MySQL MGR--MGR部署

MGR部署

場景描述：

使用三台服務器搭建一個簡單MGR集群，使用MySQL 5.7.24版本，服務器列表為：

192.168.1.147
192.168.1.148
192.168.1.149

 

1、使用普通配置文件啟動MySQL服務，安裝MGR插件(所有節點執行)

INSTALL PLUGIN group_replication SONAME 'group_replication.so';

 

2、調整MySQL各節點的配置文件並重啟MySQL服務(所有節點執行)

## config master
server-id               				= 17218228149
log-bin                 				= mysql-bin
master_info_repository  				= TABLE
binlog_format           				= ROW
expire_logs_days        				= 7
sync_binlog             				= 1
gtid_mode                				= on
enforce-gtid-consistency 				= true
binlog_rows_query_log_events 			        = on
binlog_checksum　　　　　　　　　　　　　　　　　　　　　　　　 = NONE


## config slave
skip-slave-start
slave-parallel-workers  				= 8
slave-parallel-type 					= LOGICAL_CLOCK
slave_preserve_commit_order 			        = 1
log_slave_updates      					= 1
report_host						= 192.168.1.149


## config relay log
relay-log               				= relay-log
relay_log_recovery      				= ON
sync_relay_log          				= 0
relay_log_info_repository 				= TABLE


## config group replication
transaction_write_set_extraction		　　　= XXHASH64
loose-group_replication_group_name	 	　　　= "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaa01"
loose-group_replication_start_on_boot	　　　　　　　　= OFF
loose-group_replication_bootstrap_group	　　　　　　　　= OFF
loose-group_replication_local_address	　　　　　　　　= "192.168.1.149:33581"
loose-group_replication_group_seeds		　　　= "192.168.1.147:33581,192.168.1.148:33581,192.168.1.149:33581"
loose-group_replication_ip_whitelist	　　　　　　　 = "192.168.1.147,192.168.1.148,192.168.1.149"

未安裝MGR插件前在配置文件加入MGR配置會報錯。

MGR配置說明：上面黃色部分參數在很多配置文件中都沒提到，但很可能會導致部署失敗，尤其是loose-group_replication_ip_whitelist參數。

 

3、配置MGR通信賬號，並清理MASTER(所有節點執行)

CREATE USER repl@'%' IDENTIFIED BY 'repl';
GRANT REPLICATION SLAVE ON *.* TO repl@'%';
RESET MASTER;

 

4、創建MGR依賴的復制環境(所有節點執行)

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

 

5、在主節點上啟動MGR(在節點192.168.1.147上執行)

SET GLOBAL group_replication_bootstrap_group=ON;
START group_replication;
SET GLOBAL group_replication_bootstrap_group=off;

 

6、在輔助節點上啟動MGR(在節點192.168.1.148和在節點192.168.1.149上執行)

START group_replication;

 

7、搭建完成后，可以使用下面語句查看狀態：

## 查看各節點狀態
SELECT * 
FROM performance_schema.replication_group_members;

## 查看當前MGR模式(單主還是多主)
SELECT @@group_replication_single_primary_mode;

 

8、判斷節點狀態

## 查看當前節點狀態
SELECT member_state 
FROM performance_schema.replication_group_members 
WHERE member_id=@@server_uuid;


## 通過節點是否可寫來判斷群集是否為主節點
SELECT * 
FROM performance_schema.global_variables 
WHERE variable_name IN ('read_only', 'super_read_only');

MGR成員的五種狀態：

ONLINE: The member is in a fully functioning state.

RECOVERING: The server has joined a group from which it is retrieving data.

OFFLINE: The group replication plugin is installed but has not been started.

ERROR: The member has encountered an error, either during applying transactions or during the recovery phase, and is not participating in the group's transactions.

UNREACHABLE: The failure detection process suspects that this member cannot be contacted, because the group messages have timed out.

 

新增MGR節點

目前MySQL不支持自動擴展新節點並將全量數據同步到新節點，因此需要：

1、備份任一節點數據(MySQLDump或Xtrabackup)至新節點並還原

2、在新節點上設置與備份數據對應的Executed_Gtid_Set

3、在新節點上執行下面命令直接啟動MGR復制即可。

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

START GROUP_REPLICATION;