一、创建3台MySQL环境
# 拉取镜像
docker pull mysql:8.0.20
# 创建专用网络
docker network create --subnet=172.72.0.0/24 mysql-network
# 创建目录存储数据
mkdir -p /usr/local/mysql/lhrmgr15/conf.d
mkdir -p /usr/local/mysql/lhrmgr15/data
mkdir -p /usr/local/mysql/lhrmgr16/conf.d
mkdir -p /usr/local/mysql/lhrmgr16/data
mkdir -p /usr/local/mysql/lhrmgr17/conf.d
mkdir -p /usr/local/mysql/lhrmgr17/data
# 创建3个节点的MySQL
docker run -d --name mysql8020mgr33065 \
-h lhrmgr15 -p 33065:3306 --net=mysql-network --ip 172.72.0.15 \
-v /usr/local/mysql/lhrmgr15/conf.d:/etc/mysql/conf.d -v /usr/local/mysql/lhrmgr15/data:/var/lib/mysql/ \
-e MYSQL_ROOT_PASSWORD=lhr \
-e TZ=Asia/Shanghai \
mysql:8.0.20
docker run -d --name mysql8020mgr33066 \
-h lhrmgr16 -p 33066:3306 --net=mysql-network --ip 172.72.0.16 \
-v /usr/local/mysql/lhrmgr16/conf.d:/etc/mysql/conf.d -v /usr/local/mysql/lhrmgr16/data:/var/lib/mysql/ \
-e MYSQL_ROOT_PASSWORD=lhr \
-e TZ=Asia/Shanghai \
mysql:8.0.20
docker run -d --name mysql8020mgr33067 \
-h lhrmgr17 -p 33067:3306 --net=mysql-network --ip 172.72.0.17 \
-v /usr/local/mysql/lhrmgr17/conf.d:/etc/mysql/conf.d -v /usr/local/mysql/lhrmgr17/data:/var/lib/mysql/ \
-e MYSQL_ROOT_PASSWORD=lhr \
-e TZ=Asia/Shanghai \
mysql:8.0.20
cat > /usr/local/mysql/lhrmgr15/conf.d/my.cnf <<"EOF"
[mysqld]
user=mysql
port=3306
character_set_server=utf8mb4
secure_file_priv=''
server-id = 802033065
default-time-zone = '+8:00'
log_timestamps = SYSTEM
log-bin =
binlog_format=row
binlog_checksum=NONE
log-slave-updates=1
skip-name-resolve
auto-increment-increment=2
auto-increment-offset=1
gtid-mode=ON
enforce-gtid-consistency=on
default_authentication_plugin=mysql_native_password
max_allowed_packet = 500M
master_info_repository=TABLE
relay_log_info_repository=TABLE
relay_log=lhrmgr15-relay-bin-ip15
transaction_write_set_extraction=XXHASH64
loose-group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"
loose-group_replication_start_on_boot=OFF
loose-group_replication_local_address= "172.72.0.15:33061"
loose-group_replication_group_seeds= "172.72.0.15:33061,172.72.0.16:33062,172.72.0.17:33063"
loose-group_replication_bootstrap_group=OFF
loose-group_replication_ip_whitelist="172.72.0.15,172.72.0.16,172.72.0.17"
report_host=172.72.0.15
report_port=3306
EOF
cat > /usr/local/mysql/lhrmgr16/conf.d/my.cnf <<"EOF"
[mysqld]
user=mysql
port=3306
character_set_server=utf8mb4
secure_file_priv=''
server-id = 802033066
default-time-zone = '+8:00'
log_timestamps = SYSTEM
log-bin =
binlog_format=row
binlog_checksum=NONE
log-slave-updates=1
gtid-mode=ON
enforce-gtid-consistency=ON
skip_name_resolve
default_authentication_plugin=mysql_native_password
max_allowed_packet = 500M
master_info_repository=TABLE
relay_log_info_repository=TABLE
relay_log=lhrmgr16-relay-bin-ip16
transaction_write_set_extraction=XXHASH64
loose-group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"
loose-group_replication_start_on_boot=OFF
loose-group_replication_local_address= "172.72.0.16:33062"
loose-group_replication_group_seeds= "172.72.0.15:33061,172.72.0.16:33062,172.72.0.17:33063"
loose-group_replication_bootstrap_group=OFF
loose-group_replication_ip_whitelist="172.72.0.15,172.72.0.16,172.72.0.17"
report_host=172.72.0.16
report_port=3306
EOF
cat > /usr/local/mysql/lhrmgr17/conf.d/my.cnf <<"EOF"
[mysqld]
user=mysql
port=3306
character_set_server=utf8mb4
secure_file_priv=''
server-id = 802033067
default-time-zone = '+8:00'
log_timestamps = SYSTEM
log-bin =
binlog_format=row
