MGR集群搭建及配置過程
MGR全稱MySQL Group Replication（Mysql組復制），是MySQL官方於2016年12月推出的一個全新的高可用與高擴展的解決方案。MGR提供瞭高可用、高擴展、高可靠的MySQL集群服務。在MGR出現之前，用戶常見的MySQL高可用方式，無論怎麼變化架構，本質就是Master-Slave架構。MySQL 5.7版本開始支持無損半同步復制（lossless semi-sync replication），從而進一步提示數據復制的強一致性。
MGR是MySQL數據庫未來發展的一個重要方向。
註意：根據本人測試group_replication.so插件是mysql-community-server安裝包中攜帶，如果是rpm安裝或yum安裝存放地址為/usr/lib64/mysql/plugin/目錄下，看下圖。另外在安裝5.7.16版本時是沒有這個插件，而在安裝5.7.20版本有這個插件，推測這是一個5.7.16到5.7.20之間新加的插件，個人建議安裝5.7.20以上的版本。另外大傢請在安裝好mysql後查看一下是否存在這個插件。
如果提示group_replication.so不存在，或提示有問題並且查看時發現group_replication.so不存在，請重點看一下mysql的版本。（我搜瞭一大圈，沒有一個人說這個問題。表示懷疑自己，如果我錯瞭，請留言。）
(1).MGR的特性
高一致性。基於原生復制及paxos協議的組復制技術，並以插件的方式提供，提供一致數據安全保證；
高容錯性。隻要不是大多數節點壞掉就可以繼續工作，有自動檢測機制，當不同節點產生資源爭用沖突時，不會出現錯誤，按照先到者優先原則進行處理，並且內置瞭自動化腦裂防護機制；
高擴展性。節點的新增和移除都是自動的，新節點加入後，會自動從其他節點上同步狀態，直到新節點和其他節點保持一致，如果某節點被移除瞭，其他節點自動更新組信息，自動維護新的組信息；
高靈活性。有單主模式和多主模式，單主模式下，會自動選主，所有更新操作都在主上進行；多主模式下，所有server都可以同時處理更新操作。
(2).搭建MGR的基礎結構要求和使用限制（重點）
基礎結構要求：1.引擎必須為innodb,因為需事務支持在commit時對各節點進行沖突檢查；2.每個表必須有主鍵，在進行事務沖突檢測時需要利用主鍵值對比；3.必須開啟binlog且為row格式；4.開啟GTID，且主從狀態信息存於表中（–master-info-repository=TABLE 、–relay-log-info-repository=TABLE），–log-slave-updates打開；5.一致性檢測設置–transaction-write-set-extraction=XXHASH64。
使用限制：1.RP和普通復制binlog校驗不能共存，需設置–binlog-checksum=none；2.不支持gap lock(間隙鎖)，隔離級別需設置為read_committed；3.不支持對表進行鎖操作（lock /unlock table）,不會發送到其他節點執行 ,影響需要對表進行加鎖操作的情況，列入mysqldump全表備份恢復操作；4.不支持serializable(序列化)隔離級別；5.DDL語句不支持原子性，不能檢測沖突，執行後需自行校驗是否一；6.多主模式下不支持外鍵，單主模式下支持外鍵；最多9個節點，超過9臺無法加入集群
(3).實驗環境
youxi1 192.168.1.6 CentOS7.6 Mysql5.7.26 端口號3306 server-id=1
youxi2 192.168.1.7 CentOS7.6 Mysql5.7.26 端口號3306 server-id=2
youxi3 192.168.1.8 CentOS7.6 Mysql5.7.26 端口號3306 server-id=3
另外，三臺服務器上都進行IP的映射（如果此處不映射，請修改/etc/my.cnf配置文件中對應的域名為IP地址）
[root@youxi1 ~]# vim /etc/hosts 192.168.1.6 youxi1.cn youxi1 //長域名和短域名隻要映射一個即可 192.168.1.7 youxi2.cn youxi2 192.168.1.8 youxi3.cn youxi3
(1).單主模式
我是在空數據庫下操作，如果主數據集已存在數據，需要將主數據庫的數據導出再導入到從數據庫。另外還需保證引擎為innodb，每個表必須存在主鍵。
1）以youxi1作為主服務器，對youxi1進行配置
創建一個復制用的用戶
mysql> grant replication slave on *.* to 'repl'@'192.168.1.%' identified by '12345678'; Query OK, 0 rows affected, 1 warning (0.01 sec) mysql> flush privileges; Query OK, 0 rows affected (0.00 sec)
修改配置文件，加入到[mysqld]模塊下。然後重啟mysqld
[root@youxi1 ~]# vim /etc/my.cnf server-id=1 //Mysql服務ID gtid-mode=on //全局事務 enforce-gtid-consistency=on //強制GTID的一致性 master-info-repository=TABLE //將master.info元數據保存在系統表中 relay-log-info-repository=TABLE //將relay.info元數據保存在系統表中 binlog-checksum=none //禁用二進制日志事件校驗 log-slave-updates=on //級聯復制 log-bin=binlog //開啟二進制日志記錄 binlog-format=ROW //以行的格式記錄 transaction-write-set-extraction=XXHASH64 //使用哈希算法將其編碼為散列 loose-group_replication_group_name='ce9be252-2b71-11e6-b8f4-00212844f856' //加入的組名，可以修改，隻要格式對 loose-group_replication_start_on_boot=off //不自動啟用組復制集群 loose-group_replication_local_address='youxi1:33061' //以本機端口33061接受來自組中成員的傳入連接 loose-group_replication_group_seeds='youxi1:33061,youxi2:33062,youxi3:33063' //組中成員訪問表 loose-group_replication_bootstrap_group=off //不啟用引導組 [root@youxi1 ~]# systemctl restart mysqld
註意：如果防火墻是打開的，記得添加mysql的端口號。
