k8s配置mysql主从复制

一、概述

本文档采用kubernetes8.5+mysql5.7+NFS数据持久化，搭建mysql的主从服务。

二、准备mysql主从镜像

dockerfile、docker-entrypoint.sh 文件下载地址如下
https://github.com/docker-library/mysql/tree/master/5.7
由于我们要配置mysql主从，所以需要对dockerfile、docker-entrypoint.sh 文件做一点的修改，主要是在mysql主从配置部分。

准备master的镜像

将Dockerfile, docker-entrypoint.sh复制一份用于build master镜像文件。
在Dockerfile中添加如下内容，将mysql master的server-id设置为1
RUN sed -i '/\[mysqld\]/a server-id=1\nlog-bin' /etc/mysql/mysql.conf.d/mysqld.cnf

在docker-entrypoint.sh中添加如下内容，创建一个复制用户并赋权限，刷新系统权限表
```
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 ;' | "${mysql[@]}"
```
准备slave的镜像
将Dockerfile, docker-entrypoint.sh复制一份用于build slave镜像文件。
在Dockerfile中添加如下内容，将mysql slave的server-id设置为一个随机数
RUN RAND="$(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中添加如下内容，配置连接master主机的host、user、password等参数，并启动复制进程。
```
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[@]}"
```

使用Dockerfile创建镜像
创建镜像前需要确保docker-entrypoint.sh有可执行权限
chmod +x docker-entrypoint.sh

 # cd /root/mysql/master/   # master Dockerfile所在目录
 # docker build -t 192.168.1.98/library/mysql-master:0.1        #IP地址为harbor仓库地址
 # cd /root/mysql/slave     # slave Dockerfile所在目录
 # docker build -t 192.168.1.98/library/mysql-slabe:0.1
 # docker push 192.168.1.98/library/mysql-master:0.1        # 上传镜像到仓库中
 # docker push 192.168.1.98/library/mysql-slave:0.1

三、创建pv和pvc

在nfs服务器创建目录
编辑/etc/exports目录，添加如下两行，确保本地有这两个目录。
```
/var/hitsm/mysql_master *(rw,no_root_squash,no_all_squash,sync)
/var/hitsm/mysql_slave *(rw,no_root_squash,no_all_squash,sync)
```
使配置生效
exportfs -r

通过yml文件创建两组pv 和 pvc


# cat nfs-pv-master.yaml

apiVersion: v1
kind: PersistentVolume
metadata:
 name: pv-nfs-mysql-master
spec:
 capacity:
   storage: 5Gi 
 accessModes:
 - ReadWriteOnce
 nfs: 
   path: /var/hitsm/mysql-master
   server: 192.168.1.98
 persistentVolumeReclaimPolicy: Recycle 

# cat nfs-pvc-master.yaml

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
 name: pv-nfs-mysql-master
spec:
 accessModes:
   - ReadWriteOnce
 resources:
   requests:
     storage: 5Gi

# cat nfs-pv-slave.yaml 

apiVersion: v1
kind: PersistentVolume
metadata:
 name: pv-nfs-mysql-slave
spec:
 capacity:
   storage: 6Gi 
 accessModes:
 - ReadWriteOnce
 nfs: 
   path: /var/hitsm/mysql_slave
   server: 192.168.1.98
 persistentVolumeReclaimPolicy: Recycle 


# cat nfs-pvc-slave.yaml 

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
 name: pv-nfs-mysql-slave
spec:
 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

这里写图片描述

四、部署mysql

mysql master部署


# cat mysql-master-rc.yaml 

apiVersion: v1
kind: ReplicationController
metadata:
name: mysql-master
labels:
 name: mysql-master
spec:
 replicas: 1
 selector:
  name: mysql-master
 template:
  metadata:
   labels:
    name: mysql-master
  spec:
   containers:
   - name: mysql-master
     image: 192.168.1.98/library/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: v1
kind: Service
metadata:
 name: mysql-master
 labels:
  name: mysql-master
spec:
 type: NodePort
 ports:
 - port: 3306
   targetPort: 3306
   name: http
   nodePort: 30066
 selector:
   name: mysql-master


# kubectl create -f mysql-master-rc.yaml -n mysql


# kubectl create -f mysql-master-svc.yaml -n mysql

这里写图片描述

mysql slave部署


# cat mysql-slave-rc.yaml 

apiVersion: v1
kind: ReplicationController
metadata:
name: mysql-slave
labels:
 name: mysql-slave
spec:
 replicas: 1
 selector:
  name: mysql-slave
 template:
  metadata:
   labels:
    name: mysql-slave
  spec:
   containers:
   - name: mysql-slave
     image: 192.168.1.98/library/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: v1
kind: Service
metadata:
 name: mysql-slave
 labels:
  name: mysql-slave
spec:
 type: NodePort
 ports:
 - port: 3306
   targetPort: 3306
   name: http
   nodePort: 30067
 selector:
   name: mysql-slave


# kubectl create -f mysql-slave-rc.yaml -n mysql


# kubectl create -f mysql-slave-svc.yaml -n mysql

五、测试

登录到slave mysql，使用 “show slave status\G” 命令查看，出现如下，表示主从连接成功，如果报错，也可以通过这个页面看出。

在master mysql中创建数据库、表、插入数据等，来验证主从是否配置成功。

在master数据库执行

mysql>create database hitsm;
mysql>usehitsm;
mysql>
CREATE TABLE databasechangeloglock (
ID int(11) NOT NULL,
LOCKED bit(1) NOT NULL,
LOCKGRANTED datetime DEFAULT NULL,
LOCKEDBY varchar(255)
DEFAULT NULL) ENGINE=InnoDB DEFAULT CHARSET=utf8 ROW_FORMAT=DYNAMIC;
mysql>
INSERT INTO databasechangeloglock (ID, LOCKED,LOCKGRANTED, LOCKEDBY) VALUES (1, b'0', NULL, NULL);