前言
在企业中，数据库高可用一直是企业的重中之重，中小企业很多都是使用mysql主从方案，一主多从，读写分离等，但是单主存在单点故障，从库切换成主库需要作改动。因此，如果是双主或者多主，就会增加mysql入口，增加高可用。不过多主需要考虑自增长ID问题，这个需要特别设置配置文件，比如双主，可以使用奇偶，总之，主之间设置自增长ID相互不冲突就能完美解决自增长ID冲突问题。
MySQL双主（主主）架构方案思路是
1.两台mysql都可读写，互为主备，默认只使用一台（masterA）负责数据的写入，另一台（masterB）备用；
2.masterA是masterB的主库，masterB又是masterA的主库，它们互为主从；
3.两台主库之间做高可用,可以采用keepalived等方案（使用VIP对外提供服务）；
4.所有提供服务的从服务器与masterB进行主从同步（双主多从）;
5.建议采用高可用策略的时候，masterA或masterB均不因宕机恢复后而抢占VIP（非抢占模式）；
演示：MySQL双主架构实现
环境：
主1服务器端IP: 10.220.5.137
主2服务器端IP: 10.220.5.138
1.首先需要修改主服务器端配置文件
1 #my.cnf 2 [client] 3 port = 3306 4 socket = /tmp/mysql3306.sock 5 6 [mysql] 7 #prompt="\u@\h:\p [\d]>" 8 #pager="less -i -n -S" 9 #tee=/opt/mysql/query.log 10 no-auto-rehash 11 12 [mysqld] 13 #misc 14 user = mysql 15 basedir = /usr/local/mysql 16 datadir = /data/mysql/mysql3306/data 17 port = 3306 18 socket = /tmp/mysql3306.sock 19 event_scheduler = 0 20 #skip-grant 21 22 tmpdir = /data/mysql/mysql3306/tmp 23 #timeout 24 interactive_timeout = 300 25 wait_timeout = 300 26 #auto_increment_offset = 2 27 #auto_increment_increment = 2 28 29 #character set 30 character-set-server = utf8 32 open_files_limit = 65535 33 max_connections = 100 34 max_connect_errors = 100000 35 lower_case_table_names =1 36 auto_increment_offset=1 <<从1开始增长 37 auto_increment_increment=2 <<每次增长为2，即为奇数 38 39 #symi replication 40 41 #rpl_semi_sync_master_enabled=1 42 #rpl_semi_sync_master_timeout=1000 # 1 second 43 #rpl_semi_sync_slave_enabled=1 44 45 #logs 46 log-output=file 47 slow_query_log = 1 48 slow_query_log_file = slow.log 49 log-error = error.log 50 log_warnings = 2 51 pid-file = mysql.pid 52 long_query_time = 1 53 #log-slow-admin-statements = 1 54 #log-queries-not-using-indexes = 1 55 log-slow-slave-statements = 1 56 57 #binlog 58 #binlog_format = STATEMENT 59 binlog_format = row 60 server-id = 1003306 61 log-bin = /data/mysql/mysql3306/logs/mysql-bin 62 binlog_cache_size = 4M 63 max_binlog_size = 256M 64 max_binlog_cache_size = 1M 65 sync_binlog = 0 66 expire_logs_days = 10 67 #procedure 68 log_bin_trust_function_creators=1 69 70 # 71 gtid-mode = on 72 enforce-gtid-consistency=1 73 74 75 #relay log 76 skip_slave_start = 1 77 max_relay_log_size = 128M 78 relay_log_purge = 1 79 relay_log_recovery = 1 80 relay-log=relay-bin 81 relay-log-index=relay-bin.index 82 log_slave_updates 83 #slave-skip-errors=1032,1053,1062 84 #skip-grant-tables 85 86 #buffers & cache 87 table_open_cache = 2048 88 table_definition_cache = 2048 89 tabl90 max_heap_table_size = 96M 91 sort_buffer_size = 128K 92 join_buffer_size = 128K 93 thread_cache_size = 200 94 query_cache_size = 0 95 query_cache_type = 0 96 query_cache_limit = 256K 97 query_cache_min_res_unit = 512 98 thread_stack = 192K 99 tmp_table_size = 96M 100 key_buffer_size = 8M 101 read_buffer_size = 2M 102 read_rnd_buffer_size = 16M 103 bulk_insert_buffer_size = 32M 104 105 #myisam 106 myisam_sort_buffer_size = 128M 107 myisam_max_sort_file_size = 10G 108 myisam_repair_threads = 1 109 110 #innodb 111 innodb_buffer_pool_size = 100M 112 innodb_buffer_pool_instances = 1 113 innodb_data_file_path = ibdata1:100M:autoextend 114 innodb_flush_log_at_trx_commit = 2 115 innodb_log_buffer_size = 8M 116 innodb_log_file_size = 100M 117 innodb_log_files_in_group = 3 118 innodb_max_dirty_pages_pct = 50 119 innodb_file_per_table = 1e_open_cache = 2048 120 innodb_rollback_on_timeout 121 innodb_status_file = 1 122 innodb_io_capacity = 100 123 transaction_isolation = READ-COMMITTED 124 innodb_flush_method = O_DIRECT