binlog_checksum=NONE
log-slave-updates=1
gtid-mode=ON
enforce-gtid-consistency=ON
skip_name_resolve
default_authentication_plugin=mysql_native_password
max_allowed_packet = 500M
master_info_repository=TABLE
relay_log_info_repository=TABLE
relay_log=lhrmgr16-relay-bin-ip16
transaction_write_set_extraction=XXHASH64
loose-group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"
loose-group_replication_start_on_boot=OFF
loose-group_replication_local_address= "172.72.0.17:33063"
loose-group_replication_group_seeds= "172.72.0.15:33061,172.72.0.16:33062,172.72.0.17:33063"
loose-group_replication_bootstrap_group=OFF
loose-group_replication_ip_whitelist="172.72.0.15,172.72.0.16,172.72.0.17"
report_host=172.72.0.17
report_port=3306
EOF
# 重启MySQL
docker restart mysql8020mgr33065 mysql8020mgr33066 mysql8020mgr33067
docker ps
# 进入MySQL
docker exec -it mysql8020mgr33065 bash
docker exec -it mysql8020mgr33065 mysql -uroot -plhr
#远程连接MySQL
mysql -uroot -plhr -h192.168.1.35 -P33065
mysql -uroot -plhr -h192.168.1.35 -P33066
mysql -uroot -plhr -h192.168.1.35 -P33067
# 查看MySQL日志
docker logs -f --tail 10 mysql8020mgr33065
docker logs -f --tail 10 mysql8020mgr33066
docker logs -f --tail 10 mysql8020mgr33067
# 查看MySQL的主机名、server_id和server_uuid
mysql -uroot -plhr -h192.168.1.35 -P33065 -e "select @@hostname,@@server_id,@@server_uuid"
mysql -uroot -plhr -h192.168.1.35 -P33066 -e "select @@hostname,@@server_id,@@server_uuid"
mysql -uroot -plhr -h192.168.1.35 -P33067 -e "select @@hostname,@@server_id,@@server_uuid"
结果：
[root@docker35 ~]# mysql -uroot -plhr -h192.168.1.35 -P33065 -e "select @@hostname,@@server_id,@@server_uuid"
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------+-------------+--------------------------------------+
| @@hostname | @@server_id | @@server_uuid |
+------------+-------------+--------------------------------------+
| lhrmgr15 | 802033065 | 611717fe-d785-11ea-9342-0242ac48000f |
+------------+-------------+--------------------------------------+
[root@docker35 ~]# mysql -uroot -plhr -h192.168.1.35 -P33066 -e "select @@hostname,@@server_id,@@server_uuid"
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------+-------------+--------------------------------------+
| @@hostname | @@server_id | @@server_uuid |
+------------+-------------+--------------------------------------+
| lhrmgr16 | 802033066 | 67090f47-d785-11ea-b76c-0242ac480010 |
+------------+-------------+--------------------------------------+
[root@docker35 ~]# mysql -uroot -plhr -h192.168.1.35 -P33067 -e "select @@hostname,@@server_id,@@server_uuid"
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------+-------------+--------------------------------------+
| @@hostname | @@server_id | @@server_uuid |
+------------+-------------+--------------------------------------+
| lhrmgr17 | 802033067 | 678cf064-d785-11ea-b8ce-0242ac480011 |
+------------+-------------+--------------------------------------+
[root@docker35 ~]#
MySQL [(none)]> INSTALL PLUGIN group_replication SONAME 'group_replication.so';
Query OK, 0 rows affected (0.23 sec)
MySQL [(none)]> show plugins;
+---------------------------------+----------+--------------------+----------------------+---------+
| Name | Status | Type | Library | License |
+---------------------------------+----------+--------------------+----------------------+---------+
| group_replication | ACTIVE | GROUP REPLICATION | group_replication.so | GPL |