[root@youxi1 ~]# firewall-cmd --permanent --zone=public --add-port={3306,33061}/tcp
success
[root@youxi1 ~]# firewall-cmd --reload
success
[root@youxi1 ~]# firewall-cmd --zone=public --list-ports
3306/tcp 33061/tcp
修改master信息，構建組復制（group replication）集群信息
mysql> change master to master_user='repl',master_password='12345678' for channel 'group_replication_recovery'; Query OK, 0 rows affected, 2 warnings (0.04 sec)
安裝組復制（group replication）插件，並查看組件信息
mysql> install PLUGIN group_replication SONAME 'group_replication.so'; Query OK, 0 rows affected (0.21 sec) mysql> show plugins; //查看組件是否安裝成功 +----------------------------+----------+--------------------+----------------------+---------+ | 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 | DISABLED | VALIDATE PASSWORD | validate_password.so | GPL | | group_replication | ACTIVE | GROUP REPLICATION | group_replication.so | GPL | +----------------------------+----------+--------------------+----------------------+---------+ 46 rows in set (0.00 sec)
作為主服務器需要由這臺服務器開啟引導，開啟組復制（group replication）集群
mysql> set global group_replication_bootstrap_group=on; //開啟組復制引導 Query OK, 0 rows affected (0.00 sec) mysql> start group_replication; //開啟組復制 Query OK, 0 rows affected (2.24 sec) mysql> set global group_replication_bootstrap_group=off; //關閉組復制引導 Query OK, 0 rows affected (0.00 sec)
查看到添加到組復制集群的服務器信息
mysql> select * from performance_schema.replication_group_members; +---------------------------+--------------------------------------+-------------+-------------+--------------+ | CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | +---------------------------+--------------------------------------+-------------+-------------+--------------+ | group_replication_applier | c9e3662b-9020-11e9-94aa-000c29721e89 | youxi1 | 3306 | ONLINE | +---------------------------+--------------------------------------+-------------+-------------+--------------+ 1 row in set (0.00 sec)
2）對youxi2進行配置
創建一個復制用的用戶
mysql> grant replication slave on *.* to 'repl'@'192.168.1.%' identified by '12345678'; Query OK, 0 rows affected, 1 warning (0.01 sec) mysql> flush privileges; Query OK, 0 rows affected (0.01 sec)
修改配置文件，加入到[mysqld]模塊下。然後重啟mysqld
[root@youxi2 ~]# vim /etc/my.cnf server-id=2 //修改 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='youxi2:33062' //修改 loose-group_replication_group_seeds='youxi1:33061,youxi2:33062,youxi3:33063' loose-group_replication_bootstrap_group=off [root@youxi2 ~]# systemctl restart mysqld
註意：如果防火墻是打開的，記得添加mysql的端口號。
[root@youxi2 ~]# firewall-cmd --permanent --zone=public --add-port={3306,33062}/tcp
success
[root@youxi2 ~]# firewall-cmd --reload
success
[root@youxi2 ~]# firewall-cmd --zone=public --list-ports
3306/tcp 33062/tcp
修改master信息，構建組復制（group replication）集群信息
mysql> change master to master_user='repl',master_password='12345678' for channel 'group_replication_recovery'; Query OK, 0 rows affected, 2 warnings (0.05 sec)
安裝組復制（group replication）插件
mysql> install PLUGIN group_replication SONAME 'group_replication.so'; Query OK, 0 rows affected (0.35 sec)
把youxi2加到之前的組復制（group replication）
