k8s部署MySQL主从数据库

参考：https://kubernetes.io/zh-cn/docs/tasks/run-application/run-replicated-stateful-application/

我的测试集群

root@master:~/mysql# kubectl get nodes -owide
NAME     STATUS   ROLES                  AGE    VERSION   INTERNAL-IP     EXTERNAL-IP   OS-IMAGE             KERNEL-VERSION      CONTAINER-RUNTIME
master   Ready    control-plane,master   136d   v1.23.4   192.168.0.101   <none>        Ubuntu 20.04.4 LTS   5.15.0-46-generic   docker://20.10.12
node1    Ready    <none>                 136d   v1.23.4   192.168.0.102   <none>        Ubuntu 20.04.4 LTS   5.15.0-46-generic   docker://20.10.12
node2    Ready    <none>                 136d   v1.23.4   192.168.0.103   <none>        Ubuntu 20.04.4 LTS   5.15.0-46-generic   docker://20.10.12

1、创建PV

root@master:~/mysql# cat persistentVolume.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
  name: example-mysql-pv
spec:
  capacity:
    storage: 5Gi
  volumeMode: Filesystem
  accessModes:
  - ReadWriteOnce
  persistentVolumeReclaimPolicy: Delete
  storageClassName: local-storage
  local:
    path: /data/svr/projects/mysql
  nodeAffinity:
    required:
      nodeSelectorTerms:
      - matchExpressions:
        - key: kubernetes.io/hostname
          operator: In
          values:
          - node1
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: example-mysql-pv-2
spec:
  capacity:
    storage: 5Gi
  volumeMode: Filesystem
  accessModes:
  - ReadWriteOnce
  persistentVolumeReclaimPolicy: Delete
  storageClassName: local-storage
  local:
    path: /data/svr/projects/mysql2
  nodeAffinity:
    required:
      nodeSelectorTerms:
      - matchExpressions:
        - key: kubernetes.io/hostname
          operator: In
          values:
          - node1
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: example-mysql-pv-3
spec:
  capacity:
    storage: 5Gi
  volumeMode: Filesystem
  accessModes:
  - ReadWriteOnce
  persistentVolumeReclaimPolicy: Delete
  storageClassName: local-storage
  local:
    path: /data/svr/projects/mysql3
  nodeAffinity:
    required:
      nodeSelectorTerms:
      - matchExpressions:
        - key: kubernetes.io/hostname
          operator: In
          values:
          - node1
root@master:~/mysql# kubectl apply -f persistentVolume.yaml

2、创建sc

root@master:~/mysql# cat storageclass.yaml
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: local-storage
provisioner: kubernetes.io/no-provisioner
volumeBindingMode: WaitForFirstConsumer
root@master:~/mysql# kubectl apply -f storageclass.yaml

3、创建ns

root@master:~/mysql# cat mysql-namespace.yaml
apiVersion: v1
kind: Namespace
metadata:
  name: mysql
  labels:
    app: mysql
root@master:~/mysql# kubectl apply -f mysql-namespace.yaml

4、创建一个cm

root@master:~/mysql# cat mysql-configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql
  namespace: mysql
  labels:
    app: mysql
data:
  master.cnf: |
    # 主库配置
    [mysqld]
    log-bin=mysqllog
    skip-name-resolve
  slave.cnf: |
    # 从库配置
    [mysqld]
    super-read-only
    skip-name-resolve
    log-bin=mysql-bin
    replicate-ignore-db=mysql
root@master:~/mysql# kubectl apply -f mysql-configmap.yaml

5、创建secret

root@master:~/mysql# cat 05-mysql-secret.yaml
apiVersion: v1
kind: Secret
metadata:
  name: mysql-secret
  namespace: mysql
  labels:
    app: mysql
type: Opaque
data:
  password: MTIzNDU2 # echo -n "123456" | base64
root@master:~/mysql# kubectl apply -f mysql-secret.yaml

6、创建service

root@master:~/mysql# cat mysql-service.yaml
# 为 StatefulSet 成员提供稳定的 DNS 表项的无头服务（Headless Service）
apiVersion: v1
kind: Service
metadata:
  name: mysql
  namespace: mysql
  labels:
    app: mysql
spec:
  ports:
  - name: mysql
    port: 3306
  clusterIP: None
  selector:
    app: mysql
---
# 用于连接到任一 MySQL 实例执行读操作的客户端服务
# 对于写操作，你必须连接到主服务器：mysql-0.mysql
apiVersion: v1
kind: Service
metadata:
  name: mysql-read
  namespace: mysql
  labels:
    app: mysql
spec:
  ports:
  - name: mysql
    port: 3306
  selector:
    app: mysql
root@master:~/mysql# kubectl apply -f mysql-service.yaml

