（2022版）一套教程搞定k8s安装到实战Secret

　　视频来源：B站《（2022版）最新、最全、最详细的Kubernetes（K8s）教程，从K8s安装到实战一套搞定》
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　　Secret用来保存敏感信息的，比如密码、令牌或者key、Redis、MySQL密码。
　　Secret介绍地址：kubernetes.io/docs/concep…
　　$ *  特殊字符单引号无需转义
　　ImagePullSecret：Pod拉取私有镜像仓库时使用的账号密码，里面的帐号信息，会传递给kubelet，然后kubelet就可以拉去有密码的仓库里面的镜像。
　　创建一个docker registry的secret[root@k8s-master-lb ~]# kubectl create secret docker-registry docker-secret2 --docker-server=hub.docker.com --docker-username=DOCKER_USER --docker-password=DOCKER_PASSWORD --docker-email=DOCKER_EMAIL secret/docker-secret2 created 复制代码
　　test-env-pod.yamlapiVersion: v1 kind: Pod metadata:   name: dapi-test-pod spec:   nodeName: k8s-node01   imagePullSecrets:     - name: docker-secret2   containers:     - name: test-container       image: busybox:1.28       imagePullPolicy: IfNotPresent       command: [ ＂/bin/sh＂, ＂-c＂, ＂sleep 3600＂ ]       volumeMounts:       - name: config-volume         mountPath: /mnt       envFrom:       - configMapRef:           name: special-config       env:         # Define the environment variable         # - name: SPECIAL_LEVEL_KEY         #   valueFrom:         #     configMapKeyRef:         #       # The ConfigMap containing the value you want to assign to SPECIAL_LEVEL_KEY         #       name: special-config         #       # Specify the key associated with the value         #       key: special.how         - name: test           value: test-value         - name: mysqlHostAddress           value: 10.10.10.10         - name: mysqlPort           value: ＂3306＂ # only string   restartPolicy: Never   volumes:     - name: config-volume       configMap:         name: special-config 复制代码
　　subPath解决目录覆盖的问题apiVersion: v1 kind: Pod metadata:   name: dapi-test-pod spec:   nodeName: k8s-node01   imagePullSecrets:     - name: docker-secret2   containers:     - name: test-container       image: busybox:1.28       imagePullPolicy: IfNotPresent       command: [ ＂/bin/sh＂, ＂-c＂, ＂sleep 3600＂ ]       volumeMounts:       - mountPath: /etc/nginx/nginx.conf         name: config-volume         subPath: etc/nginx/nginx.conf       envFrom:       - configMapRef:           name: special-config       env:         # Define the environment variable         # - name: SPECIAL_LEVEL_KEY         #   valueFrom:         #     configMapKeyRef:         #       # The ConfigMap containing the value you want to assign to SPECIAL_LEVEL_KEY         #       name: special-config         #       # Specify the key associated with the value         #       key: special.how         - name: test           value: test-value         - name: mysqlHostAddress           value: 10.10.10.10         - name: mysqlPort           value: ＂3306＂ # only string   restartPolicy: Never   volumes:     - configMap:         defaultMode: 420         items:         - key: nginx.conf           path: etc/nginx/nginx.conf         name: nginx-conf       name: config-volume 复制代码
　　ConfigMap和Secret如果是以subPath的形式挂载的，那么Pod是不会感知到ConfigMap和Secret的更新的。
　　如果Pod的变量来自于ConfigMap和Secret中定义的内容，那么ConfigMap和Secret更新后，也不会更新Pod中的变量。
　　解决办法apiVersion: v1 kind: Pod metadata:   name: dapi-test-pod spec:   nodeName: k8s-node01   imagePullSecrets:     - name: docker-secret2   containers:     - name: test-container       image: busybox:1.28       imagePullPolicy: IfNotPresent       command: [ ＂/bin/sh＂, ＂-c＂, ＂sleep 3600＂ ]       volumeMounts:       - mountPath: /etc/nginx/nginx.conf         name: config-volume         subPath: etc/nginx/nginx.conf       - mountPath: /mnt/         name: config-volume-non-subpath       envFrom:       - configMapRef:           name: special-config       env:         # Define the environment variable         # - name: SPECIAL_LEVEL_KEY         #   valueFrom:         #     configMapKeyRef:         #       # The ConfigMap containing the value you want to assign to SPECIAL_LEVEL_KEY         #       name: special-config         #       # Specify the key associated with the value         #       key: special.how         - name: test           value: test-value         - name: mysqlHostAddress           value: 10.10.10.10         - name: mysqlPort           value: ＂3306＂ # only string   restartPolicy: Never   volumes:     - configMap:         defaultMode: 420         items:         - key: nginx.conf           path: etc/nginx/nginx.conf         name: nginx-conf       name: config-volume     - configMap:         defaultMode: 420         name: nginx-conf       name: config-volume-non-subpath 复制代码
　　postStart：容器启动之前执行的命令
　　preStop：容器停止之前执行的命令
　　热更新ConfigMap或Secret：kubectl create cm nginx-conf --from-file=nginx.conf --dry-run -oyaml | kubectl replace -f- 复制代码
　　immutable：在ConfigMap和Secret的最后加上如下内容，则不再可以edit该ConfigMap或Secretimmutable: true 复制代码