MYSQL高可用方案主要分爲兩大類,一類是前置管理,一類是後置管理。
前置管理的思想是利用各種前置管理工具,動態切換或者分發請求到不同的實例並切換master,如keepalived、MHA、packmaker+Corosync、MySQLProxy等,一般通過暴露VIP將整個MYQL集羣隱藏起來,其中Proxy主要用以讀寫分離。後置管理則是利用共享存儲的思想,如NDB方案。由於我們的用戶尚不足百萬,所以一開始的計劃是選擇最簡單的前置管理模式-雙主+keepalived方案,後來因爲阿里雲停用了VIP服務,於是購買了其提供的負載均衡SLB服務(替代keepalived使用),最終完成了雙主+VIP的搭建。不管怎樣,keepalived的思想還是比較經典的,所以也做了簡單記錄。
Part1 mysql bin 方式安裝和配置
#查詢已經存在的mysql並刪除
rpm -qa |grep mysql
rpm -qa |grep mariadb
#刪除已經存在的mysql
rpm -e --nodeps mariadbxxxx
rpm -e --nodeps mysqlxxxx
#下載解壓並copy到/usr/local/mysql
#創建mysql數據日誌目錄
mkdir -p /data/mysql/data
mkdir -p /data/mysql/log
mkdir -p /data/mysql/bak
#初始化my.cnf
[mysql]
default-character-set=utf8
[mysqld]
character_set_server=utf8
default-storage-engine=INNODB
datadir=/data/mysql/data
#socket=/data/mysql/data/mysql.sock
port=3306
symbolic-links=0
log-error=/data/mysql/log/mysqld.log
pid-file=/data/mysql/mysqld.pid
###將support-files的mysql.server copy 到etc/init.d/以開機啓動
cd /usr/local/mysql/support-files/
cp mysql.server /etc/init.d/mysql
#修改mysql默認配置
vim /etc/init.d/mysql
basedir=/usr/local/mysql
datadir=/data/mysql/data
#創建mysql系統用戶並授權到mysql啓動
groupadd mysql
useradd -r -g mysql mysql
passwd mysql
mysqlpwd
chown -R mysql:mysql /usr/local/mysql/
chown -R mysql:mysql /data/mysql/
#將mysqlbin目錄添加到環境變量
echo 'export PATH=/usr/local/mysql/bin:$PATH' >> /etc/profile
source /etc/profile
#初始化mysql數據庫
yum install libaio-devel.x86_64
mysqld --initialize --user=mysql --basedir=/usr/local/mysql --datadir=/data/mysql/data
#獲取初始密碼
tail -f /data/mysql/log/mysql.log
[Note] A temporary password is generated for root@localhost: im>wqfae&7tY
#給數據庫加密
mysql_ssl_rsa_setup --datadir=/data/mysql/data
chown -R mysql:mysql /data/mysql/
##設置開機自動重啓
chkconfig --add mysql
chkconfig mysql on
##查看、停止、重啓mysql
systemclt status mysql.service
systemctl start mysql.service
systemctl stop mysql.service
systemctl restart mysql.service
#啓動mysql服務systemctl start mysql.service
#使用初始密碼登錄mysql -uroot -p --socket=/data/mysql/data/mysql.sock
#設置新密碼,授權root用戶訪問
set password=password('*******');
grant all privileges on *.* to root@'%' identified by '('*******');';
flush privileges;
Part2 mysql高可用配置 - keepalived
1. 配置master1和master2 binlog
#master1配置
[mysqld]
log-bin=mysql-bin
server-id=70
gtid_mode = on
enforce_gtid_consistency = 1
log_slave_updates=1
#binlog-ignore=mysql
#binlog-ignore=information_schema
#replicate-do-db=platform88
#master2配置
[mysqld]
log-bin=mysql-bin
server-id=71
gtid_mode = on
enforce_gtid_consistency = 1
log_slave_updates=1
#binlog-ignore=mysql
#binlog-ignore=information_schema
#replicate-do-db=platform88
#read_only=1
###備註:手動切換主庫
mysql> stop slave;
#千萬不要執行 reset master,否則會從最先的GTID上開始執行。
mysql> change master to master_host='127.0.0.1',master_user='rep',master_password='rep',master_port=3307,master_auto_position=1; #指定到另一個比較接近主的從上。