mysql> set global group_replication_allow_local_disjoint_gtids_join=ON; Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> start group_replication; Query OK, 0 rows affected, 1 warning (5.92 sec)
查看到添加到組復制集群的服務器信息
mysql> select * from performance_schema.replication_group_members; +---------------------------+--------------------------------------+-------------+-------------+--------------+ | CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | +---------------------------+--------------------------------------+-------------+-------------+--------------+ | group_replication_applier | 8fbf8b41-84fe-11e9-897e-000c29f27e52 | youxi2 | 3306 | ONLINE | | group_replication_applier | c9e3662b-9020-11e9-94aa-000c29721e89 | youxi1 | 3306 | ONLINE | +---------------------------+--------------------------------------+-------------+-------------+--------------+ 2 rows in set (0.00 sec)
3）youxi3的配置與youxi2的配置幾乎一樣，隻需在/etc/my.cnf修改server-id和loose-group_replication_local_address即可。
查看一下組復制集群信息
mysql> select * from performance_schema.replication_group_members; +---------------------------+--------------------------------------+-------------+-------------+--------------+ | CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | +---------------------------+--------------------------------------+-------------+-------------+--------------+ | group_replication_applier | 74df3399-91b8-11e9-be5f-000c299fdf40 | youxi3 | 3306 | ONLINE | | group_replication_applier | 8fbf8b41-84fe-11e9-897e-000c29f27e52 | youxi2 | 3306 | ONLINE | | group_replication_applier | c9e3662b-9020-11e9-94aa-000c29721e89 | youxi1 | 3306 | ONLINE | +---------------------------+--------------------------------------+-------------+-------------+--------------+ 3 rows in set (0.01 sec)
註意：如果防火墻是打開的，記得添加mysql的端口號。
[root@youxi3 ~]# firewall-cmd --permanent --zone=public --add-port=3306/tcp success [root@youxi3 ~]# firewall-cmd --permanent --zone=public --add-port=33063/tcp success [root@youxi3 ~]# firewall-cmd --reload success [root@youxi3 ~]# firewall-cmd --zone=public --list-ports 3306/tcp 33063/tcp
4）測試
在youxi1上創建數據
mysql> create database test_db; Query OK, 1 row affected (0.00 sec) mysql> use test_db; Database changed mysql> create table user_tb(id int key,name varchar(20)); //id是主鍵，引擎默認是innodb Query OK, 0 rows affected (0.02 sec) mysql> insert into user_tb values(1,'zhangsan'); Query OK, 1 row affected (0.08 sec)
在youxi2上查看
mysql> select * from test_db.user_tb; +----+----------+ | id | name | +----+----------+ | 1 | zhangsan | +----+----------+ 1 row in set (0.00 sec)
在youxi3上查看
mysql> select * from test_db.user_tb; +----+----------+ | id | name | +----+----------+ | 1 | zhangsan | +----+----------+ 1 row in set (0.00 sec)
5）那麼怎麼區分主從服務器
MGR區分主從服務器使用show variables like '%read_only%';查看read_only相關參數。如果是主服務器（youxi1），會顯示如下：
mysql> show variables like '%read_only%'; +-----------------------+-------+ | Variable_name | Value | +-----------------------+-------+ | innodb_read_only | OFF | | read_only | OFF | | super_read_only | OFF | | transaction_read_only | OFF | | tx_read_only | OFF | +-----------------------+-------+ 5 rows in set (0.00 sec)
