在kubernetes叢集中部署mysql主從

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本文介紹在kubernetes環境中部署mysql主從叢集，資料持久化採用nfs。

一、環境介紹
Mysql版本：5.7

Mysql master節點：
主機名稱：vm1
IP地址：192.168.115.5/24

Mysql slave節點：
主機名稱：vm2
IP地址：192.168.115.6/24

NFS節點：
主機名稱：vm2
IP地址：192.168.115.6/24
共用目錄：/home/mysql_master、/home/mysql_slave

二、準備mysql主從的鏡像環境
dockerfile、docker-entrypoint.sh 檔案如下
https://github.com/docker-library/mysql/tree/master/5.7
由於我們要配置mysql主從，所以需要對dockerfile、docker-entrypoint.sh 檔案做一點的修改，主要是在mysql主從配置部分。

準備master的鏡像
將Dockerfile, docker-entrypoint.sh複製一份用於build master鏡像檔案。
在Dockerfile中添加如下內容，將mysql master的server-id設定為1

RUN sed -i ‘/\[mysqld\]/a server-id=1\nlog-bin‘ /etc/mysql/mysql.conf.d/mysqld.cnf

在docker-entrypoint.sh中添加如下內容，建立一個複製使用者並賦許可權，重新整理系統許可權表

echo "CREATE USER ‘$MYSQL_REPLICATION_USER‘@‘%‘ IDENTIFIED BY ‘$MYSQL_REPLICATION_PASSWORD‘ ;" | "${mysql[@]}" echo "GRANT REPLICATION SLAVE ON *.* TO ‘$MYSQL_REPLICATION_USER‘@‘%‘ IDENTIFIED BY ‘$MYSQL_REPLICATION_PASSWORD‘ ;" | "${mysql[@]}" echo ‘FLUSH PRIVILEGES ;‘ | "${mysql[@]}"

準備slave的鏡像
將Dockerfile, docker-entrypoint.sh複製一份用於build slave鏡像檔案。
在Dockerfile中添加如下內容，將mysql slave的server-id設定為一個隨機數

RUN RAND="$(date +%s | rev | cut -c 1-2)$(echo ${RANDOM})" && sed -i ‘/\[mysqld\]/a server-id=‘$RAND‘\nlog-bin‘ /etc/mysql/mysql.conf.d/mysqld.cnf

在docker-entrypoint.sh中添加如下內容，配置串連master主機的host、user、password等參數，並啟動複製進程。

echo "STOP SLAVE;" | "${mysql[@]}" echo "CHANGE MASTER TO master_host=‘$MYSQL_MASTER_SERVICE_HOST‘, master_user=‘$MYSQL_REPLICATION_USER‘, master_password=‘$MYSQL_REPLICATION_PASSWORD‘ ;" | "${mysql[@]}" echo "START SLAVE;" | "${mysql[@]}"

三、開始使用修改好的dockerfile建立mysql master和slave鏡像

# cd /root/kubernetes/lnmp/mysql/Dockerfiles/Master# docker build -t registry.fjhb.cn/mysql-master:0.1 .# cd /root/kubernetes/lnmp/mysql/Dockerfiles/Slave# docker build -t registry.fjhb.cn/mysql-slave:0.1 .# docker push registry.fjhb.cn/mysql-master:0.1# docker push registry.fjhb.cn/mysql-slave:0.1

四、建立pv和pvc，用於mysql主從儲存持久化資料
在nfs伺服器上把目錄建立出來

# cd /home/# mkdir mysql_master mysql_slave

通過yaml檔案建立出兩組pv和pvc

# cd /root/kubernetes/lnmp/mysql/Storage# cat nfs-pv-master.yamlapiVersion: v1kind: PersistentVolumemetadata:  name: pv-nfs-mysql-masterspec:  capacity:    storage: 5Gi   accessModes:  - ReadWriteOnce  nfs:     path: /home/mysql_master    server: 192.168.115.6  persistentVolumeReclaimPolicy: Recycle # cat nfs-pvc-master.yamlkind: PersistentVolumeClaimapiVersion: v1metadata:  name: pv-nfs-mysql-masterspec:  accessModes:    - ReadWriteOnce  resources:    requests:      storage: 5Gi# cat nfs-pv-slave.yaml apiVersion: v1kind: PersistentVolumemetadata:  name: pv-nfs-mysql-slavespec:  capacity:    storage: 6Gi   accessModes:  - ReadWriteOnce  nfs:     path: /home/mysql_slave    server: 192.168.115.6  persistentVolumeReclaimPolicy: Recycle # cat nfs-pvc-slave.yaml kind: PersistentVolumeClaimapiVersion: v1metadata:  name: pv-nfs-mysql-slavespec:  accessModes:    - ReadWriteOnce  resources:    requests:      storage: 6Gi# kubectl create -f nfs-pv-master.yaml# kubectl create -f nfs-pvc-master.yaml# kubectl create -f nfs-pv-slave.yaml # kubectl create -f nfs-pvc-slave.yaml 

