此搭建试验为5.7GR刚出三天左右搭建的，可能现在又有变化，最近京东出了个搭建文档可以瞅一下
多台服务器相比单台服务器搭建 group replication 需要注意几个点:
1、各个服务器之间需要添加解析：
127.0.0.1 VM-172-31-102-3 localhost localhost.localdomain localhost4 localhost4.localdomain4
172.31.102.243 VM-172-31-102-243
172.31.102.3 VM-172-31-102-3
172.31.102.86 VM-172-31-102-86
2、需要添加白名单参数：
loose-group_replication_ip_whitelist='172.31.102.243/24,172.31.102.3/24,172.31.102.86/24,127.0.0.1/8'
3、 两种模式
mysql5.7.17 Group Replication提供了single-primary和multi-primary两种模式。single-primary mode 组内只有一个节点负责写入，
读可以从任意一个节点读取，组内数据保持强一致；而multi-primary mode 为多写，即写会下发到组内所有节点，组内所有节点同时可读，
也是能够保证组内数据强一致性。一个group的所有节点必须配置使用同一种模式，不可混用。
Single-Primary Mode
这个模式下，group内只有一台节点可写可读，其他节点只可以读。对于group的部署，
需要先跑起primary节点(即那个可写可读的节点)，然后再跑起其他的节点，并把这些节点一一加进group。
其他的节点就会自动同步primary节点上面的变化，然后将自己设置为只读模式。
当primary节点意外宕机或者下线，在满足大多数机器存活的情况下，group内部发起选举，选出下一个可用的读节点，提升为primary节点
multi-primary模式：
1、该模式启用需设置两个参数
group_replication_single_primary_mode=0 #这个参数很好理解，就是关闭单master模式
group_replication_enforce_update_everywhere_checks=1 #这个参数设置检查对RP又影响的参数在各个节点是否一致
2、默认启动的都是单master模式，其他节点都设置了read_only、super_read_only这两个参数，需要修改这两个配置
3、完成上面的配置后就可以执行多点写入了，多点写入会存在冲突检查，这耗损性能挺大的，官方建议采用网络分区功能，
在程序端把相同的业务定位到同一节点，尽量减少冲突发生几率
--------------------------------------------------搭建：
一、初始化数据库：
-----5.7安装配置
yum install gcc gcc-c++ -y
yum install -y ncurses-devel.x86_64
yum install -y cmake.x86_64
yum install -y libaio.x86_64
yum install -y bison.x86_64
yum install -y gcc-c++.x86_64
yum install –y autoconf automake imake libxml2-devel expat-devel cmake gcc gcc-c++ libaio libaio-devel bzr bison libtool ncurses5-devel ncurses-devle
yum install -y libaio*
安装boost
./bootstrap.sh
./b2 install
vi /etc/my.cnf
以下为搭建GA的最基本参数，其他优化参数可根据具体情况添加：
##############################################################################
[mysqld]
basedir = /usr/local/mysql
datadir = /data/mysql
user=mysql
explicit_defaults_for_timestamp
port = 3306
server_id = 2
socket = /tmp/mysql.sock
pid-file = /tmp/mysql.pid
# log settings #
log-error = /data/log/3306.err
#binlog binlog
log-bin=mysql-bin
binlog-format = ROW
gtid-mode = ON
enforce-gtid-consistency = ON
log-slave-updates = ON
master-info-repository = TABLE
relay-log-info-repository = TABLE
binlog-checksum = NONE
#group replication
transaction_write_set_extraction=XXHASH64
loose-group_replication_start_on_boot=off
loose-group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"
loose-group_replication_local_address= '172.31.102.243:6606'
loose-group_replication_group_seeds= '172.31.102.243:6606,172.31.102.3:6606,172.31.102.86:6606'
loose-group_replication_ip_whitelist='172.31.102.243/24,172.31.102.3/24,172.31.102.86/24,127.0.0.1/8'
loose-group_replication_bootstrap_group= off
#loose-group-group_replication_single_primary_mode=0
#loose-group-group_replication_enforce_update_everywhere_checks=1
##############################################################################
---注册服务
useradd mysql
cp ./support-files/mysql.server /etc/init.d/mysqld
mkdir -p /data/mysql
mkdir -p /data/log
mkdir -p /data/binlog
mkdir -p /data/undolog
chmod 755 /etc/init.d/mysqld
chown -R mysql:mysql /opt/mysql
chown -R mysql:mysql /data
ln -s /opt/mysql/bin/* /usr/bin/
--不生成随机密码
./mysqld --initialize-insecure --user=mysql --basedir=/usr/local/mysql --datadir=/data/mysql
三、启动数据库
service mysqld start
四、配置第一个节点
SET SQL_LOG_BIN=0;
alter user 'root'@'localhost' identified by 'root';
CREATE USER rpl_user@'%';