如果是從服務器（youxi2）會顯示如下：
mysql> show variables like '%read_only%'; +-----------------------+-------+ | Variable_name | Value | +-----------------------+-------+ | innodb_read_only | OFF | | read_only | ON | | super_read_only | ON | | transaction_read_only | OFF | | tx_read_only | OFF | +-----------------------+-------+ 5 rows in set (0.01 sec)
6）查看當前服務器的組復制集群參數設置列表
mysql> show variables like 'group_replication%'; +----------------------------------------------------+----------------------------------------+ | Variable_name | Value | +----------------------------------------------------+----------------------------------------+ | group_replication_allow_local_disjoint_gtids_join | OFF | | group_replication_allow_local_lower_version_join | OFF | | group_replication_auto_increment_increment | 7 | | group_replication_bootstrap_group | OFF | | group_replication_components_stop_timeout | 31536000 | | group_replication_compression_threshold | 1000000 | | group_replication_enforce_update_everywhere_checks | OFF | | group_replication_exit_state_action | READ_ONLY | | group_replication_flow_control_applier_threshold | 25000 | | group_replication_flow_control_certifier_threshold | 25000 | | group_replication_flow_control_mode | QUOTA | | group_replication_force_members | | | group_replication_group_name | ce9be252-2b71-11e6-b8f4-00212844f856 | | group_replication_group_seeds | youxi1:33061,youxi2:33062,youxi3:33063 | | group_replication_gtid_assignment_block_size | 1000000 | | group_replication_ip_whitelist | AUTOMATIC | | group_replication_local_address | youxi1:33061 | | group_replication_member_weight | 50 | | group_replication_poll_spin_loops | 0 | | group_replication_recovery_complete_at | TRANSACTIONS_APPLIED | | group_replication_recovery_reconnect_interval | 60 | | group_replication_recovery_retry_count | 10 | | group_replication_recovery_ssl_ca | | | group_replication_recovery_ssl_capath | | | group_replication_recovery_ssl_cert | | | group_replication_recovery_ssl_cipher | | | group_replication_recovery_ssl_crl | | | group_replication_recovery_ssl_crlpath | | | group_replication_recovery_ssl_key | | | group_replication_recovery_ssl_verify_server_cert | OFF | | group_replication_recovery_use_ssl | OFF | | group_replication_single_primary_mode | ON | | group_replication_ssl_mode | DISABLED | | group_replication_start_on_boot | OFF | | group_replication_transaction_size_limit | 0 | | group_replication_unreachable_majority_timeout | 0 | +----------------------------------------------------+----------------------------------------+ 36 rows in set (0.00 sec)
7）如果主服務器出問題，MGR會自動切換主服務器
將youxi1的mysqld人為關閉
[root@youxi1 ~]# systemctl stop mysqld
之後前往youxi2和youxi3查看誰是主服務器
