版本说明

本文写于 2022-03，基于 MySQL 8.0 Group Replication。
MGR 的核心机制（Paxos 协议、单主/多主模式）未变，经 2026-07 复核仍适用；8.0 后续小版本对 MGR 的自动化运维（如 group_replication_communication_stack 参数、Clone 插件配合分布式恢复）有增强，新部署建议一并核对官方最新文档。

MGR 部署

my.cnf配置参数

单主配置

#--- group replication settings ---
plugin-load = "group_replication.so"
transaction-write-set-extraction = XXHASH64
report_host = 172.16.0.83
binlog_checksum = NONE
loose_slave_preserve_commit_order = on 
loose_group_replication = FORCE_PLUS_PERMANENT
loose_group_replication_group_name = "f0d9e877-661b-487c-a955-7fae37a5c2bd"
loose_group_replication_compression_threshold = 100000       # mysql8.0.11后默认值为1000000字节,1M
loose_group_replication_flow_control_mode = 0
loose_group_replication_single_primary_mode = 1
loose_group_replication_transaction_size_limit = 331350016
loose_group_replication_member_expel_timeout = 20
loose_group_replication_unreachable_majority_timeout = 20
loose_group_replication_start_on_boot = off
loose_group_replication_local_address = '172.16.0.83:23502' #端口跟mysql端口不同即可
loose_group_replication_group_seeds = '172.16.0.82:23501,172.16.0.83:23502,172.16.0.84:23503'
loose_group_replication_ip_whitelist= '172.16.0.0/20'
loose_group_replication_bootstrap_group = off		

多主配置

##--- group replication settings 多主模式---
plugin-load = "group_replication.so"
transaction-write-set-extraction = XXHASH64
report_host = 172.16.0.87
binlog_checksum = NONE
loose_slave_preserve_commit_order = on 
loose_group_replication = FORCE_PLUS_PERMANENT
loose_group_replication_group_name = "00000000-0000-0000-0000-000000000000"
loose_group_replication_compression_threshold = 100000       # mysql8.0.11后默认值为1000000字节,1M
loose_group_replication_flow_control_mode = 0
loose_group_replication_single_primary_mode = 0
loose_group_replication_enforce_update_everywhere_checks = ON # 比单主多了这一行
loose_group_replication_transaction_size_limit = 331350016
loose_group_replication_member_expel_timeout = 20
loose_group_replication_unreachable_majority_timeout = 20
loose_group_replication_start_on_boot = off
loose_group_replication_local_address = '172.16.0.87:23306'
loose_group_replication_group_seeds = '172.16.0.87:23306,172.16.0.88:23306,172.16.0.89:23306'
loose_group_replication_ip_whitelist= '0.0.0.0/20'
loose_group_replication_bootstrap_group = off	

1.先创建一个用户

create user 'repl'@'172.16.0.%' identified by 'xxxxxxxxx';

再进行授权

grant REPLICATION SLAVE on *.* to 'repl'@'172.16.0.%' ;

2.安装插件

install plugin group_replication soname 'group_replication.so';

show plugins;

select * from INFORMATION_SCHEMA.PLUGINS where PLUGIN_NAME like '%group_replication%';

INSTALL PLUGIN clone SONAME 'mysql_clone.so';		#可选

3.配置master实例

1）查看当前的group replication相关参数是否配置有误

show global variables like 'group%';

2）启动 group_replication_bootstrap_group

SET GLOBAL group_replication_bootstrap_group=ON;

3）配置MGR

set global  group_replication_ip_whitelist='10.100.101.0/20';
CHANGE MASTER TO MASTER_USER='repl', MASTER_PASSWORD='EKxxxxxxxxxxxdgJ' FOR CHANNEL 'group_replication_recovery';

4）启动MGR

start group_replication;

5）关闭 group_replication_bootstrap_groups

SET GLOBAL group_replication_bootstrap_group=OFF;

select * from performance_schema.replication_group_members;

Q&A

show global variables like '%gtid%' ;
set @@GLOBAL.GTID_PURGED='aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:1-1006103';