1、前言

Pod调度运⾏时，如果应⽤不需要任何稳定的标示、有序的部署、删除和扩展，则应该使⽤⼀组⽆状态副本的控制器来部署应⽤，例如 Deployment 或 ReplicaSet更适合⽆状态服务需求，⽽StatefulSet适合管理所有有状态的服务，⽐如MySQL、MongoDB集群等。

2、StatefulSet控制器运行MySQL一主多从架构图

StatefulSet本质上是Deployment的⼀种变体，在v1.9版本中已成为GA版本，它为了解决有状态服务的问题，它所管理的Pod拥有固定的Pod名称，启停顺序，在StatefulSet中，Pod名字称为⽹络标识(hostname)，还必须要⽤到共享存储。
在Deployment中，与之对应的服务是service，⽽在StatefulSet中与之对应的headless service，headless service，即⽆头服务，与service的区别就是它没有Cluster IP，解析它的名称时将返回该Headless Service对应的全部Pod的Endpoint列表。

2.1、StatefulSet控制器特点

• 给每个pod分配固定且唯⼀的⽹络标识符
• 给每个pod分配固定且持久化的外部存储
• 对pod进⾏有序的部署和扩展
• 对pod进有序的删除和终⽌
• 对pod进有序的⾃动滚动更新

2.2、StatefulSet的组成部分

• Headless Service：⽤来定义Pod⽹络标识( DNS domain)，指的是短的service(丢失了domainname)。
• StatefulSet：定义具体应⽤，有多少个Pod副本，并为每个Pod定义了⼀个域名。
• volumeClaimTemplates： 存储卷申请模板，创建PVC，指定pvc名称⼤⼩，将⾃动创建pvc，且pvc必须由存储类供应。

3、在k8s上部署mysql一主多从

3.1、基础镜像准备

3.1.1、准备mysql镜像

下载镜像

root@k8s-master01:~# nerdctl pull mysql:5.7.36

修改镜像tag为本地harbor地址

root@k8s-master01:~# nerdctl tag mysql:5.7.36 harbor.ik8s.cc/magedu/mysql:5.7.36

上传镜像至本地harbor

root@k8s-master01:~# nerdctl push harbor.ik8s.cc/magedu/mysql:5.7.36

3.1.2、准备xtrabackup镜像

下载镜像

root@k8s-master01:~# nerdctl pull registry.cn-hangzhou.aliyuncs.com/hxpdocker/xtrabackup:1.0

修改镜像tag为本地harbor地址

root@k8s-master01:~# nerdctl tag registry.cn-hangzhou.aliyuncs.com/hxpdocker/xtrabackup:1.0 harbor.ik8s.cc/magedu/xtrabackup:1.0

上传镜像至本地harbor

root@k8s-master01:~# nerdctl push harbor.ik8s.cc/magedu/xtrabackup:1.0

3.1.3、验证镜像是否上传至harbor？

3.2、准备pv

3.2.1、在nfs服务器上创建数据存储目录

root@harbor:~# mkdir -pv /data/k8sdata/magedu/mysql-datadir-{1..5}
mkdir: created directory '/data/k8sdata/magedu/mysql-datadir-1'
mkdir: created directory '/data/k8sdata/magedu/mysql-datadir-2'
mkdir: created directory '/data/k8sdata/magedu/mysql-datadir-3'
mkdir: created directory '/data/k8sdata/magedu/mysql-datadir-4'
mkdir: created directory '/data/k8sdata/magedu/mysql-datadir-5'
root@harbor:~# 

3.2.2、在nfs服务器上导出数据存储目录

root@harbor:/data/k8sdata/magedu# cat /etc/exports 
# /etc/exports: the access control list for filesystems which may be exported
#               to NFS clients.  See exports(5).
#
# Example for NFSv2 and NFSv3:
# /srv/homes       hostname1(rw,sync,no_subtree_check) hostname2(ro,sync,no_subtree_check)
#
# Example for NFSv4:
# /srv/nfs4        gss/krb5i(rw,sync,fsid=0,crossmnt,no_subtree_check)
# /srv/nfs4/homes  gss/krb5i(rw,sync,no_subtree_check)
#
/data/k8sdata/kuboard *(rw,no_root_squash)
/data/volumes *(rw,no_root_squash)
/pod-vol *(rw,no_root_squash)
/data/k8sdata/myserver *(rw,no_root_squash)
/data/k8sdata/mysite *(rw,no_root_squash)