+---------------------------------+----------+--------------------+----------------------+---------+
45 rows in set (0.00 sec)
SET SQL_LOG_BIN=0;
CREATE USER repl@'%' IDENTIFIED BY 'lhr';
GRANT REPLICATION SLAVE ON *.* TO repl@'%';
FLUSH PRIVILEGES;
SET SQL_LOG_BIN=1;
CHANGE MASTER TO MASTER_USER='repl', MASTER_PASSWORD='lhr' FOR CHANNEL 'group_replication_recovery';
执行过程：
MySQL [(none)]> SET SQL_LOG_BIN=0;
Query OK, 0 rows affected (0.00 sec)
MySQL [(none)]> CREATE USER repl@'%' IDENTIFIED BY 'lhr';
Query OK, 0 rows affected (0.01 sec)
MySQL [(none)]> GRANT REPLICATION SLAVE ON *.* TO repl@'%';
Query OK, 0 rows affected (0.00 sec)
MySQL [(none)]> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.00 sec)
MySQL [(none)]> SET SQL_LOG_BIN=1;
Query OK, 0 rows affected (0.00 sec)
MySQL [(none)]> CHANGE MASTER TO MASTER_USER='repl', MASTER_PASSWORD='lhr' FOR CHANNEL 'group_replication_recovery';
Query OK, 0 rows affected, 1 warning (0.04 sec)
6.1、启动MGR，在主库(172.72.0.15)上执行
SET GLOBAL group_replication_bootstrap_group=ON;
START GROUP_REPLICATION;
SET GLOBAL group_replication_bootstrap_group=OFF;
-- 查看MGR组信息
SELECT * FROM performance_schema.replication_group_members;
执行过程：
MySQL [(none)]> SET GLOBAL group_replication_bootstrap_group=ON;
Query OK, 0 rows affected (0.00 sec)
MySQL [(none)]> START GROUP_REPLICATION;
Query OK, 0 rows affected (3.49 sec)
MySQL [(none)]> SET GLOBAL group_replication_bootstrap_group=OFF;
Query OK, 0 rows affected (0.00 sec)
MySQL [(none)]> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
| group_replication_applier | 611717fe-d785-11ea-9342-0242ac48000f | 172.72.0.15 | 3306 | ONLINE | PRIMARY | 8.0.20 |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
1 row in set (0.01 sec)
6.2、其他节点加入MGR，在从库（172.72.0.16，172.72.0.17）上执行
START GROUP_REPLICATION;
-- 查看MGR组信息
SELECT * FROM performance_schema.replication_group_members;
执行结果：
MySQL [(none)]> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
| group_replication_applier | 611717fe-d785-11ea-9342-0242ac48000f | 172.72.0.15 | 3306 | ONLINE | PRIMARY | 8.0.20 |
| group_replication_applier | 67090f47-d785-11ea-b76c-0242ac480010 | 172.72.0.16 | 3306 | ONLINE | SECONDARY | 8.0.20 |
| group_replication_applier | 678cf064-d785-11ea-b8ce-0242ac480011 | 172.72.0.17 | 3306 | ONLINE | SECONDARY | 8.0.20 |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
3 rows in set (0.01 sec)
可以看到，3个节点状态为online，并且主节点为172.72.0.15，只有主节点可以写入，其他节点只读，MGR单主模式搭建成功。
七、多主和单主模式切换7.1、查询当前模式
MySQL [(none)]> show variables like '%group_replication_single_primary_mode%';
+---------------------------------------+-------+
| Variable_name | Value |
+---------------------------------------+-------+
| group_replication_single_primary_mode | ON |
+---------------------------------------+-------+
1 row in set (0.01 sec)
MySQL [(none)]> SELECT @@group_replication_single_primary_mode;
+-----------------------------------------+
| @@group_replication_single_primary_mode |
+-----------------------------------------+
| 1 |
+-----------------------------------------+
1 row in set (0.00 sec)
参数group_replication_single_primary_mode为ON，表示单主模式。
7.2、函数实现多主和单主切换
函数切换：从MySQL 8.0.13开始，可以使用函数进行在线修改MGR模式。
-- 单主切多主
select group_replication_switch_to_multi_primary_mode();
-- 多主切单主，入参需要传入主库的server_uuid
select group_replication_switch_to_single_primary_mode('@@server_uuid') ;
-- 查看组信息
SELECT * FROM performance_schema.replication_group_members;
7.2.1、单主切多主模式
MySQL [(none)]> SELECT @@group_replication_single_primary_mode;
