MySQL 5.7 MGR 集群搭建

来源：split_two

blog.chinaunix.net/uid-23916356-id-5765908.html

最近看了一下mysql5.7的MGR集群挺不错的，有单主和多主模式，于是乎搭建测试了一下效果还不错，我指的不错是搭建和维护方面都比较简单。网上绝大多数都是单主模式，当然我这里也是，为了加深印象，特意记录一下搭建过程，等以后再去尝试多主模式，相信大家现在数据库的瓶颈基本都是在写，读写分离虽然是一种可行的解决方案，但是如果数据量很大，写一样会有问题，虽然有些解决方案能部署多个主节点，能同时进行读写，但是脑裂又是一个严重的问题，所以这里MGR集群内置了自动化脑裂防护机制又得到了很多人的青睐，这里MGR简称MySQL Group Replication是MySQL官方于2016年12月推出的一个全新的高可用与高扩展的解决方案。注意本文这里不再阐述原理性的东西。

注意：我这里采用编译安装的方式，如果想简单直接yum安装mysql5.7也行，mysql编译安装需要的磁盘空间还是比较大的，一般在7G左右，所以要提前规划好，用三个节点比较接近生产环境，而且更直接清晰。

详细部署信息如下：

1、三台机器准备工作

rpm -qa mysql mariadb

如果有则卸载即可！

写入hosts文件映射关系，集群用得到

192.168.2.25 apache

192.168.2.26 nginx

192.168.2.30 kibana

2、安装依赖包

yum install gcc gcc-c++ ncurses-devel -y

3、安装cmake，下载地址：https://cmake.org/download/

tar zxvf cmake-3.7.2.tar.gz

cd make-3.7.2

./configure

gmake&& gmake install

4、安装boost，因为mysql5.7需要，注意这里下载版本是1_59_0和mysql版本是对应的，如果你的MySQL版本和我的不一样，不添加-DWITH_BOOST这个参数时它会报错告诉你需要下载boost的哪个版本。

tar zxvf boost_1_59_0.tar.gz

cp-rboost_1_59_0/usr/local/boost

5、安装mysql5.7.17及初始化操作

groupadd mysql

useradd-M-s/sbin/nologin mysql-gmysql

tar zxvf mysql-5.7.17.tar.gz

cd mysql-5.7.17

cmake-DCMAKE_INSTALL_PREFIX=/data/mysql-DSYSCONFDIR=/etc-DDEFAULT_CHARSET=utf8-DDEFAULT_COLLATION=utf8_general_ci-DWITH_EXTRA_CHARSETS=all-DWITH_BOOST=/usr/local/boost

make

make install

chown-Rmysql.mysql/data/mysql

mv/etc/my.cnf/etc/my.cnf.default

cp/data/mysql/support-files/my-default.cnf/etc/my.cnf

/data/mysql/bin/mysqld--initialize--user=mysql--basedir=/data/mysql--datadir=/data/mysql/data//注意初始化会生成一个随机的密码，请牢记

echo"PATH=$PATH:/data/mysql/bin">> /etc/profile

source/etc/profile

cp/data/mysql/support-files/mysql.server/etc/rc.d/init.d/mysqld

chmod+x/etc/rc.d/init.d/mysqld

以上步骤在三台机器上都需要执行

6、开始搭建MGR集群环境，修改第一个节点的my.cnf文件，内容如下：

# For advice on how to change settings please see

# http://dev.mysql.com/doc/refman/ ... ation-defaults.html

# *** DO NOT EDIT THIS FILE. It's a template which will be copied to the

# *** default location during install, and will be replaced if you

# *** upgrade to a newer version of MySQL.

[mysqld]

# Remove leading # and set to the amount of RAM for the most important data

# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.

# innodb_buffer_pool_size = 128M

# Remove leading # to turn on a very important data integrity option: logging

# changes to the binary log between backups.

# log_bin

# These are commonly set, remove the # and set as required.

basedir= /data/mysql

datadir= /data/mysql/data

port= 3306

socket= /data/mysql/data/mysql.sock

log-error= /data/mysql/data/mysqld.log

pid-file= /data/mysql/data/mysqld.pid

# Remove leading # to set options mainly useful for reporting servers.

# The server defaults are faster for transactions and fast SELECTs.

# Adjust sizes as needed, experiment to find the optimal values.

# join_buffer_size = 128M

# sort_buffer_size = 2M

# read_rnd_buffer_size = 2M

sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES

# Group Replication

server_id= 1

gtid_mode= ON

enforce_gtid_consistency= ON

master_info_repository= TABLE

relay_log_info_repository= TABLE

binlog_checksum= NONE

log_slave_updates= ON

log_bin= binlog

binlog_format= ROW

transaction_write_set_extraction= XXHASH64

loose-group_replication_group_name= 'ce9be252-2b71-11e6-b8f4-00212844f856'

