MySQL Group Replication-现有普通复制集群提升为Group Replication

上一篇测试了各种场景下，向Group Replication中添加新节点。那么，如果原来有一套master-slave集群，需要怎么把它改造成Group Replication集群呢？

Group Replication是基于GTID来复制的，那么第一步就是需要将普通复制改造成GTID复制。有了GTID那么将Master-Slave结构改造成Group Replication就很方便了。

搭建普通复制环境

解压安装包

[root@mser02 local]# tar -zxvf mysql-5.7.15-labs-gr090-linux-glibc2.5-x86_64.tar.gz

[root@mser02 local]# mv mysql-5.7.15-labs-gr090-linux-glibc2.5-x86_64 mysql5.7

[root@mser02 local]# cd mysql5.7/

初始化数据

[server01]

./bin/mysqld --no-defaults --user=mysql --initialize --explicit_defaults_for_timestamp --basedir=/usr/local/mysql5.7/ --datadir=/usr/local/mysql5.7/data_1

[server02]

./bin/mysqld --no-defaults --user=mysql --initialize --explicit_defaults_for_timestamp --basedir=/usr/local/mysql5.7/ --datadir=/usr/local/mysql5.7/data_2

[server03]

./bin/mysqld --no-defaults --user=mysql --initialize --explicit_defaults_for_timestamp --basedir=/usr/local/mysql5.7/ --datadir=/usr/local/mysql5.7/data_3

编辑配置文件

[server1]

my_1.cnf

[mysqld]
server-id = 1
basedir=/usr/local/mysql5.7/
datadir=/usr/local/mysql5.7/data_1
user=mysql
explicit_defaults_for_timestamp
socket=mysql1.sock
port = 3306

# binlog
log-bin=mysql-bin
binlog-format = ROW
log-slave-updates = ON
master-info-repository = TABLE
relay-log-info-repository = TABLE
binlog-checksum = NONE
slave-parallel-workers = 0

[server2]

my_2.cnf

[mysqld]
server-id = 2
basedir=/usr/local/mysql5.7/
datadir=/usr/local/mysql5.7/data_2
user=mysql
explicit_defaults_for_timestamp
socket=mysql2.sock
port = 3307

# binlog
log-bin=mysql-bin
binlog-format = ROW
log-slave-updates = ON
master-info-repository = TABLE
relay-log-info-repository = TABLE
binlog-checksum = NONE
slave-parallel-workers = 0

[server3]

my_3.cnf

[mysqld]
server-id = 3
basedir=/usr/local/mysql5.7/
datadir=/usr/local/mysql5.7/data_3
user=mysql
explicit_defaults_for_timestamp
socket=mysql3.sock
port = 3308

# binlog
log-bin=mysql-bin
binlog-format = ROW
log-slave-updates = ON
master-info-repository = TABLE
relay-log-info-repository = TABLE
binlog-checksum = NONE
slave-parallel-workers = 0

mysql> CREATE USER rpl_user@'%';
Query OK, 0 rows affected (0.03 sec)

mysql> GRANT REPLICATION SLAVE ON *.* TO rpl_user@'%' IDENTIFIED BY 'rpl_pass';
Query OK, 0 rows affected, 1 warning (0.00 sec)

启动mysql

[server01]

./bin/mysqld --defaults-file=/usr/local/mysql5.7/my_1.cnf

[server02]

./bin/mysqld --defaults-file=/usr/local/mysql5.7/my_2.cnf

[server03]

./bin/mysqld --defaults-file=/usr/local/mysql5.7/my_3.cnf

修改初始密码

[server01]

./bin/mysqladmin -u root -h 127.0.0.1 -P 3306 -p password "111111"

[server02]

./bin/mysqladmin -u root -h 127.0.0.1 -P 3307 -p password "111111"

[server03]

./bin/mysqladmin -u root -h 127.0.0.1 -P 3308 -p password "111111"

组建集群

首先在[server01]中进行如下配置：

CREATE USER rpl_user@'%';
GRANT REPLICATION SLAVE ON *.* TO rpl_user@'%' IDENTIFIED BY 'rpl_pass';
FLUSH PRIVILEGES;

