k8s 搭建 MySQL 主从失败

nfs 作为存储，pvc 和 pv 都是 bound 状态，而且还测试过 pod 都能够向 nfs 里面写入文件，但搭建 mysql 就报错：

Events:
  Type     Reason            Age                  From               Message
  ----     ------            ----                 ----               -------
  Warning  FailedScheduling  25m                  default-scheduler  0/4 nodes are available: 4 pod has unbound immediate PersistentVolumeClaims. preemption: 0/4 nodes are available: 4 Preemption is not helpful for scheduling.
  Normal   Scheduled         25m                  default-scheduler  Successfully assigned lzipant/mysql-0 to arch124
  Normal   Pulling           25m                  kubelet            Pulling image "mysql:5.7"
  Normal   Pulled            25m                  kubelet            Successfully pulled image "mysql:5.7" in 3.099960834s
  Normal   Created           24m (x5 over 25m)    kubelet            Created container init-mysql
  Normal   Pulled            24m (x4 over 25m)    kubelet            Container image "mysql:5.7" already present on machine
  Normal   Started           24m (x5 over 25m)    kubelet            Started container init-mysql
  Warning  BackOff           43s (x117 over 25m)  kubelet            Back-off restarting failed container

各项 yaml 如下：

configMap.yaml:

apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql
  namespace: lzipant
  labels:
    app: mysql
data:
  master.cnf: |
    [mysqld]
    log-bin
  slave.cnf: |
    [mysqld]
    super-read-only

service.yaml:

apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql
  namespace: lzipant
  labels:
    app: mysql
data:
  master.cnf: |
    [mysqld]
    log-bin
  slave.cnf: |
    [mysqld]
    super-read-only

statefulSet.yaml：

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mysql
  namespace: lzipant
spec:
  selector:
    matchLabels:
      # 适用于所有 label 包括 app=mysql 的 pod
      app: mysql
  serviceName: mysql
  replicas: 3

  #  定义 pod
  template:
    metadata:
      labels:
        app: mysql
    spec:
      # 在 init 容器中为 pod 中的 mysql 容器做初始化工作
      initContainers:
        # init-mysql 容器会分配 pod 的角色是 master 还是 slave, 然后生成配置文件
        - name: init-mysql
          image: mysql:5.7
          command:
            - bash
            - "-c"
            - |
              set -ex
              # 生成 server-id
              [[ `hostname` =~ -([0-9]+)$ ]] || exit 1
              ordinal=${BASH_REMATCH[1]}
              echo [mysqld] > /mnt/conf.d/server-id.cnf
              # 写入 server-id
              echo server-id=$((100 + $ordinal)) >> /mnt/conf.d/server-id.cnf
              # server-id 尾号为 0 作为 master, 否则作为 slave
              # 这里 cp 到 pod 中的 cnf 会与 server-id.cnf 一块被 mysql.cnf  include 进去
              # 这里指定了序号为 0 的 pod 会作为 master 节点提供写, 其他 pod 作为 slave 节点提供读
              if [[ $ordinal -eq 0 ]]; then
                cp /mnt/config-map/master.cnf /mnt/conf.d/
              else
                cp /mnt/config-map/slave.cnf /mnt/conf.d/
              fi
          volumeMounts:
            # 将 conf 临时卷挂载到了 pod 的 /mnt/conf.d 路径下
            - name: conf
              mountPath: /mnt/conf.d
            # 这里把 ConfigMap 中的配置怪哉到了 pod 的 /mnt/config-map 路径下
            - name: config-map
              mountPath: /mnt/config-map
        # 这一个 init 容器会正在 pod 启动时假定之前已经存在数据, 并将之前的数据复制过来, 以确保新 pod 中有数据可以提供使用
        - name: clone-mysql
          # xtrabackup 是一个开源工具, 用于克隆 mysql 的数据
          image: ist0ne/xtrabackup:latest
          command:
            - bash
            - "-c"
            - |
              set -ex
              # Skip the clone if data already exists.
              [[ -d /var/lib/mysql/mysql ]] && exit 0
              # Skip the clone on master (ordinal index 0).
              [[ `hostname` =~ -([0-9]+)$ ]] || exit 1
              ordinal=${BASH_REMATCH[1]}
              [[ $ordinal -eq 0 ]] && exit 0
              # Clone data from previous peer.
              ncat --recv-only mysql-$(($ordinal-1)).mysql 3307 | xbstream -x -C /var/lib/mysql
              # Prepare the backup.
              xtrabackup --prepare --target-dir=/var/lib/mysql
          volumeMounts:
            - name: mysql-data
              mountPath: /var/lib/mysql
              subPath: mysql
            - name: conf
              mountPath: /etc/mysql/conf.d
      containers:
        # 实际运行 mysqld 服务的 mysql 容器
        - name: mysql
          image: mysql:5.7
          env:
            - name: MYSQL_ROOT_PASSWORD
              value: "abcdef"
          ports:
            - name: mysql
              containerPort: 3306
          volumeMounts:
            # 将 data 卷的 mysql 目录挂在到容器的 /var/lib/mysql
            - name: mysql-data
              mountPath: /var/lib/mysql
              subPath: mysql
            - name: conf
              mountPath: /etc/mysql/conf.d
          resources:
            requests:
              cpu: 500m
              memory: 1Gi
          # 启动存活探针, 如果失败会重启 pod
          livenessProbe:
            exec:
              command: ["mysqladmin", "ping"]
            initialDelaySeconds: 30
            periodSeconds: 10
            timeoutSeconds: 5
          # 启动就绪探针确保容器的运行正常, 如果有失败会将 pod 从 service 关联的 endpoint 中剔除
          readinessProbe:
            exec:
              # Check we can execute queries over TCP (skip-networking is off).
              command: ["mysql", "-h", "127.0.0.1", "-e", "SELECT 1"]
            initialDelaySeconds: 5
            periodSeconds: 2
            timeoutSeconds: 1
        # init 结束后还会在启动一个 xtrabackup 容器作为 mysqld 容器的 sidecar 运行
        - name: xtrabackup
          image: ist0ne/xtrabackup:latest
          ports:
            - name: xtrabackup
              containerPort: 3307
          command:
            - bash
            - "-c"
            - |
              set -ex
              cd /var/lib/mysql
              # 他会在启动时查看之前是否有数据克隆文件存在, 如果有那就去其他从节点复制数据, 如果没有就去主节点复制数据
              # Determine binlog position of cloned data, if any.
              if [[ -f xtrabackup_slave_info && "x$(<xtrabackup_slave_info)" != "x" ]]; then
                # XtraBackup already generated a partial "CHANGE MASTER TO" query
                # because we're cloning from an existing slave. (Need to remove the tailing semicolon!)
                cat xtrabackup_slave_info | sed -E 's/;$//g' > change_master_to.sql.in
                # Ignore xtrabackup_binlog_info in this case (it's useless).
                rm -f xtrabackup_slave_info xtrabackup_binlog_info
              elif [[ -f xtrabackup_binlog_info ]]; then
                # We're cloning directly from master. Parse binlog position.
                [[ `cat xtrabackup_binlog_info` =~ ^(.*?)[[:space:]]+(.*?)$ ]] || exit 1
                rm -f xtrabackup_binlog_info xtrabackup_slave_info
                echo "CHANGE MASTER TO MASTER_LOG_FILE='${BASH_REMATCH[1]}',\
                      MASTER_LOG_POS=${BASH_REMATCH[2]}" > change_master_to.sql.in
              fi