+-----------------------------------------+
| @@group_replication_single_primary_mode |
+-----------------------------------------+
| 1 |
+-----------------------------------------+
1 row in set (0.00 sec)
MySQL [(none)]> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
| group_replication_applier | 611717fe-d785-11ea-9342-0242ac48000f | 172.72.0.15 | 3306 | ONLINE | PRIMARY | 8.0.20 |
| group_replication_applier | 67090f47-d785-11ea-b76c-0242ac480010 | 172.72.0.16 | 3306 | ONLINE | SECONDARY | 8.0.20 |
| group_replication_applier | 678cf064-d785-11ea-b8ce-0242ac480011 | 172.72.0.17 | 3306 | ONLINE | SECONDARY | 8.0.20 |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
3 rows in set (0.00 sec)
MySQL [(none)]> select group_replication_switch_to_multi_primary_mode();
+--------------------------------------------------+
| group_replication_switch_to_multi_primary_mode() |
+--------------------------------------------------+
| Mode switched to multi-primary successfully. |
+--------------------------------------------------+
1 row in set (1.01 sec)
MySQL [(none)]> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
| group_replication_applier | 611717fe-d785-11ea-9342-0242ac48000f | 172.72.0.15 | 3306 | ONLINE | PRIMARY | 8.0.20 |
| group_replication_applier | 67090f47-d785-11ea-b76c-0242ac480010 | 172.72.0.16 | 3306 | ONLINE | PRIMARY | 8.0.20 |
| group_replication_applier | 678cf064-d785-11ea-b8ce-0242ac480011 | 172.72.0.17 | 3306 | ONLINE | PRIMARY | 8.0.20 |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
3 rows in set (0.00 sec)
MySQL [(none)]> SELECT @@group_replication_single_primary_mode;
+-----------------------------------------+
| @@group_replication_single_primary_mode |
+-----------------------------------------+
| 0 |
+-----------------------------------------+
7.2.2、多主切单主模式
MySQL [(none)]> SELECT @@group_replication_single_primary_mode;
+-----------------------------------------+
| @@group_replication_single_primary_mode |
+-----------------------------------------+
| 0 |
+-----------------------------------------+
1 row in set (0.00 sec)
MySQL [(none)]> select group_replication_switch_to_single_primary_mode('67090f47-d785-11ea-b76c-0242ac480010') ;
+-----------------------------------------------------------------------------------------+
| group_replication_switch_to_single_primary_mode('67090f47-d785-11ea-b76c-0242ac480010') |
+-----------------------------------------------------------------------------------------+
| Mode switched to single-primary successfully. |
+-----------------------------------------------------------------------------------------+
1 row in set (1.02 sec)
MySQL [(none)]> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
| group_replication_applier | 611717fe-d785-11ea-9342-0242ac48000f | 172.72.0.15 | 3306 | ONLINE | SECONDARY | 8.0.20 |
| group_replication_applier | 67090f47-d785-11ea-b76c-0242ac480010 | 172.72.0.16 | 3306 | ONLINE | PRIMARY | 8.0.20 |
| group_replication_applier | 678cf064-d785-11ea-b8ce-0242ac480011 | 172.72.0.17 | 3306 | ONLINE | SECONDARY | 8.0.20 |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
3 rows in set (0.00 sec)
MySQL [(none)]> SELECT @@group_replication_single_primary_mode;
+-----------------------------------------+
| @@group_replication_single_primary_mode |
+-----------------------------------------+
| 1 |
+-----------------------------------------+
1 row in set (0.00 sec)
7.3、手动切换