/data/k8sdata/magedu/images *(rw,no_root_squash)
/data/k8sdata/magedu/static *(rw,no_root_squash)


/data/k8sdata/magedu/zookeeper-datadir-1 *(rw,no_root_squash)
/data/k8sdata/magedu/zookeeper-datadir-2 *(rw,no_root_squash)
/data/k8sdata/magedu/zookeeper-datadir-3 *(rw,no_root_squash)


/data/k8sdata/magedu/redis-datadir-1 *(rw,no_root_squash) 

/data/k8sdata/magedu/redis0 *(rw,no_root_squash)
/data/k8sdata/magedu/redis1 *(rw,no_root_squash)
/data/k8sdata/magedu/redis2 *(rw,no_root_squash)
/data/k8sdata/magedu/redis3 *(rw,no_root_squash)
/data/k8sdata/magedu/redis4 *(rw,no_root_squash)
/data/k8sdata/magedu/redis5 *(rw,no_root_squash)



/data/k8sdata/magedu/mysql-datadir-1 *(rw,no_root_squash)
/data/k8sdata/magedu/mysql-datadir-2 *(rw,no_root_squash)
/data/k8sdata/magedu/mysql-datadir-3 *(rw,no_root_squash)
/data/k8sdata/magedu/mysql-datadir-4 *(rw,no_root_squash)
/data/k8sdata/magedu/mysql-datadir-5 *(rw,no_root_squash)
root@harbor:/data/k8sdata/magedu# exportfs -av
exportfs: /etc/exports [1]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/kuboard".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [2]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/volumes".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [3]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/pod-vol".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [4]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/myserver".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [5]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/mysite".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [7]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/images".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [8]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/static".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [11]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/zookeeper-datadir-1".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [12]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/zookeeper-datadir-2".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [13]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/zookeeper-datadir-3".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [16]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/redis-datadir-1".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [18]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/redis0".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [19]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/redis1".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [20]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/redis2".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [21]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/redis3".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [22]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/redis4".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [23]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/redis5".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [27]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/mysql-datadir-1".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [28]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/mysql-datadir-2".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [29]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/mysql-datadir-3".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [30]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/mysql-datadir-4".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [31]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/mysql-datadir-5".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exporting *:/data/k8sdata/magedu/mysql-datadir-5
exporting *:/data/k8sdata/magedu/mysql-datadir-4
exporting *:/data/k8sdata/magedu/mysql-datadir-3
exporting *:/data/k8sdata/magedu/mysql-datadir-2
exporting *:/data/k8sdata/magedu/mysql-datadir-1
exporting *:/data/k8sdata/magedu/redis5
exporting *:/data/k8sdata/magedu/redis4
exporting *:/data/k8sdata/magedu/redis3
exporting *:/data/k8sdata/magedu/redis2
exporting *:/data/k8sdata/magedu/redis1
exporting *:/data/k8sdata/magedu/redis0
exporting *:/data/k8sdata/magedu/redis-datadir-1
exporting *:/data/k8sdata/magedu/zookeeper-datadir-3
exporting *:/data/k8sdata/magedu/zookeeper-datadir-2
exporting *:/data/k8sdata/magedu/zookeeper-datadir-1
exporting *:/data/k8sdata/magedu/static
exporting *:/data/k8sdata/magedu/images
exporting *:/data/k8sdata/mysite
exporting *:/data/k8sdata/myserver
exporting *:/pod-vol
exporting *:/data/volumes
exporting *:/data/k8sdata/kuboard
root@harbor:/data/k8sdata/magedu# 

3.2.2、创建pv

创建pv配置清单

---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-datadir-1
  namespace: magedu
spec:
  capacity:
    storage: 50Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    path: /data/k8sdata/magedu/mysql-datadir-1 
    server: 192.168.0.42
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-datadir-2
  namespace: magedu
spec:
  capacity:
    storage: 50Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    path: /data/k8sdata/magedu/mysql-datadir-2
    server: 192.168.0.42
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-datadir-3
  namespace: magedu
spec:
  capacity:
    storage: 50Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    path: /data/k8sdata/magedu/mysql-datadir-3
    server: 192.168.0.42
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-datadir-4
  namespace: magedu
spec:
  capacity:
    storage: 50Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    path: /data/k8sdata/magedu/mysql-datadir-4
    server: 192.168.0.42
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-datadir-5
  namespace: magedu
spec:
  capacity:
    storage: 50Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    path: /data/k8sdata/magedu/mysql-datadir-5
    server: 192.168.0.42