再在其他两个节点执行如下命令

mysql> change master to master_host='127.0.0.1',master_port=3306,master_user='rpl_user',master_password='rpl_pass',master_log_file='mysql-bin.000001',master_log_pos=386;
Query OK, 0 rows affected, 2 warnings (0.14 sec)

mysql> start slave;
Query OK, 0 rows affected (0.01 sec)

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 127.0.0.1
                  Master_User: rpl_user
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000001
          Read_Master_Log_Pos: 859
               Relay_Log_File: mser01-relay-bin.000002
                Relay_Log_Pos: 785
        Relay_Master_Log_File: mysql-bin.000001
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes

这样普通Master-Slave结构就完成了

进行测试

Master节点上执行

mysql> create database bobo;
Query OK, 1 row affected (0.01 sec)

mysql> use bobo;
Database changed
mysql> create table test1 (id int primary key,name varchar(20));
Query OK, 0 rows affected (0.19 sec)

mysql> insert into test1(id,name) values (1,'aaaa');
Query OK, 1 row affected (0.03 sec)

mysql> insert into test1(id,name) values (2,'bbbb');
Query OK, 1 row affected (0.05 sec)

mysql> insert into test1(id,name) values (3,'cccc');
Query OK, 1 row affected (0.03 sec)

mysql> insert into test1(id,name) values (4,'dddd');
Query OK, 1 row affected (0.03 sec)

mysql> select * from test1;
+----+------+
| id | name |
+----+------+
|  1 | aaaa |
|  2 | bbbb |
|  3 | cccc |
|  4 | dddd |
+----+------+
4 rows in set (0.00 sec)

Slave节点执行

mysql> use bobo;
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> select * from test1;
+----+------+
| id | name |
+----+------+
|  1 | aaaa |
|  2 | bbbb |
|  3 | cccc |
|  4 | dddd |
+----+------+
4 rows in set (0.00 sec)

转换成GTID复制

MySQL 5.7.6以后的版本可以在线进行GTID的切换，但是要保证所有组中成员gtid_mode 为off状态。

实现步骤：

所有的Server执行

set @@global.enforce_gtid_consistency = warn;

特别注意： 这一步是关建的一步使用不能出现警告。

所有的server上执行：

set @@global.enforce_gtid_consistency = on;

所有的Server上执行（不关心最先最后，但要执行完）：

set @@global.gtid_mode = off_permissive;

执行：

set @@global.gtid_mode=on_permissive;

实质在这一步骤生的日志都是带GTID的日志了，这个步骤号称是不关心任何节点，但从实管理上推荐在slave上先执行，然后再去master上执行。

确认传统的binlog复制完毕,该值为0

show status like ‘ongoing_anonymous_transaction_count’;

需要所有的节点都确认为0.

所有节点进行判断

show status like ‘ongoing_anonymous_transaction_count’;

为零
所有的节点也可以执行一下: flush logs; 用于切换一下日志。

所有的节点启用gtid_mode

set @@global.gtid_mode=on

把gtid_mode = on相关配置写入配置文件

gtid_mode=on

enforce_gtid_consistency=on

启用Gtid的自动查找节点复制：

stop slave;

change master to master_auto_position=1;

start slave;

这样普通的Master-Slave就在线的切换成了基于GTID复制了。

注：能够进行在线的GTID的切换，得益于mysql5.7.6以后的版本中，gtid_mode出现了两个新的状态OFF_PERMISSIVE、ON_PERMISSIVE，以及enforce_gtid_consistency中新增Warn状态

enforce_gtid_consistency

Warn ：当检测到不支持GTID的语句和事务，返回警告，并在日志中记录

gtid_mode

• OFF_PERMISSIVE: New transactions are anonymous. Replicated transactions can be eitheranonymous or GTID transactions.

• ON_PERMISSIVE: New transactions are GTID transactions. Replicated transactions can be either anonymous or GTID transactions.