mysql> start slave;
2. 創建可互相訪問的用戶
#master1配置
CREATE USER 'ms_repl_usr'@'172.26.27.71' IDENTIFIED BY 'ms_repl_pwd';
GRANT REPLICATION SLAVE ON *.* TO 'ms_repl_usr'@'172.26.27.71';
FLUSH PRIVILEGES;
#master2配置
CREATE USER 'ms_repl_usr'@'172.26.27.70' IDENTIFIED BY 'ms_repl_pwd';
GRANT REPLICATION SLAVE ON *.* TO 'ms_repl_usr'@'172.26.27.70';
FLUSH PRIVILEGES;
查看binlog及位移show master status \G
#master1配置
CHANGE MASTER TO
MASTER_HOST='172.26.27.71',
MASTER_PORT=30468,
MASTER_USER='ms_repl_usr',
MASTER_PASSWORD='ms_repl_pwd',
MASTER_LOG_FILE='mysql-bin.000002',
MASTER_LOG_POS=1459;
或者:change master to master_host='172.26.27.71',master_user='ms_repl_usr',master_password='ms_repl_pwd', master_auto_position=1;
#master2配置
CHANGE MASTER TO
MASTER_HOST='172.26.27.70',
MASTER_PORT=30468,
MASTER_USER='ms_repl_usr',
MASTER_PASSWORD='ms_repl_pwd',
MASTER_LOG_FILE='mysql-bin.000002',
MASTER_LOG_POS=2086;
或者:change master to master_host='172.26.27.70'',master_user='ms_repl_usr',master_password='ms_repl_pwd', master_auto_position=1;
#分別重啓master1和master2
查看 salve statusshow slave status \G
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
3. keepalived 配置
keepalived主要用檢測對方服務的狀態,並通過關閉或者重啓自身服務達到切換VIP優先級的效果。keepalived可以監控4層或者7層網絡,4層通過配置虛擬服務實現,本例子中使用7層監控。
#master1 配置
vrrp_script chk_mysql {
script "/etc/keepalived/check_mysql.sh"
interval 30 #設置檢查間隔時長,可根據自己的需求自行設定
}
vrrp_instance VI_1 {
state BACKUP #通過下面的priority來區分MASTER和BACKUP,也只有如此,底下的nopreempt纔有效
interface eth0
virtual_router_id 51
priority 100
advert_int 1
nopreempt #防止切換到從庫後,主keepalived恢復後自動切換回主庫
authentication {
auth_type PASS
auth_pass 88gongxiang
}
track_script {
chk_mysql
}
virtual_ipaddress {
192.168.72.109
}
}
#master2配置
! Configuration File for keepalived
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 51
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass 88gongxiang
}
notify_master /etc/keepalived/notify_master_mysql.sh #此條指令告訴keepalived發現自己轉爲MASTER後執行的腳本
virtual_ipaddress {
192.168.72.109
}
}
#check_mysql.sh主要用來監聽或者鏈接mysql實例,如果發現mysql無法連接,則直接重啓keepalived,或者停止keepalived,讓虛擬IP漂移到另一臺服務器上。這裏以監聽端口爲例:
#!/bin/bash
#This scripts is check for Mysql Slave status
echo 'testing...'
counter=`netstat -luntp|grep 3306|wc -l`
echo 'after counting...'
if [ "$counter" -eq 0 ];
then
echo "3306 is down..."
systemctl stop keepalived
else
echo '3306 is working..'
fi
check腳本中經常遇到的一個問題是,命令需要用全路徑,如mysql登錄,/usr/local/mysql/bin/mysql -uroot -pxxxx --port 3306
修改keepalived的日誌輸出,默認輸出在/var/log/message。從keepalived的日誌中可以看到,master切換的過程。
vim /etc/rsyslog.conf
keepalived -S 0
local0.* /var/log/keepalived.log
- 阿里雲SLB配置實現keepalived效果
#通過負載均衡管理界面創建主備服務器組
#添加雙主實例
這樣就完成了阿里雲雙主的搭建,從這個結構延伸開來,可以分別爲兩個主節點添加slave節點,行程4或者6節點結構。如果需要讀寫分離,提高資源的利用率,可以通過前置mysqlproxy來將讀寫分開。