mysql> show variables like '%read_only%'; //這是youxi2的 +-----------------------+-------+ | Variable_name | Value | +-----------------------+-------+ | innodb_read_only | OFF | | read_only | ON | | super_read_only | ON | | transaction_read_only | OFF | | tx_read_only | OFF | +-----------------------+-------+ 5 rows in set (0.01 sec) mysql> show variables like '%read_only%'; //這是youxi3的 +-----------------------+-------+ | Variable_name | Value | +-----------------------+-------+ | innodb_read_only | OFF | | read_only | OFF | | super_read_only | OFF | | transaction_read_only | OFF | | tx_read_only | OFF | +-----------------------+-------+ 5 rows in set (0.02 sec)
可以看到youxi3變成瞭主服務器，那麼嘗試在youxi3中插入數據
mysql> insert into test_db.user_tb values(2,'lisi'); Query OK, 1 row affected (0.14 sec)
再到youxi2中查看數據
mysql> select * from test_db.user_tb; +----+----------+ | id | name | +----+----------+ | 1 | zhangsan | | 2 | lisi | +----+----------+ 2 rows in set (0.00 sec)
(2).多主模式
1）在創建時就啟用多主模式
在創建時就啟用多主模式隻需在修改配置文件/etc/my.cnf時多加兩行參數。其餘保持不變
loose-group_replication_single_primary_mode=off //關閉單master模式 loose-group_replication_enforce_update_everywhere_checks=ON //多主一致性檢查
2）由單主模式改為多主模式
由單主改為多主時，一樣需要所有服務器配置信息增加兩行參數，為瞭下次開啟就是多主模式
loose-group_replication_single_primary_mode=off //關閉單master模式 loose-group_replication_enforce_update_everywhere_checks=ON //開啟多主一致性檢查
然後全部服務器停止組復制（GROUP_REPLICATION）集群，並設置參數
mysql> stop GROUP_REPLICATION; Query OK, 0 rows affected (9.51 sec) mysql> set global group_replication_single_primary_mode=off; //關閉單主模式 Query OK, 0 rows affected (0.00 sec) mysql> set global group_replication_enforce_update_everywhere_checks=ON; //開啟多主一致性檢查 Query OK, 0 rows affected (0.00 sec)
選擇其中一臺引導組復制（GROUP_REPLICATION）集群
mysql> SET GLOBAL group_replication_bootstrap_group=ON; Query OK, 0 rows affected (0.00 sec) mysql> START GROUP_REPLICATION; Query OK, 0 rows affected (2.13 sec) mysql> SET GLOBAL group_replication_bootstrap_group=OFF; Query OK, 0 rows affected (0.01 sec)
剩下的開啟組復制（GROUP_REPLICATION）即可
mysql> start group_replication; Query OK, 0 rows affected, 1 warning (6.05 sec)
最後查看非引導組復制的服務器
mysql> select * from performance_schema.replication_group_members; +---------------------------+--------------------------------------+-------------+-------------+--------------+ | CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | +---------------------------+--------------------------------------+-------------+-------------+--------------+ | group_replication_applier | 74df3399-91b8-11e9-be5f-000c299fdf40 | youxi3 | 3306 | ONLINE | | group_replication_applier | 8fbf8b41-84fe-11e9-897e-000c29f27e52 | youxi2 | 3306 | ONLINE | | group_replication_applier | c9e3662b-9020-11e9-94aa-000c29721e89 | youxi1 | 3306 | ONLINE | +---------------------------+--------------------------------------+-------------+-------------+--------------+ 3 rows in set (0.00 sec) mysql> show variables like '%read_only%'; +-----------------------+-------+ | Variable_name | Value | +-----------------------+-------+ | innodb_read_only | OFF | | read_only | OFF | | super_read_only | OFF | | transaction_read_only | OFF | | tx_read_only | OFF | +-----------------------+-------+ 5 rows in set (0.01 sec)
(3).如果宕機瞭
停掉youxi1的mysqld模擬宕機
[root@youxi1 ~]# systemctl stop mysqld
這時候查看youxi2和youxi3誰是新的master
