作者注：本文仅为笔者学习记录，不具任何参考意义。
k8s configmap 实验。
环境 1 2 3 4 5 # kubectl get node NAME STATUS ROLES AGE VERSION edge-node Ready <none> 15m v1.17.0 edge-node2 Ready <none> 16m v1.17.0 ubuntu Ready master 67d v1.17.0
configmap 技术总结 测试要点：
多方式创建，命令行指定，目录，（多）文件。
使用，传递到pod，多个cm。
更新cm。
简写：kubectl create cm
命令行指定 1 kubectl create configmap my-cm --from-literal=who=latelee --from-literal=how.many=250
从目录创建 1 2 3 4 5 wget https://kubernetes.io/examples/configmap/game.properties -O game.properties wget https://kubernetes.io/examples/configmap/ui.properties -O ui.properties # Create the configmap kubectl create configmap game-config --from-file=. // 注！当前目录使用"."
输出yaml格式：
1 kubectl get configmaps game-config -o yaml
整理后config.yaml：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 apiVersion: v1 kind: ConfigMap metadata: name: game-config 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
可执行：
1 kubectl apply -f config.yaml
使用ConfigMapGenerator创建：
1 2 3 4 5 6 7 8 9 cat <<EOF > ./kustomization.yaml configMapGenerator: - name: game-config-4 files: - game.properties # 这里指定文件 - ui.properties EOF kubectl apply -k . // ! 注意格式，不能指定kustomization.yaml文件
注：这种格式得到的创建cm带有随机数。
从json文件创建 deviceProfile.json 文件：
1 {"deviceInstances":[{"id":"led-light-instance-01","name":"led-light-instance-01","model":"led-light"}],"deviceModels":[{"name":"led-light","properties":[{"name":"power-status","dataType":"string","description":"Indicates whether the led light is ON/OFF","accessMode":"ReadWrite","defaultValue":"OFF"},{"name":"gpio-pin-number","dataType":"int","description":"Indicates whether the GPIO pin to which LED is connected","accessMode":"ReadOnly","defaultValue":18}]}],"protocols":[{"protocol_config":null}]}
创建：
1 kubectl create configmap led-config --from-file=deviceProfile.json
在deployment中使用示例：
1 2 3 4 5 6 7 volumeMounts: - name: config-volume mountPath: /opt/kubeedge/ # 挂载到容器的目录 volumes: - name: config-volume configMap: name: led-config # 这是前面创建的configmap名称
此设置下，容器中存在 /opt/kubeedge/deviceProfile.json 。即挂载同名的json文件。json文件内容无须格式化。
参数传递 指定某几种变量。
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 cat <<EOF > busybox-pod.yaml apiVersion: v1 kind: Pod metadata: name: busybox spec: containers: - name: busybox image: latelee/busybox imagePullPolicy: IfNotPresent command: [ "/bin/sh", "-c", "sleep 3600" ] env: - name: SPECIAL_WHO valueFrom: configMapKeyRef: # The ConfigMap containing the value you want to assign to SPECIAL_LEVEL_KEY name: my-cm # Specify the key associated with the value key: who - name: SPECIAL_NUM valueFrom: configMapKeyRef: name: my-cm key: how.many - name: SPECIAL_HOW valueFrom: configMapKeyRef: name: special-config key: special.how EOF
创建：
1 kubectl apply -f busybox-pod.yaml
验证：
1 2 3 4 5 kubectl exec -it busybox env HOSTNAME=busybox TERM=xterm SPECIAL_WHO=latelee SPECIAL_NUM=250
configmap的全部变量。
1 2 3 4 5 6 7 8 9 10 11 cat <<EOF > configmap-multikeys.yaml apiVersion: v1 kind: ConfigMap metadata: name: special-config1 namespace: default data: SPECIAL_LEVEL: very SPECIAL_TYPE: charm special.how: very EOF
pod配置：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 cat <<EOF > pod-busybox-envFrom.yaml apiVersion: v1 kind: Pod metadata: name: busybox spec: containers: - name: busybox image: latelee/busybox imagePullPolicy: IfNotPresent command: [ "/bin/sh", "-c", "sleep 3600" ] envFrom: - configMapRef: name: special-config1 restartPolicy: Never EOF
创建并测试：
1 2 3 4 5 6 7 # kubectl apply -f configmap-multikeys.yaml # kubectl apply -f pod-busybox-envFrom.yaml # kubectl exec -it busybox env special.how=very SPECIAL_LEVEL=very SPECIAL_TYPE=charm
挂载示例pod-busybox-volume.yaml：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 apiVersion: v1 kind: Pod metadata: name: busybox spec: containers: - name: busybox image: latelee/busybox imagePullPolicy: IfNotPresent command: [ "/bin/sh", "-c", "sleep 3600" ] volumeMounts: - name: config-volume mountPath: /etc/myconfig volumes: - name: config-volume configMap: name: special-config1 nodeSelector: ntype: hello restartPolicy: Never
添加节点的标签
1 2 3 kubectl label nodes edge-node2 ntype=hello kubectl create -f pod-busybox-volume.yaml
查询结果：
1 2 3 4 # kubectl exec -it busybox ls /etc/myconfig SPECIAL_LEVEL SPECIAL_TYPE special.how # kubectl exec -it busybox cat /etc/myconfig/SPECIAL_LEVEL very
结论：将key作为文件存在，value为该文件的值。
单个值传递pod-busybox-volume1.yaml：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 apiVersion: v1 kind: Pod metadata: name: busybox spec: containers: - name: busybox image: latelee/busybox imagePullPolicy: IfNotPresent command: [ "/bin/sh", "-c", "sleep 3600" ] volumeMounts: - name: config-volume mountPath: /etc/myconfig volumes: - name: config-volume configMap: name: special-config1 items: - key: SPECIAL_LEVEL path: keys nodeSelector: ntype: hello restartPolicy: Never
查询结果：
1 2 3 4 # kubectl exec -it busybox ls /etc/myconfig keys # kubectl exec -it busybox cat /etc/myconfig/keys very
结论：与上不同，此处只指定其中某一个或多个变量。
自动更新（热更新） 实时修改configmap的值：
1 # kubectl edit cm special-config1
进入 vim 模式，修改 SPECIAL_LEVEL 的值为 veryveryveryloooooooong。
1 2 3 4 5 apiVersion: v1 data: SPECIAL_LEVEL: veryveryveryloooooooong SPECIAL_TYPE: charm special.how: very
稍等片刻后，查看结果：
1 2 # kubectl exec -it busybox cat /etc/myconfig/keys veryveryveryloooooooong
因为 kubelet 检测需要一定时间，所以需要延后查看。
问题及记录 如果指定的变量字段不正确，会提示：
1 Error: couldn't find key sspecial.how in ConfigMap default/special-config # 此处sspecial.how出错
如果pod使用到configmap，但又没有创建configmap，提示：
1 Error: configmap "special-config1" not found
再创建configmap时，pod会自动启动（即不需要先删除）。
注意，在 KubeEdge 中，如果configmap不存在，并不会明确提示，只会显示 Pending 状态。
参考：https://kubernetes.io/zh/docs/tasks/configure-pod-container/configure-pod-configmap/ 。