• OFF_PERMISSIVE ：不产生GTID，Slave即接受不带GTID的事务，也接受带GTID的事务

• ON_PERMISSIVE ：产生GTID，Slave即接受不带GTID的事务，也接受带GTID的事务

有了不支持GTID事务的检查功能，也有了即支持GTID复制也支持普通复制的过度状态，这样就可以在线平滑的将Master-Slave普通复制切换成GTID复制。
此步骤参考：
http://wubx.net/mysql-5-7-class-repl-online-2-gtid-repl/

开启Group Replication

修改成GTID模式之后，接下来切换成Group Replication就方便了。

安装Group Replicaiton插件

在全部server上执行

mysql> INSTALL PLUGIN group_replication SONAME 'group_replication.so';
Query OK, 0 rows affected (0.03 sec)


mysql> show plugins;
+----------------------------+----------+--------------------+----------------------+---------+
| Name                       | Status   | Type               | Library              | License |
+----------------------------+----------+--------------------+----------------------+---------+
| binlog                     | ACTIVE   | STORAGE ENGINE     | NULL                 | GPL     |
…………
| group_replication          | ACTIVE   | GROUP REPLICATION  | group_replication.so | GPL     |
+----------------------------+----------+--------------------+----------------------+---------+
45 rows in set (0.00 sec)

配置参数

[server1]

mysql> set @@global.transaction_write_set_extraction = XXHASH64
mysql> set @@global.group_replication_start_on_boot = OFF
mysql> set @@global.group_replication_bootstrap_group = OFF 
mysql> set @@global.group_replication_group_name = 0c6d3e5f-90e2-11e6-802e-842b2b5909d6
mysql> set @@global.group_replication_local_address = '127.0.0.1:6606'
mysql> set @@global.group_replication_group_seeds = '127.0.0.1:6607,127.0.0.1:6608'

[server2]

mysql> set @@global.transaction_write_set_extraction = XXHASH64
mysql> set @@global.group_replication_start_on_boot = OFF
mysql> set @@global.group_replication_bootstrap_group = OFF 
mysql> set @@global.group_replication_group_name = 0c6d3e5f-90e2-11e6-802e-842b2b5909d6
mysql> set @@global.group_replication_local_address = '127.0.0.1:6607'
mysql> set @@global.group_replication_group_seeds = '127.0.0.1:6606,127.0.0.1:6608'

[server3]

mysql> set @@global.transaction_write_set_extraction = XXHASH64
mysql> set @@global.group_replication_start_on_boot = OFF
mysql> set @@global.group_replication_bootstrap_group = OFF 
mysql> set @@global.group_replication_group_name = 0c6d3e5f-90e2-11e6-802e-842b2b5909d6
mysql> set @@global.group_replication_local_address = '127.0.0.1:6608'
mysql> set @@global.group_replication_group_seeds = '127.0.0.1:6607,127.0.0.1:6606'

==特别注意==：如果之前没有配置transaction_write_set_extraction=XXHASH64，这里修改之后之前创建的数据库是没有办法执行插入操作的。所有如果想在线完成Group Replication的改造需要保证之前已经设置了transaction_write_set_extraction=XXHASH64。

构建集群

[server1]

CHANGE MASTER TO MASTER_USER='rpl_user', MASTER_PASSWORD='rpl_pass' FOR CHANNEL 'group_replication_recovery';

注：在普通Master-Slave中已经配置过复制用户了，所以在构建Group Replicaiton时不需要再重新创建了。

开启group_replication

SET GLOBAL group_replication_bootstrap_group=ON;
START GROUP_REPLICATION;
SET GLOBAL group_replication_bootstrap_group=OFF;

其他节点加入group_replication集群

stop slave;
START GROUP_REPLICATION;

在查看节点信息

mysql> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+-------------+-------------+--------------+
| CHANNEL_NAME              | MEMBER_ID                            | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE |
+---------------------------+--------------------------------------+-------------+-------------+--------------+
| group_replication_applier | 0aab37dc-911c-11e6-ab03-842b2b5909d6 | mser01      |        3308 | ONLINE       |
| group_replication_applier | a876d35e-9110-11e6-a365-842b2b5909d6 | mser01      |        3306 | ONLINE       |
| group_replication_applier | b34df071-911a-11e6-9796-842b2b5909d6 | mser01      |        3307 | ONLINE       |
+---------------------------+--------------------------------------+-------------+-------------+--------------+
3 rows in set (0.00 sec)

这样普通Master-Slave集群改造成Group Replication集群就完成了。