第17关 深入理解K8s配置管理：ConfigMap和Secret的终极指南

博哥爱运维2023-12-03 18:14

------> 课程视频同步分享在今日头条和B站

大家好，我是博哥爱运维，K8s是如何来进行服务配置管理的呢？

对于容器而言，如果我们想修改一个容器镜像里面的配置，可以在Dockerfile这一步，将修改好的配置复制到镜像里面再重新打包，对于不用变动配置的镜像而言，这样做属于硬编码当然也可以，但一旦我们的镜像服务需要修改配置，那么就需要重新重新打包非常麻烦，对于K8s而言，对于配置这么重要的一个环节，自然有它的解决方案，那就是configmap（通常普通配置使用）和secret（对于一些机密配置信息使用），在上面的部分章节里面，有提前涉及到这部分内容，但没有进行仔细的讲解，这里就对它们作下详细的实践。

我这里会准备一个deployment的yaml配置，用busybox来作为服务镜像，通过一个完整的yaml就可以快速带大家理解并能熟练在K8s上使用configmap和secret，如果一下子理解不了，后面可以保存这份yaml来作来生产配置参考也是没问题的，用多了自然就熟了，yaml配置如下：

configmap-secret-example-simple.yaml
yaml 复制代码 
---
# configmap
# kubectl create configmap localconfig-env --from-literal=log_level_test=TEST --from-literal=log_level_produce=PRODUCE
apiVersion: v1
kind: ConfigMap
metadata:
  name: localconfig-env
data:
  log_level_test: TEST
  log_level_produce: PRODUCE

---
# configmap
# kubectl create configmap localconfig-file --from-file=localconfig-test=localconfig-test.conf --from-file=localconfig-produce=localconfig-produce.conf
apiVersion: v1
kind: ConfigMap
metadata:
  name: localconfig-file
data:
  localconfig-produce: |
    TEST_RELEASE = False
    PORT = 80
    PROCESSES = 0
    MESSAGE = Produce
  localconfig-test: |
    TEST_RELEASE = True
    PORT = 8080
    PROCESSES = 1
    MESSAGE = Test

---
# secret
# kubectl create secret generic mysecret --from-literal=mysql-root-password='BogeMysqlPassword' --from-literal=redis-root-password='BogeRedisPassword' --from-file=my_id_rsa=/root/.ssh/id_rsa --from-file=my_id_rsa_pub=/root/.ssh/id_rsa.pub
apiVersion: v1
kind: Secret
metadata:
  name: mysecret
  namespace: default
type: Opaque
data:
  my_id_rsa: bXlfaWRfcnNhCg==
  my_id_rsa_pub: bXlfaWRfcnNhX3B1Ygo=
  mysql-root-password: Qm9nZU15c3FsUGFzc3dvcmQ=
  redis-root-password: Qm9nZVJlZGlzUGFzc3dvcmQ=

---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    run: test-busybox
  name: test-busybox
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      run: test-busybox
  template:
    metadata:
      labels:
        run: test-busybox
    spec:
      containers:
      - name: test-busybox
        image: registry.cn-shanghai.aliyuncs.com/acs/busybox:v1.29.2

        args:
          - /bin/sh
          - -c
          - >
              echo "-------------------------------------------------";
              echo "TEST_ENV is:$(TEST_ENV)";
              echo "-------------------------------------------------";
              echo "PRODUCE_ENV is:$(PRODUCE_ENV)";
              echo "-------------------------------------------------";
              echo "secret MYSQL_ROOT_PASSWORD is:$(MYSQL_ROOT_PASSWORD)";
              echo "-------------------------------------------------";
              echo "secret REDIS_ROOT_PASSWORD is:$(REDIS_ROOT_PASSWORD)";
              echo "-------------------------------------------------";
              echo "/etc/local_config_test.py body is:";
              cat /etc/local_config_test.py;
              echo "-------------------------------------------------";
              echo "/etc/local_config_produce.py body is:";
              cat /etc/local_config_produce.py;
              echo "-------------------------------------------------";
              echo "/etc/id_rsa body is:";
              cat /etc/id_rsa;
              echo "-------------------------------------------------";
              echo "/etc/id_rsa.pub body is:";
              cat /etc/id_rsa.pub;
              echo "-------------------------------------------------";
              ls -ltr /etc;
              sleep 30000;
        env:
          - name: TEST_ENV
            valueFrom:
              configMapKeyRef:
                name: localconfig-env
                key: log_level_test
          - name: PRODUCE_ENV
            valueFrom:
              configMapKeyRef:
                name: localconfig-env
                key: log_level_produce
          - name: MYSQL_ROOT_PASSWORD
            valueFrom:
              secretKeyRef:
                name: mysecret
                key: mysql-root-password
          - name: REDIS_ROOT_PASSWORD
            valueFrom:
              secretKeyRef:
                name: mysecret
                key: redis-root-password
        volumeMounts:
        - name: testconfig
          mountPath: "/etc/local_config_test.py"
          subPath: localconfig-test
        - name: testconfig
          mountPath: "/etc/local_config_produce.py"
          subPath: localconfig-produce
          readOnly: true
        - name: testsecret
          mountPath: "/etc/id_rsa"
          subPath: my_id_rsa
          readOnly: true
        - name: testsecret
          mountPath: "/etc/id_rsa.pub"
          subPath: my_id_rsa_pub
          readOnly: true

      volumes:
      - name: testconfig
        configMap:
          name: localconfig-file
          defaultMode: 0660
      - name: testsecret
        secret:
          secretName: mysecret
          defaultMode: 0600
配置自动更新器 reloader

https://github.com/stakater/Reloader

what is reloader

A Kubernetes controller to watch changes in ConfigMap and Secrets and then restart pods for Deployment, StatefulSet and DaemonSet