创建pv

root@k8s-master01:~/k8s-data/yaml/magedu/mysql# kubectl apply -f pv/mysql-persistentvolume.yaml
persistentvolume/mysql-datadir-1 created
persistentvolume/mysql-datadir-2 created
persistentvolume/mysql-datadir-3 created
persistentvolume/mysql-datadir-4 created
persistentvolume/mysql-datadir-5 created
root@k8s-master01:~/k8s-data/yaml/magedu/mysql#

3.2.3、验证pv

root@k8s-master01:~/k8s-data/yaml/magedu/mysql# kubectl get pv
NAME                     CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM                            STORAGECLASS   REASON   AGE
mysql-datadir-1          50Gi       RWO            Retain           Available                                                            5s
mysql-datadir-2          50Gi       RWO            Retain           Available                                                            5s
mysql-datadir-3          50Gi       RWO            Retain           Available                                                            5s
mysql-datadir-4          50Gi       RWO            Retain           Available                                                            5s
mysql-datadir-5          50Gi       RWO            Retain           Available                                                            5s
redis-cluster-pv0        5Gi        RWO            Retain           Bound       magedu/data-redis-1                                      8d
redis-cluster-pv1        5Gi        RWO            Retain           Bound       magedu/data-redis-3                                      8d
redis-cluster-pv2        5Gi        RWO            Retain           Bound       magedu/data-redis-4                                      8d
redis-cluster-pv3        5Gi        RWO            Retain           Bound       magedu/data-redis-0                                      8d
redis-cluster-pv4        5Gi        RWO            Retain           Bound       magedu/data-redis-5                                      8d
redis-cluster-pv5        5Gi        RWO            Retain           Bound       magedu/data-redis-2                                      8d
redis-datadir-pv-1       10Gi       RWO            Retain           Bound       magedu/redis-datadir-pvc-1                               9d
zookeeper-datadir-pv-1   20Gi       RWO            Retain           Bound       magedu/zookeeper-datadir-pvc-1                           10d
zookeeper-datadir-pv-2   20Gi       RWO            Retain           Bound       magedu/zookeeper-datadir-pvc-2                           10d
zookeeper-datadir-pv-3   20Gi       RWO            Retain           Bound       magedu/zookeeper-datadir-pvc-3                           10d
root@k8s-master01:~/k8s-data/yaml/magedu/mysql# 

3.3、运行mysql服务

MYSQL CONFIGMAP配置清单

apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql
  namespace: magedu
  labels:
    app: mysql
data:
  master.cnf: |
    # Apply this config only on the master.
    [mysqld]
    log-bin
    log_bin_trust_function_creators=1
    lower_case_table_names=1
  slave.cnf: |
    # Apply this config only on slaves.
    [mysqld]
    super-read-only
    log_bin_trust_function_creators=1