MGR切换模式需要重新启动组复制，因些需要在所有节点上先关闭组复制，设置 group_replication_single_primary_mode=OFF 等参数，再启动组复制。
7.3.1、单主切多主模式
1、停止组复制(所有节点执行)：
stop group_replication;
set global group_replication_single_primary_mode=OFF;
set global group_replication_enforce_update_everywhere_checks=ON;
2、随便选择某个节点执行
SET GLOBAL group_replication_bootstrap_group=ON;
START GROUP_REPLICATION;
SET GLOBAL group_replication_bootstrap_group=OFF;
3、其他节点执行
START GROUP_REPLICATION;
4、查看组信息，所有节点的 MEMBER_ROLE 都为 PRIMARY
MySQL [(none)]> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
| group_replication_applier | 611717fe-d785-11ea-9342-0242ac48000f | 172.72.0.15 | 3306 | ONLINE | PRIMARY | 8.0.20 |
| group_replication_applier | 67090f47-d785-11ea-b76c-0242ac480010 | 172.72.0.16 | 3306 | ONLINE | PRIMARY | 8.0.20 |
| group_replication_applier | 678cf064-d785-11ea-b8ce-0242ac480011 | 172.72.0.17 | 3306 | ONLINE | PRIMARY | 8.0.20 |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
3 rows in set (0.00 sec)
可以看到所有节点状态都是online，角色都是PRIMARY，MGR多主模式切换成功。
7.3.2、多主切单主模式
1、所有节点执行
stop group_replication;
set global group_replication_enforce_update_everywhere_checks=OFF;
set global group_replication_single_primary_mode=ON;
2、主节点（172.72.0.16）执行
SET GLOBAL group_replication_bootstrap_group=ON;
START GROUP_REPLICATION;
SET GLOBAL group_replication_bootstrap_group=OFF;
3、从节点（172.72.0.15、172.72.0.17）执行
START GROUP_REPLICATION;
4、查看MGR组信息
MySQL [(none)]> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
| group_replication_applier | 611717fe-d785-11ea-9342-0242ac48000f | 172.72.0.15 | 3306 | ONLINE | SECONDARY | 8.0.20 |
| group_replication_applier | 67090f47-d785-11ea-b76c-0242ac480010 | 172.72.0.16 | 3306 | ONLINE | PRIMARY | 8.0.20 |
| group_replication_applier | 678cf064-d785-11ea-b8ce-0242ac480011 | 172.72.0.17 | 3306 | ONLINE | SECONDARY | 8.0.20 |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
3 rows in set (0.00 sec)
在主节点上执行以下命令，然后在其它节点查询：
create database lhrdb;
CREATE TABLE lhrdb.`tb1` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`hostname` varchar(100) DEFAULT NULL,
`server_id` varchar(100) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
insert into lhrdb.tb1(hostname,server_id) select @@hostname,@@server_id;
select * from lhrdb.tb1;
-- 3个节点查询出来的值一样
MySQL [(none)]> select * from lhrdb.tb1;
+----+----------+-----------+
| id | hostname | server_id |
+----+----------+-----------+
| 1 | lhrmgr16 | 802033066 |
+----+----------+-----------+
1 row in set (0.02 sec)
9.1、创建新MySQL节点
mkdir -p /usr/local/mysql/lhrmgr18/conf.d
mkdir -p /usr/local/mysql/lhrmgr18/data
docker run -d --name mysql8020mgr33068 \
-h lhrmgr18 -p 33068:3306 --net=mysql-network --ip 172.72.0.18 \
-v /usr/local/mysql/lhrmgr18/conf.d:/etc/mysql/conf.d -v /usr/local/mysql/lhrmgr18/data:/var/lib/mysql/ \
-e MYSQL_ROOT_PASSWORD=lhr \
-e TZ=Asia/Shanghai \
mysql:8.0.20
cat > /usr/local/mysql/lhrmgr18/conf.d/my.cnf <<"EOF"
[mysqld]
user=mysql
port=3306
character_set_server=utf8mb4
secure_file_priv=''
server-id = 802033068
log-bin =
binlog_format=row
binlog_checksum=NONE
log-slave-updates=1
skip-name-resolve
auto-increment-increment=2
auto-increment-offset=1
gtid-mode=ON
enforce-gtid-consistency=on
default_authentication_plugin=mysql_native_password
max_allowed_packet = 500M
log_slave_updates=on
master_info_repository=TABLE
relay_log_info_repository=TABLE
relay_log=lhrmgr18-relay-bin-ip18
transaction_write_set_extraction=XXHASH64
loose-group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"