7、创建statefulset

root@master:~/mysql# cat mysql-statefulset.yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mysql
  namespace: mysql
  labels:
    app: mysql
spec:
  selector:
    matchLabels:
      app: mysql
  serviceName: mysql
  replicas: 2
  template:
    metadata:
      labels:
        app: mysql
    spec:
      initContainers:
      - name: init-mysql
        image: mysql:5.7
        env:
        - name: MYSQL_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysql-secret
              key: password
        command:
        - bash
        - "-c"
        - |
          set -ex
          # 基于 Pod 序号生成 MySQL 服务器的 ID。
          [[ `hostname` =~ -([0-9]+)$ ]] || exit 1
          ordinal=${BASH_REMATCH[1]}
          echo [mysqld] > /mnt/conf.d/server-id.cnf
          # # 添加偏移量以避免使用 server-id=0 这一保留值。由于 server-id 不能为 0，因此给 ID 加 100 来避开它
          echo server-id=$((100 + $ordinal)) >> /mnt/conf.d/server-id.cnf
          # 如果 Pod 的序号为 0，说明它是 Master 节点，从 ConfigMap 里把 Master 的配置文件拷贝到 /mnt/conf.d 目录下
          # 否则，拷贝 ConfigMap 里的 Slave 的配置文件
          if [[ $ordinal == 0  ]]; then
            cp /mnt/config-map/master.cnf /mnt/conf.d
          else
            cp /mnt/config-map/slave.cnf /mnt/conf.d
          fi
        volumeMounts:
        - name: conf
          mountPath: /mnt/conf.d
        - name: config-map
          mountPath: /mnt/config-map
      - name: clone-mysql
        #image: gcr.io/google-samples/xtrabackup:1.0
        image: registry.cn-shenzhen.aliyuncs.com/jbjb/csi:xtrabackup-1.0
        env:
        - name: MYSQL_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysql-secret
              key: password
        command:
        - bash
        - "-c"
        - |
          set -ex
          # 拷贝操作只需要在第一次启动时进行，所以数据已经存在则跳过
          [[ -d /var/lib/mysql/mysql ]] && exit 0
          # Master 节点（序号为 ）不需要这个操作，跳过主实例（序号索引 0）的克隆。
          [[ $(hostname) =~ -([0-9]+)$ ]] || exit 1
          ordinal=${BASH_REMATCH[1]}
          [[ $ordinal == 0 ]] && exit
          # 从原来的对等节点克隆数据。使用 ncat 指令，远程地从前一个节点拷贝数据到本地
          ncat --recv-only mysql-$(($ordinal-1)).mysql 3307 | xbstream -x -C /var/lib/mysql
          # 准备备份。执行 --prepare，这样拷贝来的数据就可以用作恢复了
          xtrabackup --prepare --target-dir=/var/lib/mysql
        volumeMounts:
        - name: data
          mountPath: /var/lib/mysql
          subPath: mysql
        - name: conf
          mountPath: /etc/mysql/conf.d
      containers:
      - name: mysql
        image: mysql:5.7
        env:
#        - name: MYSQL_ALLOW_EMPTY_PASSWORD
#          value: "1"
        - name: MYSQL_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysql-secret
              key: password
        ports:
        - name: mysql
          containerPort: 3306
        volumeMounts:
        - name: data
          mountPath: /var/lib/mysql
          subPath: mysql
        - name: conf
          mountPath: /etc/mysql/conf.d
        resources:
          requests:
            cpu: 500m
            memory: 0.5Gi
        livenessProbe:
          exec:
            command: ["mysqladmin", "ping", "-uroot", "-p${MYSQL_ROOT_PASSWORD}"]
          initialDelaySeconds: 30
          periodSeconds: 10
          timeoutSeconds: 5
        readinessProbe:
          exec:
            command: ["mysqladmin", "ping", "-uroot", "-p${MYSQL_ROOT_PASSWORD}"]
          initialDelaySeconds: 5
          periodSeconds: 2
          timeoutSeconds: 1
      - name: xtrabackup
        image: registry.cn-shenzhen.aliyuncs.com/jbjb/csi:xtrabackup-1.0
        ports:
        - name: xtrabackup
          containerPort: 3307
        env:
        - name: MYSQL_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysql-secret
              key: password
        command:
        - bash
        - "-c"
        - |
          set -ex
          cd /var/lib/mysql
          # 从备份信息文件里读取 MASTER_LOG_FILE 和 MASTER_LOG_POS 这 2 个字段的值，用来拼装集群初始化 SQL