MYSQL POD配置清单

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mysql
  namespace: magedu
spec:
  selector:
    matchLabels:
      app: mysql
  serviceName: mysql
  replicas: 2
  template:
    metadata:
      labels:
        app: mysql
    spec:
      initContainers:
      - name: init-mysql #初始化容器1、基于当前pod name匹配角色是master还是slave，并动态生成相对应的配置文件
        image: harbor.ik8s.cc/magedu/mysql:5.7.36
        command:
        - bash
        - "-c"
        - |
          set -ex
          # Generate mysql server-id from pod ordinal index.
          [[ `hostname` =~ -([0-9]+)$ ]] || exit 1 #匹配hostname的最后一位、最后是一个顺序叠加的整数
          ordinal=${BASH_REMATCH[1]} 
          echo [mysqld] > /mnt/conf.d/server-id.cnf
          # Add an offset to avoid reserved server-id=0 value.
          echo server-id=$((100 + $ordinal)) >> /mnt/conf.d/server-id.cnf
          # Copy appropriate conf.d files from config-map to emptyDir.
          if [[ $ordinal -eq 0 ]]; then #如果是master、则cpmaster配置文件
            cp /mnt/config-map/master.cnf /mnt/conf.d/
          else #否则cp slave配置文件
            cp /mnt/config-map/slave.cnf /mnt/conf.d/
          fi
        volumeMounts:
        - name: conf #临时卷、emptyDir
          mountPath: /mnt/conf.d
        - name: config-map
          mountPath: /mnt/config-map
      - name: clone-mysql #初始化容器2、用于生成mysql配置文件、并从上一个pod完成首次的全量数据clone(slave 3从slave2 clone，而不是每个slave都从master clone实现首次全量同步,但是后期都是与master实现增量同步)
        image: harbor.ik8s.cc/magedu/xtrabackup:1.0 
        command:
        - bash
        - "-c"
        - |
          set -ex
          # Skip the clone if data already exists.
          [[ -d /var/lib/mysql/mysql ]] && exit 0
          # Skip the clone on master (ordinal index 0).
          [[ `hostname` =~ -([0-9]+)$ ]] || exit 1
          ordinal=${BASH_REMATCH[1]}
          [[ $ordinal -eq 0 ]] && exit 0 #如果最后一位是0(master)则退出clone过程
          # Clone data from previous peer.
          ncat --recv-only mysql-$(($ordinal-1)).mysql 3307 | xbstream -x -C /var/lib/mysql #从上一个pod执行clone(binlog),xbstream为解压缩命令
          # Prepare the backup.xue
          xtrabackup --prepare --target-dir=/var/lib/mysql #通过xtrabackup恢复binlog
        volumeMounts:
        - name: data
          mountPath: /var/lib/mysql
          subPath: mysql
        - name: conf
          mountPath: /etc/mysql/conf.d
      containers:
      - name: mysql #业务容器1(mysql主容器)
        image: harbor.ik8s.cc/magedu/mysql:5.7.36
        env:
        - name: MYSQL_ALLOW_EMPTY_PASSWORD
          value: "1"
        ports:
        - name: mysql
          containerPort: 3306
        volumeMounts:
        - name: data #挂载数据目录至/var/lib/mysql
          mountPath: /var/lib/mysql
          subPath: mysql
        - name: conf #配置文件/etc/mysql/conf.d
          mountPath: /etc/mysql/conf.d
        resources: #资源限制
          requests:
            cpu: 500m
            memory: 1Gi
        livenessProbe: #存活探针
          exec:
            command: ["mysqladmin", "ping"]
          initialDelaySeconds: 30
          periodSeconds: 10
          timeoutSeconds: 5
        readinessProbe: #就绪探针
          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
      - name: xtrabackup #业务容器2(xtrabackup),用于后期同步master 的binglog并恢复数据
        image: harbor.ik8s.cc/magedu/xtrabackup:1.0 
        ports:
        - name: xtrabackup
          containerPort: 3307
        command:
        - bash
        - "-c"
        - |
          set -ex
          cd /var/lib/mysql
          # Determine binlog position of cloned data, if any.
          if [[ -f xtrabackup_slave_info ]]; then
            # XtraBackup already generated a partial "CHANGE MASTER TO" query
            # because we're cloning from an existing slave.
            mv xtrabackup_slave_info change_master_to.sql.in
            # Ignore xtrabackup_binlog_info in this case (it's useless).
            rm -f 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 xtrabackup_binlog_info
            echo "CHANGE MASTER TO MASTER_LOG_FILE='${BASH_REMATCH[1]}',\
                  MASTER_LOG_POS=${BASH_REMATCH[2]}" > change_master_to.sql.in #生成CHANGE MASTER命令
          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"
            # In case of container restart, attempt this at-most-once.
            mv change_master_to.sql.in change_master_to.sql.orig 
            #执行CHANGE MASTER操作并启动SLAVE
            mysql -h 127.0.0.1 <<EOF
          $(<change_master_to.sql.orig),
            MASTER_HOST='mysql-0.mysql',
            MASTER_USER='root',
            MASTER_PASSWORD='',
            MASTER_CONNECT_RETRY=10;
          START SLAVE;
          EOF
          fi
          # Start a server to send backups when requested by peers. #监听在3307端口，用于为下一个pod同步全量数据
          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:
        - name: data
          mountPath: /var/lib/mysql
          subPath: mysql
        - name: conf
          mountPath: /etc/mysql/conf.d
        resources:
          requests:
            cpu: 100m
            memory: 100Mi
      volumes:
      - name: conf
        emptyDir: {}
      - name: config-map
        configMap:
          name: mysql
  volumeClaimTemplates:
  - metadata:
      name: data
    spec:
      accessModes: ["ReadWriteOnce"]
      resources:
        requests:
          storage: 10Gi