GRANT REPLICATION SLAVE ON *.* TO rpl_user@'%' IDENTIFIED BY 'rpl_pass';
SET SQL_LOG_BIN=1;
CHANGE MASTER TO MASTER_USER='rpl_user', MASTER_PASSWORD='rpl_pass'
FOR CHANNEL 'group_replication_recovery';
INSTALL PLUGIN group_replication SONAME 'group_replication.so';
mysql> SHOW PLUGINS;
+----------------------------+----------+--------------------+----------------------+-------------+
| Name | Status | Type | Library | License |
+----------------------------+----------+--------------------+----------------------+-------------+
| binlog | ACTIVE | STORAGE ENGINE | NULL | PROPRIETARY |
(...)
| group_replication | ACTIVE | GROUP REPLICATION | group_replication.so | PROPRIETARY |
+----------------------------+----------+--------------------+----------------------+-------------+
SET GLOBAL group_replication_bootstrap_group=ON;
START GROUP_REPLICATION;
SET GLOBAL group_replication_bootstrap_group=OFF;
mysql> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+-------------------+-------------+--------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE |
+---------------------------+--------------------------------------+-------------------+-------------+--------------+
| group_replication_applier | 0e39bfb1-c367-11e6-a5e4-0200621600c2 | VM-172-31-102-243 | 3306 | ONLINE |
+---------------------------+--------------------------------------+-------------------+-------------+--------------+
1 row in set (0.00 sec)
mysql> CREATE DATABASE test;
Query OK, 1 row affected (0,00 sec)
mysql> use test
Database changed
mysql> CREATE TABLE t1 (c1 INT PRIMARY KEY, c2 TEXT NOT NULL);
Query OK, 0 rows affected (0,00 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 | 1 | 123 | Server ver: 5.7.17-gr080-log, Binlog ver: 4 |
| binlog.000001 | 123 | Previous_gtids | 1 | 150 | |
| binlog.000001 | 150 | Gtid | 1 | 211 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:1' |
| binlog.000001 | 211 | Query | 1 | 270 | BEGIN |
| binlog.000001 | 270 | View_change | 1 | 369 | view_id=14724817264259180:1 |
| binlog.000001 | 369 | Query | 1 | 434 | COMMIT |
| binlog.000001 | 434 | Gtid | 1 | 495 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:2' |
| binlog.000001 | 495 | Query | 1 | 585 | CREATE DATABASE test |
| binlog.000001 | 585 | Gtid | 1 | 646 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:3' |
| binlog.000001 | 646 | Query | 1 | 770 | use `test`; CREATE TABLE t1 (c1 INT PRIMARY KEY, c2 TEXT NOT NULL) |
| binlog.000001 | 770 | Gtid | 1 | 831 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:4' |
| binlog.000001 | 831 | Query | 1 | 899 | BEGIN |
| binlog.000001 | 899 | Table_map | 1 | 942 | table_id: 108 (test.t1) |
| binlog.000001 | 942 | Write_rows | 1 | 984 | table_id: 108 flags: STMT_END_F |
| binlog.000001 | 984 | Xid | 1 | 1011 | COMMIT /* xid=38 */ |
+---------------+-----+----------------+-----------+-------------+--------------------------------------------------------------------+
15 rows in set (0,00 sec)
五、加入其它节点
--二三节点配置：
##############################################################################
[mysqld]
basedir = /usr/local/mysql
datadir = /data/mysql
user=mysql
explicit_defaults_for_timestamp
port = 3306
server_id = 2
socket = /tmp/mysql.sock
pid-file = /tmp/mysql.pid
# log settings #
log-error = /data/log/3306.err
#binlog binlog
log-bin=mysql-bin
binlog-format = ROW
gtid-mode = ON
enforce-gtid-consistency = ON
log-slave-updates = ON