loose-group_replication_start_on_boot=OFF
loose-group_replication_local_address= "172.72.0.18:33064"
loose-group_replication_group_seeds= "172.72.0.15:33061,172.72.0.16:33062,172.72.0.17:33063,172.72.0.18:33064"
loose-group_replication_bootstrap_group=OFF
loose-group_replication_ip_whitelist="172.72.0.15,172.72.0.16,172.72.0.17,172.72.0.18"
report_host=172.72.0.18
report_port=3306
EOF
docker restart mysql8020mgr33068
docker ps
mysql -uroot -plhr -h192.168.1.35 -P33065 -e "select @@hostname,@@server_id,@@server_uuid"
mysql -uroot -plhr -h192.168.1.35 -P33066 -e "select @@hostname,@@server_id,@@server_uuid"
mysql -uroot -plhr -h192.168.1.35 -P33067 -e "select @@hostname,@@server_id,@@server_uuid"
mysql -uroot -plhr -h192.168.1.35 -P33068 -e "select @@hostname,@@server_id,@@server_uuid"
mysql -uroot -plhr -h192.168.1.35 -P33065
mysql -uroot -plhr -h192.168.1.35 -P33066
mysql -uroot -plhr -h192.168.1.35 -P33067
mysql -uroot -plhr -h192.168.1.35 -P33068
docker logs -f --tail 10 mysql8020mgr33065
docker logs -f --tail 10 mysql8020mgr33066
docker logs -f --tail 10 mysql8020mgr33067
docker logs -f --tail 10 mysql8020mgr33068
9.2、新节点安装MGR插件
-- 安装MGR插件（新增节点执行）
INSTALL PLUGIN group_replication SONAME 'group_replication.so';
show plugins;
9.3、新节点设置复制账号
-- 设置复制账号（新增节点执行）
SET SQL_LOG_BIN=0;
CREATE USER repl@'%' IDENTIFIED BY 'lhr';
GRANT REPLICATION SLAVE ON *.* TO repl@'%';
FLUSH PRIVILEGES;
SET SQL_LOG_BIN=1;
CHANGE MASTER TO MASTER_USER='repl', MASTER_PASSWORD='lhr' FOR CHANNEL 'group_replication_recovery';
9.4、在原3节点执行修改参数
set global group_replication_group_seeds='172.72.0.15:33061,172.72.0.16:33062,172.72.0.17:33063,172.72.0.18:33064';
stop group_replication;
set global group_replication_ip_whitelist="172.72.0.15,172.72.0.16,172.72.0.17,172.72.0.18";
start group_replication;
9.5、新节点加入
-- 4个节点需要保证以下2个参数的值一致
MySQL [(none)]> select @@group_replication_enforce_update_everywhere_checks,@@group_replication_single_primary_mode;
+------------------------------------------------------+-----------------------------------------+
| @@group_replication_enforce_update_everywhere_checks | @@group_replication_single_primary_mode |
+------------------------------------------------------+-----------------------------------------+
| 0 | 1 |
+------------------------------------------------------+-----------------------------------------+
-- 如果不一致，那么需要修改
set global group_replication_single_primary_mode=ON;
set global group_replication_enforce_update_everywhere_checks=OFF;
CHANGE MASTER TO MASTER_USER='repl', MASTER_PASSWORD='lhr' FOR CHANNEL 'group_replication_recovery';
-- 新节点加入
start group_replication;
9.6、查看所有节点
MySQL [lhrdb]> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
| group_replication_applier | 611717fe-d785-11ea-9342-0242ac48000f | 172.72.0.15 | 3306 | ONLINE | PRIMARY | 8.0.20 |
| group_replication_applier | 67090f47-d785-11ea-b76c-0242ac480010 | 172.72.0.16 | 3306 | ONLINE | SECONDARY | 8.0.20 |
| group_replication_applier | 678cf064-d785-11ea-b8ce-0242ac480011 | 172.72.0.17 | 3306 | ONLINE | SECONDARY | 8.0.20 |
| group_replication_applier | e4d6bf4b-d78d-11ea-b1b6-0242ac480012 | 172.72.0.18 | 3306 | ONLINE | SECONDARY | 8.0.20 |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
4 rows in set (0.31 sec)
如果需要重置，那么需要执行如下命令：
STOP GROUP_REPLICATION;
reset master;
SET SQL_LOG_BIN=1;
CHANGE MASTER TO MASTER_USER='repl', MASTER_PASSWORD='lhr' FOR CHANNEL 'group_replication_recovery';
start GROUP_REPLICATION;
