安装mysql 5.7.23
打开 http://repo.mysql.com/ 找到最新的，如mysql57-community-release-el7-11.noarch.rpm
wget http://repo.mysql.com/mysql57-community-release-el7-11.noarch.rpm
rpm -ivh mysql57-community-release-el7-11.noarch.rpm
ll /etc/yum.repos.d/
如想加速，执行 wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
yum install mysql-server
设置，
1.开启慢查询
long-query-time=3
slow-query-log=1
slow-query-log-file=/var/log/mysql/log-slow-queries.log
2.获取临时密码
grep "temporary" /var/log/mysqld.log 或 grep "password" /var/log/mysqld.log
3.改密码，不修改无法进行其他操作
SET PASSWORD = PASSWORD('your new password');
ALTER USER 'root'@'localhost' PASSWORD EXPIRE NEVER;
FLUSH PRIVILEGES;
———————————至此安装已完成，下面是MGR的设置———————————
MGR的设置
编辑/etc/my.cnf
1.设置MGR复制框架 , 开启binlog
server_id=3 （id自填）
gtid_mode=ON
enforce_gtid_consistency=ON
master_info_repository=TABLE
relay_log_info_repository=TABLE
log_slave_updates=ON
log_bin=binlog （默认值log_bin即为binlog，可以不加=binlog）
binlog_format=ROW
binlog_checksum=NONE
2.设置MGR
transaction_write_set_extraction=XXHASH64 (server必须为每个事务收集写集合，并使用XXHASH64哈希算法将其编码为散列)
loose-group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa" （告知插件加入或创建组名，必须是UUID，可用工具创建）
loose-group_replication_start_on_boot=off (server启动时不自启组复制)
loose-group_replication_local_address="n0:13306" (告诉插件使用主机名或IP，自定义端口13306用于接收组中其他成员转入连接，端口可改 )
loose-group_replication_group_seeds="n0:13306,n1:13306,n2:13306" (启动组server，种子server，加入组应该连接这些主机和端口；其他server要加入组得由组成员同意)
loose-group_replication_ip_whitelist='n0,n1,n2' （可以忽略不写）
loose-group_replication_bootstrap_group=off （表示是否启动MySQL分组，在一个分组中，只应当允许一个成员启动MySQL分组）
loose-group_replication_single_primary_mode=off （ 多主模式须为off ，单主模式为on）
loose-group_replication_enforce_update_everywhere_checks=true （ 多主模式须为true，单主模式为false）
以下操作均是登录mysql后进行
3.创建MGR的复制账号，并授权
#下面操纵不写入二进制日志，避免修改传递给其他服务器，先关闭完成后再开启；
set sql_log_bin=0;
create user rpl_user@'%' identified by 'rpl_pass'; #创建拥有replication slave权限mysql用户，用户名可自行替换
grant replication slave on *.* to rpl_user@'%' ;
flush privileges;
set sql_log_bin=1;
4 设置group_replication_recovery
#change master to命令将server配置为在下次需要从其他成员恢复状态时，使用group_replication_recovery复制通道的给定账号密码
change master to master_user='rpl_user',master_password='rpl_pass' for channel 'group_replication_recovery';
5.安装组复制插件
install plugin group_replication soname 'group_replication.so';
show plugins
6.启动
6-9操作均是登录mysql后进行
# 第1台服务器启动组复制，复制组只须启动一次，第1台服务器和其他服务器在此次之后都无需再做以下操作
set global group_replication_bootstrap_group=ON;
start group_replication;
set global group_replication_bootstrap_group=OFF;
7 其他服务器设置
重复1-5的步骤
8.其他服务器启动及加入集群
set global group_replication_allow_local_disjoint_gtids_join=ON; 非必须如提示错误则运行
start group_replication;
9. 检测组是否创建并已加入新成员
select * from performance_schema.replication_group_members;
----------------------------------排错----------------------------------------------------------------
[ERROR] Plugin group_replication reported: 'For details please check performance_schema.replication_connection_status table and error log messages of Slave I/O for channel group_replication_recovery.'
select * from performance_schema.replication_group_members; 查出主机名
修改/etc/hosts 把主机名添加进去，也可用IP代替主机名但不一定有效
2018-08-29T03:07:33.494884Z 0 [ERROR] Plugin group_replication reported: 'This member has more executed transactions than those present in the group. Local transactions: ecd4c59e-3bdc-11e8-9582-525400373379:1-4 > Group transactions: aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:1-46'
2018-08-29T03:07:33.494916Z 0 [ERROR] Plugin group_replication reported: 'The member contains transactions not present in the group. The member will now exit the group.'
2018-08-29T03:07:33.494919Z 0 [Note] Plugin group_replication reported: 'To force this member into the group you can use the group_replication_allow_local_disjoint_gtids_join option'
解决：set global group_replication_allow_local_disjoint_gtids_join=ON;
出错重启，先STOP GROUP_REPLICATION; 再START GROUP_REPLICATION;
注意：开启防火墙和SELinux会导致失败
---------------------------------其他指令----------------------------------------------------------
show global status like '%group_replication_primary%'; 仅适用于单主模式
show variables where Variable_name like '%hostname%'; 显示主机IP
参考：https://www.cnblogs.com/jorzy/p/8455519.html
https://dev.mysql.com/doc/refman/5.7/en/group-replication-configuring-instances.html
https://www.cnblogs.com/shengdimaya/p/8436112.html
http://axiaoxin.com/article/237/