loose-group_replication_start_on_boot= off

loose-group_replication_local_address= '192.168.2.25:33061'

loose-group_replication_group_seeds='192.168.2.25:33061,192.168.2.26:33061,192.168.2.30:33061'

loose-group_replication_bootstrap_group= off

[client]

socket= /data/mysql/data/mysql.sock

启动mysql服务

/etc/init.d/mysqld start

set sql_log_bin=0;

create user rpl_user@'%';

grant replication slave on *.* torpl_user@'%'identified by'rpl_pass';

flush privileges;

set sql_log_bin=1;

change master tomaster_user='rpl_user',master_password='rpl_pass'forchannel'group_replication_recovery';

install PLUGIN group_replication SONAME'group_replication.so';

set globalgroup_replication_bootstrap_group=ON;

start group_replication;

set globalgroup_replication_bootstrap_group=OFF;

select *from performance_schema.replication_group_members;

显示结果如下：

如果出现ONLINE，说明正常，这就是主节点，再搭建两个从节点。

7、第二个节点加入集群，复制刚刚的第一个节点的主配置文件my.cnf，只需要修改两个地方就行，已经用红色标注

# For advice on how to change settings please see

# http://dev.mysql.com/doc/refman/ ... ation-defaults.html

# *** DO NOT EDIT THIS FILE. It's a template which will be copied to the

# *** default location during install, and will be replaced if you

# *** upgrade to a newer version of MySQL.

[mysqld]

# Remove leading # and set to the amount of RAM for the most important data

# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.

# innodb_buffer_pool_size = 128M

# Remove leading # to turn on a very important data integrity option: logging

# changes to the binary log between backups.

# log_bin

# These are commonly set, remove the # and set as required.

basedir= /data/mysql

datadir= /data/mysql/data

port= 3306

socket= /data/mysql/data/mysql.sock

log-error= /data/mysql/data/mysqld.log

pid-file= /data/mysql/data/mysqld.pid

# Remove leading # to set options mainly useful for reporting servers.

# The server defaults are faster for transactions and fast SELECTs.

# Adjust sizes as needed, experiment to find the optimal values.

# join_buffer_size = 128M

# sort_buffer_size = 2M

# read_rnd_buffer_size = 2M

sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES

# Group Replication

server_id= 2

gtid_mode= ON

enforce_gtid_consistency= ON

master_info_repository= TABLE

relay_log_info_repository= TABLE

binlog_checksum= NONE

log_slave_updates= ON

log_bin= binlog

binlog_format= ROW

transaction_write_set_extraction= XXHASH64

loose-group_replication_group_name= 'ce9be252-2b71-11e6-b8f4-00212844f856'

loose-group_replication_start_on_boot= off

loose-group_replication_local_address= '192.168.2.26:33061'

loose-group_replication_group_seeds='192.168.2.25:33061,192.168.2.26:33061,192.168.2.30:33061'

loose-group_replication_bootstrap_group= off

[client]

socket= /data/mysql/data/mysql.sock

第二个节点执行如下命令：

set sql_log_bin=0;

create user rpl_user@'%';

grant replication slave on *.* torpl_user@'%'identified by'rpl_pass';

set sql_log_bin=1;

change master tomaster_user='rpl_user',master_password='rpl_pass'forchannel'group_replication_recovery';

install plugin group_replication SONAME'group_replication.so';

set globalgroup_replication_allow_local_disjoint_gtids_join=ON;

start group_replication;

显示结果如下：

同理第三个节点加入操作方法也和第二个节点一样。

截图如下：

查询哪个是主节点：

从上图来看很明显apache主机是主节点。

测试步骤：

1、在主库上创建一个库，然后创建表，在两个从库上查询数据是否同步？

2、两个从库只能执行查询操作？

3、手动关闭主库，确认两个从库其中一个是否会变成主库？而且是MEMBER_ID第一个字母按优先级排列的接管主库？

日常维护步骤：

1、如果从库某一节点关闭

start group_replication;

2、如果所有的库都关闭后，第一个库作为主库首先执行

set globalgroup_replication_bootstrap_group=ON;

start group_replication;

剩下的库直接执行即可！

start group_replication;

3、如果主库故障，会自动从两个从库选出一个主库，主库启动后再次执行如下命令后会变成从库

start group_replication;