MGR部署
场景描述:
使用三台服务器搭建一个简单MGR集群,使用MySQL 5.7.24版本,服务器列表为:
192.168.1.147 192.168.1.148 192.168.1.149
1、使用普通配置文件启动MySQL服务,安装MGR插件(所有节点执行)
INSTALL PLUGIN group_replication SONAME 'group_replication.so';
2、调整MySQL各节点的配置文件并重启MySQL服务(所有节点执行)
## 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"
未安装MGR插件前在配置文件加入MGR配置会报错。
MGR配置说明:上面黄色部分参数在很多配置文件中都没提到,但很可能会导致部署失败,尤其是loose-group_replication_ip_whitelist参数。
3、配置MGR通信账号,并清理MASTER(所有节点执行)
CREATE USER repl@'%' IDENTIFIED BY 'repl'; GRANT REPLICATION SLAVE ON *.* TO repl@'%'; RESET MASTER;
4、创建MGR依赖的复制环境(所有节点执行)
CHANGE MASTER TO MASTER_USER='repl', MASTER_PASSWORD='repl' FOR CHANNEL 'group_replication_recovery';
5、在主节点上启动MGR(在节点192.168.1.147上执行)
SET GLOBAL group_replication_bootstrap_group=ON; START group_replication; SET GLOBAL group_replication_bootstrap_group=off;
6、在辅助节点上启动MGR(在节点192.168.1.148和在节点192.168.1.149上执行)
START group_replication;
7、搭建完成后,可以使用下面语句查看状态:
## 查看各节点状态 SELECT * FROM performance_schema.replication_group_members; ## 查看当前MGR模式(单主还是多主) SELECT @@group_replication_single_primary_mode;
8、判断节点状态
## 查看当前节点状态 SELECT member_state FROM performance_schema.replication_group_members WHERE member_id=@@server_uuid; ## 通过节点是否可写来判断群集是否为主节点 SELECT * FROM performance_schema.global_variables WHERE variable_name IN ('read_only', 'super_read_only');
MGR成员的五种状态:
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节点
目前MySQL不支持自动扩展新节点并将全量数据同步到新节点,因此需要:
1、备份任一节点数据(MySQLDump或Xtrabackup)至新节点并还原
2、在新节点上设置与备份数据对应的Executed_Gtid_Set
3、在新节点上执行下面命令直接启动MGR复制即可。
CHANGE MASTER TO MASTER_USER='repl', MASTER_PASSWORD='repl' FOR CHANNEL 'group_replication_recovery'; START GROUP_REPLICATION;