annotations: <none> Data ==== special.how: ---- very special.type: ---- charm Events: <none> [root@k8s-master dir]# vim env.yaml [root@k8s-master dir]# kubectl apply -f env.yaml configmap/env-config created [root@k8s-master dir]# kubectl get cm NAME DATA AGE env-config 1 6s game-config 2 14m game-config2 1 11m special-config 2 5m32s
Pod 中使用 ConfigMap
Ⅰ、使用 ConfigMap 来替代环境变量
[root@k8s-master dir]# cat pod.yaml apiVersion: v1 kind: Pod metadata: name: dapi-test-pod spec: containers: - name: test-container image: wangyanglinux/myapp:v1 command: [ "/bin/sh", "-c", "env" ] env: - name: SPECIAL_LEVEL_KEY valueFrom: configMapKeyRef: name: special-config key: special.how - name: SPECIAL_TYPE_KEY valueFrom: configMapKeyRef: name: special-config key: special.type envFrom: - configMapRef: name: env-config restartPolicy: Never [root@k8s-master dir]# ll 总用量 28 -rw-r--r-- 1 root root 376 12月 25 22:48 111.yaml -rw-r--r-- 1 root root 105 12月 25 22:06 env.yaml -rw-r--r-- 1 root root 158 12月 25 21:50 game.properties -rw-r--r-- 1 root root 616 12月 25 23:09 log-config.yaml -rw-r--r-- 1 root root 560 12月 25 22:34 pod1.yaml -rw-r--r-- 1 root root 584 12月 25 22:26 pod.yaml -rw-r--r-- 1 root root 83 12月 25 21:50 ui.properties [root@k8s-master dir]# cat env.yaml apiVersion: v1 kind: ConfigMap metadata: name: env-config namespace: default data: log_level: INFO [root@k8s-master dir]#
结果：
[root@k8s-master dir]# vim pod.yaml [root@k8s-master dir]# kubectl create -f pod.yaml pod/dapi-test-pod created [root@k8s-master dir]# kubectl get pod NAME READY STATUS RESTARTS AGE dapi-test-pod 0/1 Completed 0 3s [root@k8s-master dir]# kubectl logs pod dapi-test-pod Error from server (NotFound): pods "pod" not found [root@k8s-master dir]# kubectl logs dapi-test-pod MYAPP_SVC_PORT_80_TCP_ADDR=10.98.57.156 KUBERNETES_PORT=tcp://10.96.0.1:443 KUBERNETES_SERVICE_PORT=443 MYAPP_SVC_PORT_80_TCP_PORT=80 HOSTNAME=dapi-test-pod SHLVL=1 MYAPP_SVC_PORT_80_TCP_PROTO=tcp HOME=/root SPECIAL_TYPE_KEY=charm MYAPP_SVC_PORT_80_TCP=tcp://10.98.57.156:80 NGINX_VERSION=1.12.2 KUBERNETES_PORT_443_TCP_ADDR=10.96.0.1 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin KUBERNETES_PORT_443_TCP_PORT=443 KUBERNETES_PORT_443_TCP_PROTO=tcp MYAPP_SVC_SERVICE_HOST=10.98.57.156 SPECIAL_LEVEL_KEY=very log_level=INFO KUBERNETES_SERVICE_PORT_HTTPS=443 KUBERNETES_PORT_443_TCP=tcp://10.96.0.1:443 PWD=/ KUBERNETES_SERVICE_HOST=10.96.0.1 MYAPP_SVC_SERVICE_PORT=80 MYAPP_SVC_PORT=tcp://10.98.57.156:80
Ⅱ、用 ConfigMap 设置命令行参数
[root@k8s-master dir]# cat pod1.yaml apiVersion: v1 kind: Pod metadata: name: dapi-test-pod66 spec: containers: - name: test-container image: wangyanglinux/myapp:v1 command: [ "/bin/sh", "-c", "echo $(SPECIAL_LEVEL_KEY) $(SPECIAL_TYPE_KEY)" ] env: - name: SPECIAL_LEVEL_KEY valueFrom: configMapKeyRef: name: special-config key: special.how - name: SPECIAL_TYPE_KEY valueFrom: configMapKeyRef: name: special-config key: special.type restartPolicy: Never [root@k8s-master dir]#