[root@youxi2 ~]# mysql -uroot -p123456 mysql> show variables like '%read_only%'; //這是youxi2的 +-----------------------+-------+ | Variable_name | Value | +-----------------------+-------+ | innodb_read_only | OFF | | read_only | ON | | super_read_only | ON | | transaction_read_only | OFF | | tx_read_only | OFF | +-----------------------+-------+ 5 rows in set (0.00 sec) [root@youxi3 ~]# mysql -uroot -p123456 mysql> show variables like '%read_only%'; //這是youxi3的，可以看出youxi3成為瞭新的master +-----------------------+-------+ | Variable_name | Value | +-----------------------+-------+ | innodb_read_only | OFF | | read_only | OFF | | super_read_only | OFF | | transaction_read_only | OFF | | tx_read_only | OFF | +-----------------------+-------+ 5 rows in set (0.00 sec)
在youxi3上寫入數據，這是因為生產環境數據庫是一直在使用的狀態，不可能等你修復後再用
[root@youxi3 ~]# mysql -uroot -p123456 mysql> insert into test_db.user_tb values(2,'lisi'); Query OK, 1 row affected (0.03 sec) mysql> select * from test_db.user_tb; +----+----------+ | id | name | +----+----------+ | 1 | zhangsan | | 2 | lisi | +----+----------+ 2 rows in set (0.00 sec)
將修好的youxi1添加回復制組
[root@youxi1 ~]# systemctl start mysqld [root@youxi1 ~]# mysql -uroot -p123456 mysql> select * from performance_schema.replication_group_members; +---------------------------+-----------+-------------+-------------+--------------+ | CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | +---------------------------+-----------+-------------+-------------+--------------+ | group_replication_applier | | | NULL | OFFLINE | +---------------------------+-----------+-------------+-------------+--------------+ 1 row in set (0.00 sec) mysql> change master to master_user='repl',master_password='12345678' for channel 'group_replication_recovery'; //這一步是為瞭以防萬一， Query OK, 0 rows affected, 2 warnings (0.01 sec) mysql> set global group_replication_allow_local_disjoint_gtids_join=ON; //將這臺服務器重新添加進復制組 Query OK, 0 rows affected (0.00 sec) mysql> start group_replication; Query OK, 0 rows affected (3.36 sec) mysql> select * from performance_schema.replication_group_members; //查看是否加入復制組 +---------------------------+--------------------------------------+-------------+-------------+--------------+ | CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | +---------------------------+--------------------------------------+-------------+-------------+--------------+ | group_replication_applier | 07c6f159-964f-11e9-b2c7-000c2934a723 | youxi3 | 3306 | ONLINE | | group_replication_applier | 8247f048-962f-11e9-a210-000c2975fa5d | youxi2 | 3306 | ONLINE | | group_replication_applier | 8b703193-962a-11e9-b582-000c29e6d627 | youxi1 | 3306 | ONLINE | +---------------------------+--------------------------------------+-------------+-------------+--------------+ 3 rows in set (0.00 sec) mysql> select * from test_db.user_tb; //查看是否同步數據，沒有同步請耐心等待，時間可能會長點 +----+----------+ | id | name | +----+----------+ | 1 | zhangsan | | 2 | lisi | +----+----------+ 2 rows in set (0.00 sec)
到此這篇關於MGR集群搭建的文章就介紹到這瞭,更多相關MGR集群搭建內容請搜索WalkonNet以前的文章或繼續瀏覽下面的相關文章希望大傢以後多多支持WalkonNet！
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