1 介绍
MySQL Group Replication（简称MGR）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。MySQL组复制提供了高可用、高扩展、高可靠的MySQL集群服务。
-
高一致性，基于原生复制及paxos协议的组复制技术，并以插件的方式提供，提供一致数据安全保证；
-
高容错性，只要不是大多数节点坏掉就可以继续工作，有自动检测机制，当不同节点产生资源争用冲突时，不会出现错误，按照先到者优先原则进行处理，并且内置了自动化脑裂防护机制；
-
高扩展性，节点的新增和移除都是自动的，新节点加入后，会自动从其他节点上同步状态，直到新节点和其他节点保持一致，如果某节点被移除了，其他节点自动更新组信息，自动维护新的组信息；
-
高灵活性，有单主模式和多主模式，单主模式下，会自动选主，所有更新操作都在主上进行；多主模式下，所有server都可以同时处理更新操作。
MGR是MySQL数据库未来发展的一个重要方向。
2 环境准备
2.1 数据库服务器规划
| 序号 | IP地址 | 主机名 | 数据库 | 数据库端口号 | 数据库Server ID | 备注 |
|---|---|---|---|---|---|---|
| 1 | 192.168.56.181 | apollo.mgr.com | mysql-5.7 | 3306 | 181 | 操作系统7 |
| 2 | 192.168.56.182 | artemis.mgr.com | mysql-5.7 | 3306 | 182 | 操作系统CentOS7 |
| 3 | 192.168.56.183 | uranus.mgr.com | mysql-5.7 | 3306 | 183 | 操作系统CentOS7 |
2.2 安装mysql5.7.17
2.3 设置hostname和ip映射
在三台数据库服务器上都设置： 
[mgradmin@apollo mysql-5.7.17-1.el7.x86_64.rpm-bundle]$ vim /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.56.181 apollo.mgr.com
192.168.56.182 artemis.mgr.com
192.168.56.183 uranus.mgr.com3. 创建复制环境
3.1 服务器apollo.mgr.com
3.1.1 配置/etc/my.cnf
[mgradmin@apollo mysql-5.7.17-1.el7.x86_64.rpm-bundle]$ sudo vim /etc/my.cnf
# For advice on how to change settings please see
# http://dev.mysql.com/doc/refman/5.7/en/server-configuration-defaults.html
[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
#
# 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
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
# Group Replication
server_id = 181
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 = 'apollo.mgr.com:33061'
loose-group_replication_group_seeds ='apollo.mgr.com:33061,artemis.mgr.com:33062,uranus.mgr.com:33063'
loose-group_replication_bootstrap_group = off
3.1.2 服务器apollo.mgr.com上建立复制账号：
mysql> set SQL_LOG_BIN=0;
mysql> create user repl@'%' identified by 'Love88me=-.,';
mysql> grant replication slave on *.* to repl@'%';
mysql> flush privileges;
mysql> set SQL_LOG_BIN=1;
mysql> change master to master_user='repl',master_password='Love88me=-.,' for channel 'group_replication_recovery'; -- 构建group replication集群3.1.3 在mysql服务器apollo.mgr.com上安装group replication插件
-- 安装插件
mysql> install PLUGIN group_replication SONAME 'group_replication.so';
-- 查看group replication组件
mysql> show plugins;
+----------------------------+----------+--------------------+----------------------+---------+
| Name | Status | Type | Library | License |
+----------------------------+----------+--------------------+----------------------+---------+
| binlog | ACTIVE | STORAGE ENGINE | NULL | GPL |
| mysql_native_password | ACTIVE | AUTHENTICATION | NULL | GPL |
| sha256_password | ACTIVE | AUTHENTICATION | NULL | GPL |
| CSV | ACTIVE | STORAGE ENGINE | NULL | GPL |
| MEMORY | ACTIVE | STORAGE ENGINE | NULL | GPL |
| InnoDB | ACTIVE | STORAGE ENGINE | NULL | GPL |
| INNODB_TRX | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_LOCKS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_LOCK_WAITS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_CMP | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_CMP_RESET | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_CMPMEM | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_CMPMEM_RESET | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_CMP_PER_INDEX | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_CMP_PER_INDEX_RESET | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_BUFFER_PAGE | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_BUFFER_PAGE_LRU | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_BUFFER_POOL_STATS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_TEMP_TABLE_INFO | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_METRICS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_FT_DEFAULT_STOPWORD | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_FT_DELETED | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_FT_BEING_DELETED | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_FT_CONFIG | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_FT_INDEX_CACHE | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_FT_INDEX_TABLE | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_TABLES | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_TABLESTATS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_INDEXES | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_COLUMNS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_FIELDS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_FOREIGN | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_FOREIGN_COLS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_TABLESPACES | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_DATAFILES | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_VIRTUAL | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| MyISAM | ACTIVE | STORAGE ENGINE | NULL | GPL |
| MRG_MYISAM | ACTIVE | STORAGE ENGINE | NULL | GPL |
| PERFORMANCE_SCHEMA | ACTIVE | STORAGE ENGINE | NULL | GPL |
| ARCHIVE | ACTIVE | STORAGE ENGINE | NULL | GPL |
| BLACKHOLE | ACTIVE | STORAGE ENGINE | NULL | GPL |
| FEDERATED | DISABLED | STORAGE ENGINE | NULL | GPL |
| partition | ACTIVE | STORAGE ENGINE | NULL | GPL |
| ngram | ACTIVE | FTPARSER | NULL | GPL |
| validate_password | ACTIVE | VALIDATE PASSWORD | validate_password.so | GPL |
| group_replication | ACTIVE | GROUP REPLICATION | group_replication.so | GPL |
+----------------------------+----------+--------------------+----------------------+---------+3.1.4 启动服务器apollo.mgr.com上mysql的group replication
-- 设置group_replication_bootstrap_group为ON是为了标示以后加入集群的服务器以这台服务器为基准，以后加入的就不需要设置。
mysql> set global group_replication_bootstrap_group=ON;
-- 作为首个节点启动mgr集群
mysql> start group_replication;
mysql> set global group_replication_bootstrap_group=OFF;3.1.5 查看mgr的状态
-- 查询表performance_schema.replication_group_members
mysql> select * from performance_schema.replication_group_members;
+---------------------------+--------------------------------------+----------------+-------------+--------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE |
+---------------------------+--------------------------------------+----------------+-------------+--------------+
| group_replication_applier | ecf48652-1c72-11e7-a7c1-08002785d027 | apollo.mgr.com | 3306 | ONLINE |
+---------------------------+--------------------------------------+----------------+-------------+--------------+3.1.6 测试服务器apollo.mgr.com上的mysql
mysql> create database test;
Query OK, 1 row affected (0.01 sec)
mysql> use test;
Database changed
mysql> create table t1(c1 int primary key, c2 text not null);
Query OK, 0 rows affected (0.01 sec)
mysql> insert into t1 values (1, 'Luis');
Query OK, 1 row affected (0.01 sec)
mysql> select * from t1;
+----+------+
| c1 | c2 |
+----+------+
| 1 | Luis |
+----+------+
1 row in set (0.00 sec)
mysql> show binlog events;
+---------------+-----+----------------+-----------+-------------+-------------------------------------------------------------------+
| Log_name | Pos | Event_type | Server_id | End_log_pos | Info |
+---------------+-----+----------------+-----------+-------------+-------------------------------------------------------------------+
| binlog.000001 | 4 | Format_desc | 181 | 123 | Server ver: 5.7.17-log, Binlog ver: 4 |
| binlog.000001 | 123 | Previous_gtids | 181 | 150 | |
| binlog.000001 | 150 | Gtid | 181 | 211 | SET @@SESSION.GTID_NEXT= 'ce9be252-2b71-11e6-b8f4-00212844f856:1' |
| binlog.000001 | 211 | Query | 181 | 270 | BEGIN |
| binlog.000001 | 270 | View_change | 181 | 369 | view_id=14916679781649312:1 |
| binlog.000001 | 369 | Query | 181 | 434 | COMMIT |
| binlog.000001 | 434 | Gtid | 181 | 495 | SET @@SESSION.GTID_NEXT= 'ce9be252-2b71-11e6-b8f4-00212844f856:2' |
| binlog.000001 | 495 | Query | 181 | 585 | create database test |
| binlog.000001 | 585 | Gtid | 181 | 646 | SET @@SESSION.GTID_NEXT= 'ce9be252-2b71-11e6-b8f4-00212844f856:3' |
| binlog.000001 | 646 | Query | 181 | 769 | use `test`; create table t1(c1 int primary key, c2 text not null) |
| binlog.000001 | 769 | Gtid | 181 | 830 | SET @@SESSION.GTID_NEXT= 'ce9be252-2b71-11e6-b8f4-00212844f856:4' |
| binlog.000001 | 830 | Query | 181 | 898 | BEGIN |
| binlog.000001 | 898 | Table_map | 181 | 941 | table_id: 219 (test.t1) |
| binlog.000001 | 941 | Write_rows | 181 | 983 | table_id: 219 flags: STMT_END_F |