上述配置清单主要定义两个mysqlPod，其中每个pod中运行4个容器，第一个容器init容器主要目的是通过sts控制器创建pod的名称id来确定挂载master和slave配置；第二个初始化容器主要目的是用于克隆上一个pod的数据，即salve1从master上克隆数据，slave2从slave1克隆数据，以此类推；第三个就是mysql主容器，运行mysql实例；第四个容器主要用于给mysql主容器同步后期的增量数据的；

MYSQL SERVICE配置清单

# Headless service for stable DNS entries of StatefulSet members.
apiVersion: v1
kind: Service
metadata:
  namespace: magedu
  name: mysql
  labels:
    app: mysql
spec:
  ports:
  - name: mysql
    port: 3306
  clusterIP: None
  selector:
    app: mysql
---
# Client service for connecting to any MySQL instance for reads.
# For writes, you must instead connect to the master: mysql-0.mysql.
apiVersion: v1
kind: Service
metadata:
  name: mysql-read
  namespace: magedu
  labels:
    app: mysql
spec:
  ports:
  - name: mysql
    port: 3306
  selector:
    app: mysql

上述配置清单主要创建了两个service，第一个是一个无头service 用户返回后端所有pod端点；第二个service是一个默认clusterip类型service，这两个service都是可以的；

3.3.1、创建mysql pod

root@k8s-master01:~/k8s-data/yaml/magedu/mysql# kubectl apply -f mysql-configmap.yaml -f mysql-services.yaml -f mysql-statefulset.yaml 
configmap/mysql created
service/mysql created
service/mysql-read created
statefulset.apps/mysql created
root@k8s-master01:~/k8s-data/yaml/magedu/mysql# 

3.3.2、验证MySQL Pod状态

root@k8s-master01:~/k8s-data/yaml/magedu/mysql# kubectl get pods -n magedu 
NAME                                             READY   STATUS      RESTARTS       AGE
magedu-nginx-deployment-5589bbf4bc-6gd2w         1/1     Running     8 (113m ago)   11d
magedu-tomcat-app1-deployment-7754c8549c-c7rtb   1/1     Running     4 (114m ago)   11d
magedu-tomcat-app1-deployment-7754c8549c-prglk   1/1     Running     4 (114m ago)   11d
mysql-0                                          2/2     Running     0              47s
mysql-1                                          2/2     Running     0              23s
redis-0                                          1/1     Running     2 (114m ago)   8d
redis-1                                          1/1     Running     2 (114m ago)   8d
redis-2                                          1/1     Running     2 (114m ago)   8d
redis-3                                          1/1     Running     2 (114m ago)   8d
redis-4                                          1/1     Running     2 (114m ago)   8d
redis-5                                          1/1     Running     2 (114m ago)   8d
ubuntu1804                                       0/1     Completed   0              8d
zookeeper1-675c5477cb-vmwwq                      1/1     Running     4 (114m ago)   10d
zookeeper2-759fb6c6f-7jktr                       1/1     Running     4 (114m ago)   10d
zookeeper3-5c78bb5974-vxpbh                      1/1     Running     4 (114m ago)   10d
root@k8s-master01:~/k8s-data/yaml/magedu/mysql# 

修改配置清单pod副本为3，看看对应pod是否能够正常running?

应用配置清单

3.3.3、验证MySQL主从同步是否正常

验证master状态

root@k8s-master01:~# kubectl exec -it mysql-0 -n magedu  bash 
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
Defaulted container "mysql" out of: mysql, xtrabackup, init-mysql (init), clone-mysql (init)
root@mysql-0:/# mysql 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 691
Server version: 5.7.36-log MySQL Community Server (GPL)

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show master status\G
*************************** 1. row ***************************
             File: mysql-0-bin.000003
         Position: 313
     Binlog_Do_DB: 
 Binlog_Ignore_DB: 
Executed_Gtid_Set: 
1 row in set (0.01 sec)

mysql> exit
Bye
root@mysql-0:/# exit
exit
root@k8s-master01:~# 

验证slave状态

root@k8s-master01:~# kubectl exec -it mysql-1 -n magedu  bash  
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
Defaulted container "mysql" out of: mysql, xtrabackup, init-mysql (init), clone-mysql (init)
root@mysql-1:/# mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 708
Server version: 5.7.36 MySQL Community Server (GPL)