              # Check if we need to complete a clone by starting replication.
              if [[ -f change_master_to.sql.in ]]; then
                echo "Waiting for mysqld to be ready (accepting connections)"
                until mysql -h 127.0.0.1 -e "SELECT 1"; do sleep 1; done

                echo "Initializing replication from clone position"
                mysql -h 127.0.0.1 \
                      -e "$(<change_master_to.sql.in), \
                              MASTER_HOST='mysql-0.mysql', \
                              MASTER_USER='root', \
                              MASTER_PASSWORD='', \
                              MASTER_CONNECT_RETRY=10; \
                            START SLAVE;" || exit 1
                # In case of container restart, attempt this at-most-once.
                mv change_master_to.sql.in change_master_to.sql.orig
              fi

              # Start a server to send backups when requested by peers.
              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"
          volumeMounts:
            # 将 data 卷的 mysql 目录挂在到容器的 /var/lib/mysql
            - name: mysql-data
              mountPath: /var/lib/mysql
              subPath: mysql
            - name: conf
              mountPath: /etc/mysql/conf.d
      volumes:
        - name: conf
          # pod 在节点上被移除时, emptyDir 会同时被删除
          # emptyDir 一般被用作缓存目录,  这里用在 config
          emptyDir: {}
        - name: config-map
          # ConfigMap 对象中存储的数据可以被 configMap 类型的卷引用, 然后被 Pod 中运行的容器使用
          # 这里引用了前面定义了名称为 mysql 的 ConfigMap 对象
          configMap:
            name: mysql

  volumeClaimTemplates:
    # 这里面定义的是对 PVC 的模板, 这里没有单独为 mysql 创建 pvc, 而是动态创建的
    - metadata:
        name: mysql-data
        namespace: lzipant
      spec:
        accessModes: ["ReadWriteOnce"]
        # 如果没有配置默认的 storageClass 的话, 需要指定 storageClassName
        storageClassName: managed-nfs-storage
        resources:
          requests:
            storage: 5Gi

storageClass.yaml:

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: managed-nfs-storage
  namespace: lzipant
provisioner: fuseim.pri/ifs # must match deployement env PROVISIONER_NAME
reclaimPolicy: Retain