Kubernetes 中的 MySQL 路由器即服务

Question

我想在 Kubernetes 中部署 MySQL-router 作为服务工作。

我的计划..

• 在 k8 中部署 MySQL-router 并使用LoadBalancer(MetalLB)将 MySQL-router 作为服务公开
• 在 k8 中运行的应用程序将mysql-router服务视为其数据库。
• MySQL-router 将应用程序数据发送到 InnoDB 集群外部。

我尝试使用以下方法进行部署：

apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql-router
  namespace: mysql-router
spec:
  replicas: 1 
  selector:
    matchLabels:
      app: mysql-router
  template:
    metadata:
      labels:
        app: mysql-router
        version: v1
    spec:
      containers:
      - name: mysql-router
        image: mysql/mysql-router
        env:
        - name: MYSQL_HOST
          value: "192.168.123.130"
        - name: MYSQL_PORT
          value: "3306"
        - name: MYSQL_USER
          value: "root"
        - name: MYSQL_PASSWORD
          value: "root@123"
        imagePullPolicy: Always
        ports:
        - containerPort: 6446

192.168.123.130 是 MySQL 集群主 IP。

apiVersion: v1
kind: Service
metadata:
  name: mysql-router-service
  namespace: mysql-router
  labels:
    app: mysql-router
spec:
  selector:
    app: mysql-router
  ports:
  - protocol: TCP
    port: 6446
  type: LoadBalancer
  loadBalancerIP: 192.168.123.123

当我检查mysql-router容器日志时，我看到如下内容：

Waiting for mysql server 192.168.123.130 (0/12)
Waiting for mysql server 192.168.123.130 (1/12)
Waiting for mysql server 192.168.123.130 (2/12)
....

在部署中设置我的外部 MySQL 集群信息后，我收到以下错误：

成功联系到mysql服务器192.168.123.130。检查集群状态。无法连接到数据库。退出。

mysql-router不指定就无法部署MYSQL_HOST。我在这里缺少什么？

我的理想部署

Answer 1

当然你必须提供MySQL Host。您可以使用服务中的k8s DNS哪个设置来执行此操作。

MySQL 路由器是中间件，可在您的应用程序和任何后端 MySQL 服务器之间提供透明路由。它可用于各种用例，例如通过有效地将数据库流量路由到适当的后端 MySQL 服务器来提供高可用性和可扩展性。

例子

对于下面的示例，我dynamic volume provisioning用于数据 using openebs-hostpathAnd usingStatefulSet用于 MySQL 服务器。

部署

MySQL路由器：

apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql-router
  namespace: mysql-router
spec:
  replicas: 1 
  selector:
    matchLabels:
      app: mysql-router
  template:
    metadata:
      labels:
        app: mysql-router
        version: v1
    spec:
      containers:
      - name: mysql-router
        image: mysql/mysql-router
        env:
        - name: MYSQL_HOST
          value: "mariadb-galera.galera-cluster"
        - name: MYSQL_PORT
          value: "3306"
        - name: MYSQL_USER
          value: "root"
        - name: MYSQL_PASSWORD
          value: "root@123"
        imagePullPolicy: Always
        ports:
        - containerPort: 3306

MySQL服务器

apiVersion: apps/v1
kind: StatefulSet
metadata:
  namespace: galera-cluster
  name: mariadb-galera
spec:
  podManagementPolicy: OrderedReady
  replicas: 1
  selector:
    matchLabels:
      app: mariadb-galera
  serviceName: mariadb-galera
  template:
    metadata:
      labels:
        app: mariadb-galera
    spec:
      restartPolicy: Always
      securityContext:
        fsGroup: 1001
        runAsUser: 1001
      containers:
      - command:
        - bash
        - -ec
        - |
          # Bootstrap from the indicated node
          NODE_ID="${MY_POD_NAME#"mariadb-galera-"}"
          if [[ "$NODE_ID" -eq "0" ]]; then
              export MARIADB_GALERA_CLUSTER_BOOTSTRAP=yes
              export MARIADB_GALERA_FORCE_SAFETOBOOTSTRAP=no
          fi
          exec /opt/bitnami/scripts/mariadb-galera/entrypoint.sh /opt/bitnami/scripts/mariadb-galera/run.sh
        env:
        - name: MY_POD_NAME
          valueFrom:
            fieldRef:
              apiVersion: v1
              fieldPath: metadata.name
        - name: BITNAMI_DEBUG
          value: "false"
        - name: MARIADB_GALERA_CLUSTER_NAME
          value: galera
        - name: MARIADB_GALERA_CLUSTER_ADDRESS
          value: gcomm://mariadb-galera.galera-cluster
        - name: MARIADB_ROOT_PASSWORD
          value: root@123
        - name: MARIADB_DATABASE
          value: my_database
        - name: MARIADB_GALERA_MARIABACKUP_USER
          value: mariabackup
        - name: MARIADB_GALERA_MARIABACKUP_PASSWORD
          value: root@123
        - name: MARIADB_ENABLE_LDAP
          value: "no"
        - name: MARIADB_ENABLE_TLS
          value: "no"
        image: docker.io/bitnami/mariadb-galera:10.4.13-debian-10-r23
        imagePullPolicy: IfNotPresent
        livenessProbe:
          exec:
            command:
            - bash
            - -ec
            - |
              exec mysqladmin status -uroot -p$MARIADB_ROOT_PASSWORD
          failureThreshold: 3
          initialDelaySeconds: 120
          periodSeconds: 10
          successThreshold: 1
          timeoutSeconds: 1
        name: mariadb-galera
        ports:
        - containerPort: 3306
          name: mysql
          protocol: TCP
        - containerPort: 4567
          name: galera
          protocol: TCP
        - containerPort: 4568
          name: ist
          protocol: TCP
        - containerPort: 4444
          name: sst
          protocol: TCP
        readinessProbe:
          exec:
            command:
            - bash
            - -ec
            - |
              exec mysqladmin status -uroot -p$MARIADB_ROOT_PASSWORD
          failureThreshold: 3
          initialDelaySeconds: 30
          periodSeconds: 10
          successThreshold: 1
          timeoutSeconds: 1
        volumeMounts:
        - mountPath: /opt/bitnami/mariadb/.bootstrap
          name: previous-boot
        - mountPath: /bitnami/mariadb
          name: data
        - mountPath: /opt/bitnami/mariadb/conf
          name: mariadb-galera-config
      volumes:
      - emptyDir: {}
        name: previous-boot
      - configMap:
          defaultMode: 420
          name: my.cnf
        name: mariadb-galera-config
  volumeClaimTemplates:
  - apiVersion: v1
    metadata:
      name: data
    spec:
      storageClassName: openebs-hostpath
      accessModes:
      - ReadWriteOnce
      resources:
        requests:
          storage: 20Gi