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: mysql-0.mysql
                  Master_User: root
                  Master_Port: 3306
                Connect_Retry: 10
              Master_Log_File: mysql-0-bin.000003
          Read_Master_Log_Pos: 313
               Relay_Log_File: mysql-1-relay-bin.000002
                Relay_Log_Pos: 481
        Relay_Master_Log_File: mysql-0-bin.000003
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB: 
          Replicate_Ignore_DB: 
           Replicate_Do_Table: 
       Replicate_Ignore_Table: 
      Replicate_Wild_Do_Table: 
  Replicate_Wild_Ignore_Table: 
                   Last_Errno: 0
                   Last_Error: 
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 313
              Relay_Log_Space: 690
              Until_Condition: None
               Until_Log_File: 
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File: 
           Master_SSL_CA_Path: 
              Master_SSL_Cert: 
            Master_SSL_Cipher: 
               Master_SSL_Key: 
        Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error: 
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 100
                  Master_UUID: 72724f41-0b65-11ee-b561-16065cd6961a
             Master_Info_File: /var/lib/mysql/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: 
                Auto_Position: 0
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
1 row in set (0.00 sec)

mysql> exit 
Bye
root@mysql-1:/# exit
exit
root@k8s-master01:~# kubectl exec -it mysql-2 -n magedu  bash  
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
Defaulted container "mysql" out of: mysql, xtrabackup, init-mysql (init), clone-mysql (init)
root@mysql-2:/# mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 632
Server version: 5.7.36 MySQL Community Server (GPL)

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: mysql-0.mysql
                  Master_User: root
                  Master_Port: 3306
                Connect_Retry: 10
              Master_Log_File: mysql-0-bin.000003
          Read_Master_Log_Pos: 313
               Relay_Log_File: mysql-2-relay-bin.000002
                Relay_Log_Pos: 481
        Relay_Master_Log_File: mysql-0-bin.000003
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB: 
          Replicate_Ignore_DB: 
           Replicate_Do_Table: 
       Replicate_Ignore_Table: 
      Replicate_Wild_Do_Table: 
  Replicate_Wild_Ignore_Table: 
                   Last_Errno: 0
                   Last_Error: 
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 313
              Relay_Log_Space: 690
              Until_Condition: None
               Until_Log_File: 
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File: 
           Master_SSL_CA_Path: 
              Master_SSL_Cert: 
            Master_SSL_Cipher: 
               Master_SSL_Key: 
        Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error: 
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 100
                  Master_UUID: 72724f41-0b65-11ee-b561-16065cd6961a
             Master_Info_File: /var/lib/mysql/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: 
                Auto_Position: 0
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
1 row in set (0.00 sec)

mysql> exit
Bye
root@mysql-2:/# exit
exit
root@k8s-master01:~#

能够在slave上看到IO和SQL线程正常running，说明slave状态没有问题；

进入mysql-0创建数据库

root@k8s-master01:~/k8s-data/yaml/magedu/mysql# kubectl exec -it mysql-0 -n magedu  bash
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
Defaulted container "mysql" out of: mysql, xtrabackup, init-mysql (init), clone-mysql (init)
root@mysql-0:/# mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 355
Server version: 5.7.36-log MySQL Community Server (GPL)

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show databases;
+------------------------+
| Database               |
+------------------------+
| information_schema     |
| mysql                  |
| performance_schema     |
| sys                    |
| xtrabackup_backupfiles |
+------------------------+
5 rows in set (0.02 sec)

mysql> create database mydb;
Query OK, 1 row affected (0.00 sec)

mysql> show databases;
+------------------------+
| Database               |
+------------------------+
| information_schema     |
| mydb                   |
| mysql                  |
| performance_schema     |
| sys                    |
| xtrabackup_backupfiles |
+------------------------+
6 rows in set (0.00 sec)

mysql> 

在slave pod中验证数据是否同步？

root@k8s-master01:~/k8s-data/yaml/magedu/mysql# kubectl exec -it mysql-1 -n magedu  bash 
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
Defaulted container "mysql" out of: mysql, xtrabackup, init-mysql (init), clone-mysql (init)
root@mysql-1:/# mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 437
Server version: 5.7.36 MySQL Community Server (GPL)