结果：
[root@k8s-master dir]# vim pod1.yaml [root@k8s-master dir]# kubectl create -f pod1.yaml pod/dapi-test-pod66 created [root@k8s-master dir]# kubectl get pod NAME READY STATUS RESTARTS AGE dapi-test-pod 0/1 Completed 0 7m45s dapi-test-pod66 0/1 Completed 0 5s [root@k8s-master dir]# kubectl logs dapi-test-pod66 very charm
Ⅲ、通过数据卷插件使用ConfigMap
[root@k8s-master dir]# cat 111.yaml apiVersion: v1 kind: Pod metadata: name: dapi-test-pod11 spec: containers: - name: test-container image: wangyanglinux/myapp:v1 command: [ "/bin/sh", "-c", "sleep 600s" ] volumeMounts: - name: config-volume mountPath: /etc/config volumes: - name: config-volume configMap: name: special-config restartPolicy: Never [root@k8s-master dir]#
结果：
[root@k8s-master dir]# vim 111.yaml [root@k8s-master dir]# kubectl create -f 111.yaml pod/dapi-test-pod11 created [root@k8s-master dir]# kubectl get pod NAME READY STATUS RESTARTS AGE dapi-test-pod 0/1 Completed 0 22m dapi-test-pod11 1/1 Running 0 5s dapi-test-pod66 0/1 Completed 0 14m [root@k8s-master dir]# kubectl exec dapi-test-pod11 -it -- /bin/sh / # cd /etc/config /etc/config # ls special.how special.type /etc/config # cat special.how very/etc/config # cat special.type charm/etc/config # exit
ConfigMap 的热更新
[root@k8s-master dir]# cat log-config.yaml apiVersion: v1 kind: ConfigMap metadata: name: log-config namespace: default data: log_level: INFO --- apiVersion: apps/v1 kind: Deployment metadata: name: my-nginx spec: replicas: 1 selector: matchLabels: app: my-nginx template: metadata: labels: app: my-nginx spec: containers: - name: my-nginx image: wangyanglinux/myapp:v1 ports: - containerPort: 80 volumeMounts: - name: config-volume mountPath: /etc/config volumes: - name: config-volume configMap: name: log-config [root@k8s-master dir]#
结果：
[root@k8s-master dir]# vim log-config.yaml [root@k8s-master dir]# kubectl apply -f log-config.yaml configmap/log-config unchanged deployment.apps/my-nginx created [root@k8s-master dir]# kubectl get pod NAME READY STATUS RESTARTS AGE my-nginx-5d57c6897b-fm2ql 1/1 Running 0 8s [root@k8s-master dir]# kubectl exec my-nginx-5d57c6897b-fm2ql -it -- cat /tec/config/log_level cat: can't open '/tec/config/log_level': No such file or directory command terminated with exit code 1 [root@k8s-master dir]# kubectl exec my-nginx-5d57c6897b-fm2ql -it -- cat /etc/config/log_level INFO[root@k8s-master dir]# kubectl edit configmap log-config configmap/log-config edited [root@k8s-master dir]# kubectl exec my-nginx-5d57c6897b-fm2ql -it -- cat /etc/config/log_level INFO[root@k8s-master dir]# kubectl exec my-nginx-5d57c6897b-fm2ql -it -- cat /etc/config/log_level [root@k8s-master dir]# kubectl exec my-nginx-5d57c6897b-fm2ql -it -- cat /etc/config/log_level DEBUG[root@k8s-master dir]#
更新 ConfigMap 后：
使用该 ConfigMap 挂载的 Env 不会同步更新
使用该 ConfigMap 挂载的 Volume 中的数据需要一段时间（实测大概10秒）才能同步更新