linux运维、架构之路-MySQL多实例

一、MySQL多实例介绍

           一台服务器上开启多个不同的服务端口（3306，3307,3308），运行多个MySQL服务进程，共用一套MySQL安装程序,多实例MySQL在逻辑上看是各自独立的

1、多实例主从复制原理图

2、优点

①有效利用服务器资源
②节约服务器资源
③资源互相抢占问题，其中一个实例并发很高或者慢查询，其它实例也受影响

3、应用场景

①公司资金紧缺
②并发访问不是特别大的业务
③门户网站应用MySQL多实例场景，一般是从库

4、MySQL多实例常见配置方案

①多配置文件、多启动程序的方案（常用）
②单一配置文件、单一启动程序多实例方案（一个配置文件，不好管理，耦合度太高，）

二、MySQL多实例部署

1、环境

[root@MySQL ~]# cat /etc/redhat-release 
CentOS release 6.9 (Final)
[root@MySQL ~]# uname -r
2.6.32-696.el6.x86_64
[root@MySQL ~]# hostname -I
172.19.5.54 172.16.1.54

2、安装MySQL

useradd -s /sbin/nologin -M mysql
cd /server/tools
tar xf mysql-5.6.36-linux-glibc2.5-x86_64.tar.gz
mv mysql-5.6.36-linux-glibc2.5-x86_64 /application/mysql-5.6.36
ln -s /application/mysql-5.6.36/ /application/mysql
chown -R mysql.mysql /application/mysql

3、配置多实例启动命令和配置文件目录

mkdir -p /data/{3306,3307}/data

4、unzip data.zip 在/下直接解压覆盖/data目录(注：data.zip是打包好的多实例配置文件、数据、启动命令)

[root@MySQL data]# tree 
.
├── 3306
│    ├── data         #3306实例数据文件目录
│    ├── my.cnf       #3306实例配置文件
│    └── mysql        #3306实例启动命令
└── 3307
    ├── data          #3307实例数据文件目录
    ├── my.cnf        #3307实例配置文件
    └── mysql         #3307实例启动命令

5、授权mysql用户管理/data目录

chown -R mysql.mysql /data

6、授权mysql命令执行权限

find /data -type f -name "mysql"|xargs chmod +x

7、配置mysql命令启动环境变量

方法一：
ln -s /application/mysql/bin/* /usr/local/sbin/ 
方法二：
echo 'export PATH=/application/mysql/bin:$PATH' >>/etc/profile
source /etc/profile

8、初始化多实例数据库

cd /application/mysql/scripts/
./mysql_install_db --basedir=/application/mysql/ --datadir=/data/3306/data/ --user=mysql #初始化数据库3306
./mysql_install_db --basedir=/application/mysql/ --datadir=/data/3307/data/ --user=mysql #初始化数据库3307

9、MySQL多实例服务启动

#启动服务
/data/3306/mysql start
/data/3307/mysql start
[root@MySQL data]# netstat -lntup|grep 330
tcp        0      0 :::3306                     :::*                        LISTEN      3848/mysqld         
tcp        0      0 :::3307                     :::*                        LISTEN      4885/mysqld

10、MySQL多实例设置密码及登录

#设置密码：
mysqladmin -uroot password 123456 -S /data/3306/mysql.sock
mysqladmin -uroot password 123456 -S /data/3307/mysql.sock
#登录数据库，指定sock
mysql -uroot -p123456 -S /data/3306/mysql.sock
mysql -uroot -p123456 -S /data/3307/mysql.sock