master-info-repository = TABLE
relay-log-info-repository = TABLE
binlog-checksum = NONE
#relay-log=VM-172-31-102-3-relay-bin
#skip-name-resolve
#group replication
transaction_write_set_extraction=XXHASH64
loose-group_replication_start_on_boot=off
loose-group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"
loose-group_replication_local_address= '172.31.102.3:6606'
loose-group_replication_group_seeds= '172.31.102.243:6606,172.31.102.3:6606,172.31.102.86:6606'
loose-group_replication_ip_whitelist='172.31.102.243/24,172.31.102.3/24,172.31.102.86/24,127.0.0.1/8'
loose-group_replication_bootstrap_group= off
#loose-group-group_replication_single_primary_mode=0
#loose-group-group_replication_enforce_update_everywhere_checks=1
##############################################################################
##############################################################################
[mysqld]
basedir = /usr/local/mysql
datadir = /data/mysql
user=mysql
explicit_defaults_for_timestamp
port = 3306
server_id = 3
socket = /tmp/mysql.sock
pid-file = /tmp/mysql.pid
# log settings #
log-error = /data/log/3306.err
log-bin=/data/binlog/mysql-bin
#binlog binlog
log-bin=mysql-bin
binlog-format = ROW
gtid-mode = ON
enforce-gtid-consistency = ON
log-slave-updates = ON
master-info-repository = TABLE
relay-log-info-repository = TABLE
binlog-checksum = NONE
#group replication
transaction_write_set_extraction=XXHASH64
loose-group_replication_start_on_boot=off
loose-group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"
loose-group_replication_local_address= '172.31.102.86:6606'
loose-group_replication_group_seeds= '172.31.102.3:6606,172.31.102.243:6606,172.31.102.86:6606'
loose-group_replication_ip_whitelist='172.31.102.243/24,172.31.102.3/24,172.31.102.86/24'
loose-group_replication_bootstrap_group= off
#loose-group-group_replication_single_primary_mode=0
#loose-group-group_replication_enforce_update_everywhere_checks=1
##############################################################################
--加入节点：（二三节点依次执行）
INSTALL PLUGIN group_replication SONAME 'group_replication.so';
SET SQL_LOG_BIN=0;
alter user 'root'@'localhost' identified by 'root';
CREATE USER rpl_user@'%';
GRANT REPLICATION SLAVE ON *.* TO rpl_user@'%' IDENTIFIED BY 'rpl_pass';
FLUSH PRIVILEGES;
SET SQL_LOG_BIN=1;
CHANGE MASTER TO MASTER_USER='rpl_user', MASTER_PASSWORD='rpl_pass' FOR CHANNEL 'group_replication_recovery';
START GROUP_REPLICATION;
--下列抱错可能会因初始化参数执行顺序问题出现:
[ERROR] Plugin group_replication reported: 'This member has more executed transactions than those present in the group.
Local transactions:
--执行跳过该事物：
SET GLOBAL group_replication_allow_local_disjoint_gtids_join=ON;
搭建完毕：
mysql> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+-------------------+-------------+--------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE |
+---------------------------+--------------------------------------+-------------------+-------------+--------------+
| group_replication_applier | 69717cb5-c59d-11e6-b788-020027b4009a | VM-172-31-102-86 | 3306 | ONLINE |
| group_replication_applier | b55a9513-c734-11e6-821a-02007de500c1 | VM-172-31-102-3 | 3306 | ONLINE |
| group_replication_applier | c0d38ada-c730-11e6-8cdc-0200621600c2 | VM-172-31-102-243 | 3306 | ONLINE |
+---------------------------+--------------------------------------+-------------------+-------------+--------------+
3 rows in set (0.00 sec)