Kubernetes 实战-基于StatefulSet控制器运行MySQL一主多从（三）

Mysql conf

cat mysql-configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql
  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

kubectl apply -f mysql-configmap.yaml

Mysql service

[root@xianchaomaster1 mysql]# cat mysql-services.yaml
# Headless service for stable DNS entries of StatefulSet members.
apiVersion: v1
kind: Service
metadata:
  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
  labels:
    app: mysql
spec:
  ports:
  - name: mysql
    port: 3306
  selector:
    app: mysql
    
[root@xianchaomaster1 mysql]# kubectl apply -f mysql-services.yaml

Mysql pv

[root@xianchaomaster1 pv]# mkdir /data/k8sdata/xks/mysql-datadir-1
[root@xianchaomaster1 pv]# mkdir /data/k8sdata/xks/mysql-datadir-2
[root@xianchaomaster1 pv]# mkdir /data/k8sdata/xks/mysql-datadir-3
[root@xianchaomaster1 pv]# mkdir /data/k8sdata/xks/mysql-datadir-4
[root@xianchaomaster1 pv]# mkdir /data/k8sdata/xks/mysql-datadir-5
[root@xianchaomaster1 pv]# mkdir /data/k8sdata/xks/mysql-datadir-6

[root@xianchaomaster1 pv]# exportfs -arv

[root@xianchaomaster1 pv]# cat mysql-persistentvolume.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-datadir-1
spec:
  capacity:
    storage: 50Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    path: /data/k8sdata/xks/mysql-datadir-1
    server: 192.168.40.180
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-datadir-2
spec:
  capacity:
    storage: 50Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    path: /data/k8sdata/xks/mysql-datadir-2
    server: 192.168.40.180
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-datadir-3
spec:
  capacity:
    storage: 50Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    path: /data/k8sdata/xks/mysql-datadir-3
    server: 192.168.40.180
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-datadir-4
spec:
  capacity:
    storage: 50Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    path: /data/k8sdata/xks/mysql-datadir-4
    server: 192.168.40.180
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-datadir-5
spec:
  capacity:
    storage: 50Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    path: /data/k8sdata/xks/mysql-datadir-5
    server: 192.168.40.180

---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-datadir-6
spec:
  capacity:
    storage: 50Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    path: /data/k8sdata/xks/mysql-datadir-6
    server: 192.168.40.180
    
[root@xianchaomaster1 pv]# kubectl apply -f mysql-persistentvolume.yaml

mysql  yaml

[root@xianchaomaster1 mysql]# cat mysql-statefulset.yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mysql
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.magedu.net/baseimages/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 [[ $ordinal -eq 0 ]]; then #如果是master、则cpmaster配置文件
            cp /mnt/config-map/master.cnf /mnt/conf.d/
          else #否则cp slave配置文件
            cp /mnt/config-map/slave.cnf /mnt/conf.d/
          fi
        volumeMounts:
        - name: conf #临时卷、emptyDir
          mountPath: /mnt/conf.d
        - name: config-map
          mountPath: /mnt/config-map
      - name: clone-mysql #初始化容器2、用于生成mysql配置文件、并从上一个pod完成首次的全量数据clone(slave 3从slave2 clone，而不是每个slave都从master clone实现首次全量同步,但是后期都是与master实现增量同步)
        image: harbor.magedu.net/baseimages/xtrabackup:1.0
        command:
        - bash
        - "-c"
        - |
          set -ex
          # Skip the clone if data already exists.
          [[ -d /var/lib/mysql/mysql ]] && exit 0
          # Skip the clone on master (ordinal index 0).
          [[ `hostname` =~ -([0-9]+)$ ]] || 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.magedu.net/baseimages/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.magedu.net/baseimages/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
          
[root@xianchaomaster1 pv]# kubectl apply -f mysql-statefulset.yaml

验证 

[root@xianchaomaster1 pv]# kubectl run test --image=registry.cn-hangzhou.aliyuncs.com/public_ns/mysql:5.7 -it -- bash
If you don't see a command prompt, try pressing enter.
root@test:/# mysql -h mysql-0.mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 746
Server version: 5.7.36-log MySQL Community Server (GPL)

Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.

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> create database redhat;
Query OK, 1 row affected (0.01 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| redhat             |
| sys                |
+--------------------+
5 rows in set (0.01 sec)

mysql>