三、MySQL多实例配置文件

/data/3306/my.cnf [client] port            = 3306 socket          = /data/3306/mysql.sock [mysqld] port            = 3306 socket          = /data/3306/mysql.sock datadir         = /data/3306/data open_files_limit    = 1024 back_log = 600 max_connections = 800 max_connect_errors = 3000 table_open_cache = 512 external-locking = FALSE max_allowed_packet =8M sort_buffer_size = 1M join_buffer_size = 1M thread_cache_size = 100 thread_concurrency = 2 query_cache_size = 2M query_cache_limit = 1M query_cache_min_res_unit = 2k thread_stack = 192K tmp_table_size = 2M max_heap_table_size = 2M long_query_time = 1 pid-file = /data/3306/mysql.pid log-bin = /data/3306/mysql-bin relay-log = /data/3306/relay-bin relay-log-info-file = /data/3306/relay-log.info binlog_cache_size = 1M max_binlog_cache_size = 1M max_binlog_size = 2M expire_logs_days = 7 key_buffer_size = 16M read_buffer_size = 1M read_rnd_buffer_size = 1M bulk_insert_buffer_size = 1M lower_case_table_names = 1 skip-name-resolve slave-skip-errors = 1032,1062 replicate-ignore-db=mysql server-id = 4

/data/3307/my.cnf [client] port            = 3307 socket          = /data/3307/mysql.sock [mysqld] port            = 3307 socket          = /data/3307/mysql.sock datadir         = /data/3307/data open_files_limit    = 1024 back_log = 600 max_connections = 800 max_connect_errors = 3000 table_open_cache = 512 external-locking = FALSE max_allowed_packet =8M sort_buffer_size = 1M join_buffer_size = 1M thread_cache_size = 100 thread_concurrency = 2 query_cache_size = 2M query_cache_limit = 1M query_cache_min_res_unit = 2k thread_stack = 192K tmp_table_size = 2M max_heap_table_size = 2M long_query_time = 1 pid-file = /data/3307/mysql.pid relay-log = /data/3307/relay-bin relay-log-info-file = /data/3307/relay-log.info binlog_cache_size = 1M max_binlog_cache_size = 1M max_binlog_size = 2M expire_logs_days = 7 key_buffer_size = 16M read_buffer_size = 1M read_rnd_buffer_size = 1M bulk_insert_buffer_size = 1M lower_case_table_names = 1 skip-name-resolve slave-skip-errors = 1032,1062 replicate-ignore-db=mysql server-id = 5

        说明：对比两个配置文件之后，可以发现除了端口、server-id不一样，3306开启了log-bin功能，这样可以做MySQL主复制

四、MySQL多实例启动命令脚本

#!/bin/sh
#init
port=3306
mysql_user="root"
mysql_pwd="123456"
CmdPath="/application/mysql/bin"
mysql_sock="/data/${port}/mysql.sock"
#startup function
function_start_mysql()
{
    if [ ! -e "$mysql_sock" ];then
      printf "Starting MySQL...
"
      /bin/sh ${CmdPath}/mysqld_safe --defaults-file=/data/${port}/my.cnf 2>&1 > /dev/null &
    else
      printf "MySQL is running...
"
      exit
    fi
}

#stop function
function_stop_mysql()
{
    if [ ! -e "$mysql_sock" ];then
       printf "MySQL is stopped...
"
       exit
    else
       printf "Stoping MySQL...
"
       ${CmdPath}/mysqladmin -u ${mysql_user} -p${mysql_pwd} -S /data/${port}/mysql.sock shutdown
   fi
}

#restart function
function_restart_mysql()
{
    printf "Restarting MySQL...
"
    function_stop_mysql
    sleep 2
    function_start_mysql
}

case $1 in
start)
    function_start_mysql
;;
stop)
    function_stop_mysql
;;
restart)
    function_restart_mysql
;;
*)
    printf "Usage: /data/${port}/mysql {start|stop|restart}
"
esac

五、遇到的错误

1、[ERROR] Plugin 'InnoDB' init function returned error

       删除MySQL目录下的ib_logfile0和ib_logfile1两个文件，就可以解决问题了

2、5.5.32——>5.6.36配置参数不对导致多实例无法启动

      table_cache——>table_open_cache = 512(5.6改名了)

六、生产环境多实例配置环境

1、一般在1-4个实例之间居多，1-2个最多，大业务占用的机器比较多，机器R510居多，CPU是E5210，48G内存，硬盘12*300G SAS,RAID10

2、内存32G，双cpu8核，硬盘6X600G，跑2-3个实例