linux運維、架構之路-MySQL多實例

一、MySQL多實例介紹

           一台服務器上開啟多個不同的服務端口（3306，3307,3308），運行多個MySQL服務進程，共用一套MySQL安裝程序,多實例MySQL在邏輯上看是各自獨立的

1、多實例主從復制原理圖

2、優點

①有效利用服務器資源
②節約服務器資源
③資源互相搶占問題，其中一個實例並發很高或者慢查詢，其它實例也受影響

3、應用場景

①公司資金緊缺
②並發訪問不是特別大的業務
③門戶網站應用MySQL多實例場景，一般是從庫

4、MySQL多實例常見配置方案

①多配置文件、多啟動程序的方案（常用）
②單一配置文件、單一啟動程序多實例方案（一個配置文件，不好管理，耦合度太高，）

二、MySQL多實例部署

1、環境

[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、安裝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、配置多實例啟動命令和配置文件目錄

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

4、unzip data.zip 在/下直接解壓覆蓋/data目錄(注：data.zip是打包好的多實例配置文件、數據、啟動命令)

[root@MySQL data]# tree 
.
├── 3306
│    ├── data         #3306實例數據文件目錄
│    ├── my.cnf       #3306實例配置文件
│    └── mysql        #3306實例啟動命令
└── 3307
    ├── data          #3307實例數據文件目錄
    ├── my.cnf        #3307實例配置文件
    └── mysql         #3307實例啟動命令

5、授權mysql用戶管理/data目錄

chown -R mysql.mysql /data

6、授權mysql命令執行權限

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

7、配置mysql命令啟動環境變量

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、初始化多實例數據庫

cd /application/mysql/scripts/
./mysql_install_db --basedir=/application/mysql/ --datadir=/data/3306/data/ --user=mysql #初始化數據庫3306
./mysql_install_db --basedir=/application/mysql/ --datadir=/data/3307/data/ --user=mysql #初始化數據庫3307

9、MySQL多實例服務啟動

#啟動服務 /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多實例設置密碼及登錄

#設置密碼：
mysqladmin -uroot password 123456 -S /data/3306/mysql.sock
mysqladmin -uroot password 123456 -S /data/3307/mysql.sock
#登錄數據庫，指定sock
mysql -uroot -p123456 -S /data/3306/mysql.sock
mysql -uroot -p123456 -S /data/3307/mysql.sock

三、MySQL多實例配置文件

/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

        說明：對比兩個配置文件之后，可以發現除了端口、server-id不一樣，3306開啟了log-bin功能，這樣可以做MySQL主復制

四、MySQL多實例啟動命令腳本

#!/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...\n"
      /bin/sh ${CmdPath}/mysqld_safe --defaults-file=/data/${port}/my.cnf 2>&1 > /dev/null &
    else
      printf "MySQL is running...\n"
      exit
    fi
}

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

#restart function
function_restart_mysql()
{
    printf "Restarting MySQL...\n"
    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}\n"
esac

五、遇到的錯誤

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

       刪除MySQL目錄下的ib_logfile0和ib_logfile1兩個文件，就可以解決問題了

2、5.5.32——>5.6.36配置參數不對導致多實例無法啟動

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

六、生產環境多實例配置環境

1、一般在1-4個實例之間居多，1-2個最多，大業務占用的機器比較多，機器R510居多，CPU是E5210，48G內存，硬盤12*300G SAS,RAID10

2、內存32G，雙cpu8核，硬盤6X600G，跑2-3個實例