| binlog.000001 | 983 | Xid | 181 | 1010 | COMMIT /* xid=40 */ |
+---------------+-----+----------------+-----------+-------------+-------------------------------------------------------------------+
15 rows in set (0.00 sec)3.2 复制组添加新实例artemis.mgr.com
3.2.1 修改/etc/my.cnf 配置文件，方法和之前相同
# For advice on how to change settings please see
# http://dev.mysql.com/doc/refman/5.7/en/server-configuration-defaults.html
[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
#
# 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
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
# Group Replication
server_id = 182
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 = 'artemis.mgr.com:33062'
loose-group_replication_group_seeds ='apollo.mgr.com:33061,artemis.mgr.com:33062,uranus.mgr.com:33063'
loose-group_replication_bootstrap_group = off3.2.2 用户凭证
mysql> set SQL_LOG_BIN=0;
Query OK, 0 rows affected (0.00 sec)
mysql> create user repl@'%' identified by 'Love88me=-.,';
Query OK, 0 rows affected (0.00 sec)
mysql> grant replication slave on *.* to repl@'%';
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> SET SQL_LOG_BIN=1;
Query OK, 0 rows affected (0.00 sec)
mysql> change master to master_user='repl',master_password='Love88me=-.,' for channel 'group_replication_recovery';
Query OK, 0 rows affected, 2 warnings (0.02 sec)
-- 安装group replication插件
mysql> install PLUGIN group_replication SONAME 'group_replication.so';
Query OK, 0 rows affected (0.00 sec)3.2.3 把实例添回到之前的复制组
mysql> set global group_replication_allow_local_disjoint_gtids_join=ON;
Query OK, 0 rows affected (0.00 sec)
mysql> start group_replication;
Query OK, 0 rows affected (6.65 sec)3.2.4 在apollo.mgr.com上查看复制组状态
mysql> select * from performance_schema.replication_group_members;
+---------------------------+--------------------------------------+-----------------+-------------+--------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE |
+---------------------------+--------------------------------------+-----------------+-------------+--------------+
| group_replication_applier | ecf48652-1c72-11e7-a7c1-08002785d027 | apollo.mgr.com | 3306 | ONLINE |
| group_replication_applier | f0a20978-1c72-11e7-a17b-0800272ce349 | artemis.mgr.com | 3306 | ONLINE |
+---------------------------+--------------------------------------+-----------------+-------------+--------------+3.2.5 在新回的实例上查看数据库发现test库和t1表已经同步
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| test |
+--------------------+
5 rows in set (0.00 sec)
mysql> use test;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| t1 |
+----------------+
1 row in set (0.00 sec)
mysql> select * from t1;
+----+------+
| c1 | c2 |
+----+------+
| 1 | Luis |
+----+------+
1 row in set (0.00 sec)3.3 以同样方法添加uranus.mgr.com
详细步骤请参考3.2, 这里只给出配置文件/etc/my.cnf：
扫描二维码关注公众号，回复：
1957962 查看本文章
# For advice on how to change settings please see
# http://dev.mysql.com/doc/refman/5.7/en/server-configuration-defaults.html
[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
#
# 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
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
# Group Replication
server_id = 183
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 = 'uranus.mgr.com:33063'
loose-group_replication_group_seeds ='apollo.mgr.com:33061,artemis.mgr.com:33062,uranus.mgr.com:33063'
loose-group_replication_bootstrap_group = off3.4 查看复制组状态
mysql> select * from performance_schema.replication_group_members;
+---------------------------+--------------------------------------+-----------------+-------------+--------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE |
+---------------------------+--------------------------------------+-----------------+-------------+--------------+
| group_replication_applier | ecf48652-1c72-11e7-a7c1-08002785d027 | apollo.mgr.com | 3306 | ONLINE |
| group_replication_applier | f0a20978-1c72-11e7-a17b-0800272ce349 | artemis.mgr.com | 3306 | ONLINE |
| group_replication_applier | f2ca816c-1c72-11e7-a1aa-080027eaa4e1 | uranus.mgr.com | 3306 | ONLINE |
+---------------------------+--------------------------------------+-----------------+-------------+--------------+