How to use Reloader

## kind: Deployment
## metadata:
##   annotations:
##     #------ all(ConfigMap and/or Secret)
##     reloader.stakater.com/auto: "true"
##     #------ only configmap for name: "foo-configmap"
##     configmap.reloader.stakater.com/reload: "foo-configmap"
##     #------ many configmaps
##     configmap.reloader.stakater.com/reload: "foo-configmap,bar-configmap,baz-configmap"
##     #------ only secret for name: "foo-secret"
##     secret.reloader.stakater.com/reload: "foo-secret"
##     #------ many secrets
##     secret.reloader.stakater.com/reload: "foo-secret,bar-secret,baz-secret"
## spec:
##   template:
##     metadata:

部署yaml配置

yaml 复制代码 
---
# Source: reloader/templates/serviceaccount.yaml
apiVersion: v1
kind: ServiceAccount
metadata:
  annotations:
    meta.helm.sh/release-namespace: "default"
    meta.helm.sh/release-name: "reloader"
  labels:
    app: reloader-reloader
    chart: "reloader-1.0.51"
    release: "reloader"
    heritage: "Helm"
    app.kubernetes.io/managed-by: "Helm"
  name: reloader-reloader
  namespace: default
---
# Source: reloader/templates/clusterrole.yaml
apiVersion: rbac.authorization.k8s.io/v1

kind: ClusterRole
metadata:
  annotations:
    meta.helm.sh/release-namespace: "default"
    meta.helm.sh/release-name: "reloader"
  labels:
    app: reloader-reloader
    chart: "reloader-1.0.51"
    release: "reloader"
    heritage: "Helm"
    app.kubernetes.io/managed-by: "Helm"
  name: reloader-reloader-role
rules:
  - apiGroups:
      - ""
    resources:
      - secrets
      - configmaps
    verbs:
      - list
      - get
      - watch
  - apiGroups:
      - "apps"
    resources:
      - deployments
      - daemonsets
      - statefulsets
    verbs:
      - list
      - get
      - update
      - patch
  - apiGroups:
      - "extensions"
    resources:
      - deployments
      - daemonsets
    verbs:
      - list
      - get
      - update
      - patch
  - apiGroups:
      - "batch"
    resources:
      - cronjobs
    verbs:
      - list
      - get
  - apiGroups:
      - "batch"
    resources:
      - jobs
    verbs:
      - create
  - apiGroups:
      - ""
    resources:
      - events
    verbs:
      - create
      - patch
---
# Source: reloader/templates/clusterrolebinding.yaml
apiVersion: rbac.authorization.k8s.io/v1

kind: ClusterRoleBinding
metadata:
  annotations:
    meta.helm.sh/release-namespace: "default"
    meta.helm.sh/release-name: "reloader"
  labels:
    app: reloader-reloader
    chart: "reloader-1.0.51"
    release: "reloader"
    heritage: "Helm"
    app.kubernetes.io/managed-by: "Helm"
  name: reloader-reloader-role-binding
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: reloader-reloader-role
subjects:
  - kind: ServiceAccount
    name: reloader-reloader
    namespace: default
---
# Source: reloader/templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  annotations:
    meta.helm.sh/release-namespace: "default"
    meta.helm.sh/release-name: "reloader"
  labels:
    app: reloader-reloader
    chart: "reloader-1.0.51"
    release: "reloader"
    heritage: "Helm"
    app.kubernetes.io/managed-by: "Helm"
    group: com.stakater.platform
    provider: stakater
    version: v1.0.51
  name: reloader-reloader
  namespace: default
spec:
  replicas: 1
  revisionHistoryLimit: 2
  selector:
    matchLabels:
      app: reloader-reloader
      release: "reloader"
  template:
    metadata:
      labels:
        app: reloader-reloader
        chart: "reloader-1.0.51"
        release: "reloader"
        heritage: "Helm"
        app.kubernetes.io/managed-by: "Helm"
        group: com.stakater.platform
        provider: stakater
        version: v1.0.51
    spec:
      containers:
      - image: "ghcr.io/stakater/reloader:v1.0.51"
        imagePullPolicy: IfNotPresent
        name: reloader-reloader

        ports:
        - name: http
          containerPort: 9090
        livenessProbe:
          httpGet:
            path: /live
            port: http
          timeoutSeconds: 5
          failureThreshold: 5
          periodSeconds: 10
          successThreshold: 1
          initialDelaySeconds: 10
        readinessProbe:
          httpGet:
            path: /metrics
            port: http
          timeoutSeconds: 5
          failureThreshold: 5
          periodSeconds: 10
          successThreshold: 1
          initialDelaySeconds: 10

        securityContext:
          {}
      securityContext: 
        runAsNonRoot: true
        runAsUser: 65534
      serviceAccountName: reloader-reloader
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