          if [[ -f xtrabackup_slave_info ]]; then
            # 如果 xtrabackup_slave_info 文件存在，说明这个备份数据来自于另一个 Slave 节点
            # 这种情况下，XtraBackup 工具在备份的时候，就已经在这个文件里自动生成了 "CHANGE MASTER TO" SQL 语句
            # 所以，只需要把这个文件重命名为 change_master_to.sql.in，后面直接使用即可
            mv xtrabackup_slave_info change_master_to.sql.in
            # 所以，也就用不着 xtrabackup_binlog_info 了
            rm -f xtrabackup_binlog_info
          elif [[ -f xtrabackup_binlog_info ]]; then
            # 如果只是存在 xtrabackup_binlog_info 文件，说明备份来自于 Master 节点，就需要解析这个备份信息文件，读取所需的两个字段的值
            [[ $(cat xtrabackup_binlog_info) =~ ^(.*?)[[:space:]]+(.*?)$ ]] || exit 1
            rm xtrabackup_binlog_info
            # 把两个字段的值拼装成 SQL，写入 change_master_to.sql.in 文件
            echo "CHANGE MASTER TO MASTER_LOG_FILE='${BASH_REMATCH[1]}',\
                  MASTER_LOG_POS=${BASH_REMATCH[2]}" > change_master_to.sql.in
          fi
          # 如果存在 change_master_to.sql.in，就意味着需要做集群初始化工作
          if [[ -f change_master_to.sql.in ]]; then
            # 但一定要先等 MySQL 容器启动之后才能进行下一步连接 MySQL 的操作
            echo "Waiting for mysqld to be ready（accepting connections）"
            until mysql -h 127.0.0.1 -uroot -p${MYSQL_ROOT_PASSWORD} -e "SELECT 1"; do sleep 1; done
            echo "Initializing replication from clone position"
            # 将文件 change_master_to.sql.in 改个名字
            # 防止这个 Container 重启的时候，因为又找到了 change_master_to.sql.in，从而重复执行一遍初始化流程
            mv change_master_to.sql.in change_master_to.sql.orig
            # 使用 change_master_to.sql.orig 的内容，也就是前面拼装的 SQL，组成一个完整的初始化和启动 Slave 的 SQL 语句
            mysql -h 127.0.0.1 -uroot -p${MYSQL_ROOT_PASSWORD} << EOF
          $(< change_master_to.sql.orig),
            MASTER_HOST='mysql-0.mysql.mysql',
            MASTER_USER='root',
            MASTER_PASSWORD='${MYSQL_ROOT_PASSWORD}',
            MASTER_CONNECT_RETRY=10;
          START SLAVE;
          EOF
          fi
          # 使用 ncat 监听 3307 端口。
          # 它的作用是，在收到传输请求的时候，直接执行 xtrabackup --backup 命令，备份 MySQL 的数据并发送给请求者
          exec ncat --listen --keep-open --send-only --max-conns=1 3307 -c \
            "xtrabackup --backup --slave-info --stream=xbstream --host=127.0.0.1 --user=root --password=${MYSQL_ROOT_PASSWORD}"
        volumeMounts:
        - name: data
          mountPath: /var/lib/mysql
          subPath: mysql
        - name: conf
          mountPath: /etc/mysql/conf.d
      volumes:
      - name: conf
        emptyDir: {}
      - name: config-map
        configMap:
          name: mysql
  volumeClaimTemplates:
  - metadata:
      name: data
    spec:
      accessModes:
      - "ReadWriteOnce"
      storageClassName: local-storage
      resources:
        requests:
          storage: 5Gi
root@master:~/mysql# kubectl apply -f mysql-statefulset.yaml

8、验证

root@master:~/mysql# kubectl get all -n mysql
NAME          READY   STATUS    RESTARTS   AGE
pod/mysql-0   2/2     Running   0          21d
pod/mysql-1   2/2     Running   0          21d

NAME                 TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)    AGE
service/mysql        ClusterIP   None             <none>        3306/TCP   25d
service/mysql-read   ClusterIP   10.108.100.108   <none>        3306/TCP   25d

NAME                     READY   AGE
statefulset.apps/mysql   2/2     21d
root@master:~# kubectl get pv -o wide
NAME                 CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM                 STORAGECLASS    REASON   AGE   VOLUMEMODE
example-mysql-pv     5Gi        RWO            Delete           Bound       mysql/data-mysql-0    local-storage            25d   Filesystem
example-mysql-pv-2   5Gi        RWO            Delete           Bound       mysql/data-mysql-1    local-storage            25d   Filesystem
example-mysql-pv-3   5Gi        RWO            Delete           Available                         local-storage            25d   Filesystem