服务

MySQL 路由器服务

apiVersion: v1
kind: Service
metadata:
  name: mysql-router-service
  namespace: mysql-router
  labels:
    app: mysql-router
spec:
  selector:
    app: mysql-router
  ports:
  - protocol: TCP
    port: 3306
  type: LoadBalancer
  loadBalancerIP: 192.168.123.123

MySQL服务

apiVersion: v1
kind: Service
metadata:
  namespace: galera-cluster
  name: mariadb-galera
  labels:
    app: mariadb-galera
spec:
  type: ClusterIP
  ports:
  - name: mysql
    port: 3306
  selector:
    app: mariadb-galera
---
apiVersion: v1
kind: Service
metadata:
  namespace: galera-cluster
  name: mariadb-galera-headless
  labels:
    app: mariadb-galera
spec:
  type: ClusterIP
  ports:
  - name: galera
    port: 4567
  - name: ist
    port: 4568
  - name: sst
    port: 4444
  selector:
    app: mariadb-galera

Answer 2

您需要的#1是从App1-x到Mysql路由器的通信，#2是从MysqlRoutere到外部mysql实例的VIP/LB。

我们从 Mysql 实例 VIP 的 #2 配置开始。您将需要一个没有选择器的服务。

apiVersion: v1
kind: Service
metadata:
  name: mysql-service
spec:
  ports:
  - name: mysql
    port: 3306
    protocol: TCP
    targetPort: 3306
  sessionAffinity: None
  type: ClusterIP
---
apiVersion: v1
kind: Endpoints
metadata:
  name: mysql-service
subsets:
- addresses:
  - ip: 192.168.123.130
  - ip: 192.168.123.131
  - ip: 192.168.123.132
  ports:
  - name: mysql
    port: 3306
    protocol: TCP

您不需要LoadBalancer，因为您将仅在集群内部连接。所以，改用ClusterIp吧。

#1 创建 MysqlRouter 部署。

apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql-router
  namespace: mysql-router
spec:
  replicas: 1 
  selector:
    matchLabels:
      app: mysql-router
  template:
    metadata:
      labels:
        app: mysql-router
        version: v1
    spec:
      containers:
      - name: mysql-router
        image: mysql/mysql-router
        env:
        - name: MYSQL_HOST
          value: "mysql-service"
        - name: MYSQL_PORT
          value: "3306"
        - name: MYSQL_USER
          value: "root"
        - name: MYSQL_PASSWORD
          value: "root@123"
        imagePullPolicy: Always
        ports:
        - containerPort: 6446

要通过 VIP/ClusterIP 使用服务连接到外部 MySQL 实例mysql-service，如果部署和服务位于同一命名空间中，请使用mysql-service主机名或在其中放置一个CLusterIPfromkubectl get service mysql-service

apiVersion: v1
kind: Service
metadata:
  name: mysql-router-service
  namespace: mysql-router
  labels:
    app: mysql-router
spec:
  selector:
    app: mysql-router
  ports:
  - name: mysql
    port: 6446
    protocol: TCP
    targetPort: 6446
  type: ClusterIP

您可以在 kubernetes 集群内连接到mysql-router-service同一命名空间中的主机名，以及使用外部命名空间mysql-router-service.namespace.svc或在 kubernetes 集群外部使用NodePort或LoadBalancer。