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show databases;
+------------------------+
| Database               |
+------------------------+
| information_schema     |
| mydb                   |
| mysql                  |
| performance_schema     |
| sys                    |
| xtrabackup_backupfiles |
+------------------------+
6 rows in set (0.01 sec)

mysql> exit
Bye
root@mysql-1:/# exit
exit
root@k8s-master01:~/k8s-data/yaml/magedu/mysql# kubectl exec -it mysql-2 -n magedu  bash  
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
Defaulted container "mysql" out of: mysql, xtrabackup, init-mysql (init), clone-mysql (init)
root@mysql-2:/# mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 361
Server version: 5.7.36 MySQL Community Server (GPL)

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show databases;
+------------------------+
| Database               |
+------------------------+
| information_schema     |
| mydb                   |
| mysql                  |
| performance_schema     |
| sys                    |
| xtrabackup_backupfiles |
+------------------------+
6 rows in set (0.02 sec)

mysql> exit
Bye
root@mysql-2:/# exit
exit
root@k8s-master01:~/k8s-data/yaml/magedu/mysql#

能够通过上述在主库创建数据库，从库能够正常同步，则说明mysql主从同步没有问题；

3.3.4、mysql⾼可⽤测试

3.3.4.1、删除master pod验证mysql高可用性

进入master，验证master数据是否丢失？

能够看到master数据并未丢失，这是因为该数据存放至远端nfs存储之上；

3.3.4.2、删除slave pod验证mysql高可用性

root@k8s-master01:~# kubectl get pods -n magedu 
NAME                                             READY   STATUS      RESTARTS       AGE
magedu-nginx-deployment-5589bbf4bc-6gd2w         1/1     Running     8 (143m ago)   11d
magedu-tomcat-app1-deployment-7754c8549c-c7rtb   1/1     Running     4 (143m ago)   11d
magedu-tomcat-app1-deployment-7754c8549c-prglk   1/1     Running     4 (143m ago)   11d
mysql-0                                          2/2     Running     0              3m6s
mysql-1                                          2/2     Running     0              29m
mysql-2                                          2/2     Running     0              27m
redis-0                                          1/1     Running     2 (143m ago)   8d
redis-1                                          1/1     Running     2 (143m ago)   8d
redis-2                                          1/1     Running     2 (143m ago)   8d
redis-3                                          1/1     Running     2 (143m ago)   8d
redis-4                                          1/1     Running     2 (143m ago)   8d
redis-5                                          1/1     Running     2 (143m ago)   8d
ubuntu1804                                       0/1     Completed   0              8d
zookeeper1-675c5477cb-vmwwq                      1/1     Running     4 (143m ago)   10d
zookeeper2-759fb6c6f-7jktr                       1/1     Running     4 (143m ago)   10d
zookeeper3-5c78bb5974-vxpbh                      1/1     Running     4 (143m ago)   10d
root@k8s-master01:~# kubectl delete pods mysql-1 -n magedu 
pod "mysql-1" deleted
root@k8s-master01:~# kubectl get pods -n magedu 
NAME                                             READY   STATUS      RESTARTS       AGE
magedu-nginx-deployment-5589bbf4bc-6gd2w         1/1     Running     8 (144m ago)   11d
magedu-tomcat-app1-deployment-7754c8549c-c7rtb   1/1     Running     4 (145m ago)   11d
magedu-tomcat-app1-deployment-7754c8549c-prglk   1/1     Running     4 (145m ago)   11d
mysql-0                                          2/2     Running     0              4m55s
mysql-1                                          2/2     Running     0              55s
mysql-2                                          2/2     Running     0              28m
redis-0                                          1/1     Running     2 (145m ago)   8d
redis-1                                          1/1     Running     2 (145m ago)   8d
redis-2                                          1/1     Running     2 (145m ago)   8d
redis-3                                          1/1     Running     2 (145m ago)   8d
redis-4                                          1/1     Running     2 (145m ago)   8d
redis-5                                          1/1     Running     2 (145m ago)   8d
ubuntu1804                                       0/1     Completed   0              8d
zookeeper1-675c5477cb-vmwwq                      1/1     Running     4 (145m ago)   10d
zookeeper2-759fb6c6f-7jktr                       1/1     Running     4 (145m ago)   10d
zookeeper3-5c78bb5974-vxpbh                      1/1     Running     4 (145m ago)   10d
root@k8s-master01:~# 

进入slave验证数据