五、根據yaml檔案建立mysql master ReplicationController和services

# cat mysql-master-rc.yaml apiVersion: v1kind: ReplicationControllermetadata: name: mysql-master labels:  name: mysql-masterspec:  replicas: 1  selector:   name: mysql-master  template:   metadata:    labels:     name: mysql-master   spec:    containers:    - name: mysql-master      image: registry.fjhb.cn/mysql-master:0.1      volumeMounts:        - mountPath: /var/lib/mysql          name: mysql-master-data      ports:      - containerPort: 3306      env:      - name: MYSQL_ROOT_PASSWORD        value: "12345678"      - name: MYSQL_REPLICATION_USER        value: "repl"      - name: MYSQL_REPLICAITON_PASSWORD        value: "12345678"    volumes:     - name: mysql-master-data       persistentVolumeClaim:        claimName: pv-nfs-mysql-master# cat mysql-master-svc.yaml apiVersion: v1kind: Servicemetadata:  name: mysql-master  labels:   name: mysql-masterspec:  type: NodePort  ports:  - port: 3306    targetPort: 3306    name: http    nodePort: 30066  selector:    name: mysql-master# kubectl create -f mysql-master-rc.yaml # kubectl create -f mysql-master-svc.yaml

使用mysql用戶端串連master測試

六、根據yaml檔案建立mysql slave ReplicationController和services

# cat mysql-slave-rc.yaml apiVersion: v1kind: ReplicationControllermetadata: name: mysql-slave labels:  name: mysql-slavespec:  replicas: 1  selector:   name: mysql-slave  template:   metadata:    labels:     name: mysql-slave   spec:    containers:    - name: mysql-slave      image: registry.fjhb.cn/mysql-slave:0.1      volumeMounts:        - mountPath: /var/lib/mysql          name: mysql-slave-data      ports:      - containerPort: 3306      env:      - name: MYSQL_ROOT_PASSWORD        value: "12345678"      - name: MYSQL_REPLICATION_USER        value: "repl"      - name: MYSQL_REPLICAITON_PASSWORD        value: "12345678"    volumes:     - name: mysql-slave-data       persistentVolumeClaim:        claimName: pv-nfs-mysql-slave# cat mysql-slave-svc.yaml apiVersion: v1kind: Servicemetadata:  name: mysql-slave  labels:   name: mysql-slavespec:  type: NodePort  ports:  - port: 3306    targetPort: 3306    name: http    nodePort: 30067  selector:    name: mysql-slave# kubectl create -f mysql-slave-rc.yaml # kubectl create -f mysql-slave-svc.yaml 

七、測試與排錯
通過mysql命令列串連slave查看複製的狀態，發現狀態是connecting

使用slave 容器串連master,發現使用root帳號可以正常串連，而使用repl帳號無法正常串連，提示access deny

修改master上的repl使用者密碼

mysql> alter user [email protected]‘%‘ identified by "12345678";Query OK, 0 rows affected (0.00 sec)mysql> flush privileges;Query OK, 0 rows affected (0.00 sec)

完成上述修改後在slave上進行驗證一下，repl帳號可以正常串連

在slave上進行change master操作，因為建立鏡像的時候並未配置GTID參數，所以這裡不能使用MASTER_AUTO_POSITION=1參數，如果要開啟，需要去修改Dockerfile，重建鏡像。

mysql> stop slave;mysql> set global sql_slave_skip_counter=1;CHANGE MASTER TO MASTER_HOST=‘mysql-master‘, MASTER_USER=‘repl‘, MASTER_PASSWORD=‘12345678‘;mysql> start slave;

參考文檔：
https://www.jianshu.com/p/509b65e9a4f5

在kubernetes叢集中部署mysql主從