2.启动mysql并创建复制用的用户
[root@ken ~]# mysqld & <<启动mysql [4] 2896 [root@ken ~]# mysql -uroot -p <<登录mysql Enter password: Welcome to the MySQL monitor. Commands end with ; or g. Your MySQL connection id is 7 Server version: 5.7.23-log MySQL Community Server (GPL) Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or 'h' for help. Type 'c' to clear the current input statement. mysql> grant replication slave on *.* to ken@'%' identified by 'xx'; <<创建复制用的用户
3.检查主2的二进制日志文件位置，在主2服务器上面执行下面的命令获取到当前二进制日志记录位置
MySQL [ken]> show master statusG *************************** 1. row *************************** File: mysql-bin.000004 Position: 1558 Binlog_Do_DB: Binlog_Ignore_DB: Executed_Gtid_Set: 987ac782-d7b8-11e8-a462-000c292218ec:1-5, c01b1811-d7b3-11e8-8698-000c29492f7b:1-3 1 row in set (0.00 sec)
4.连接到主2服务器上面
change master to master_host='10.220.5.138',master_user='ken',master_password='xx',master_log_file='mysql-bin.000004',master_log_pos=1558;
5.启动slave
mysql> start slave;
6.检查连接状态
mysql> show slave statusG ERROR 2006 (HY000): MySQL server has gone away No connection. Trying to reconnect... Connection id: 8 Current database: *** NONE *** *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 10.220.5.138 Master_User: ken Master_Port: 3306 Connect_Retry: 60 Master_Log_File: mysql-bin.000004 Read_Master_Log_Pos: 1558 Relay_Log_File: relay-bin.000004 Relay_Log_Pos: 602 Relay_Master_Log_File: mysql-bin.000004 Slave_IO_Running: Yes <<IO线程启动成功 Slave_SQL_Running: Yes <<SQL线程启动成功 Replicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0 Last_Error: Skip_Counter: 0 Exec_Master_Log_Pos: 1558 Relay_Log_Space: 803 Until_Condition: None Until_Log_File: Until_Log_Pos: 0 Master_SSL_Allowed: No Master_SSL_CA_File: Master_SSL_CA_Path: Master_SSL_Cert: Master_SSL_Cipher: Master_SSL_Key: Seconds_Behind_Master: 0 Master_SSL_Verify_Server_Cert: No Last_IO_Errno: 0 Last_IO_Error: Last_SQL_Errno: 0 Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 1003307 Master_UUID: c01b1811-d7b3-11e8-8698-000c29492f7b Master_Info_File: /data/mysql/mysql3306/data/master.info SQL_Delay: 0 SQL_Remaining_Delay: NULL Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates Master_Retry_Count: 86400 Master_Bind: Last_IO_Error_Timestamp: Last_SQL_Error_Timestamp: Master_SSL_Crl: Master_SSL_Crlpath: Retrieved_Gtid_Set: c01b1811-d7b3-11e8-8698-000c29492f7b:3 Executed_Gtid_Set: 987ac782-d7b8-11e8-a462-000c292218ec:1-5, c01b1811-d7b3-11e8-8698-000c29492f7b:3 Auto_Position: 0 Replicate_Rewrite_DB: Channel_Name: Master_TLS_Version: 1 row in set (0.01 sec)
主1节点配置完毕，并且启动成功，下面来配置主2服务器。
1.修改主2配置文件
1 #my.cnf 2 [client] 3 port = 3306 4 socket = /tmp/mysql3306.sock 5 6 [mysql] 7 #prompt="\u@\h:\p [\d]>" 8 #pager="less -i -n -S" 9 #tee=/opt/mysql/query.log 10 no-auto-rehash 11 12 [mysqld] 13 #misc 14 user = mysql 15 basedir = /usr/local/mysql 16 datadir = /data/mysql/mysql3306/data 17 port = 3306 18 socket = /tmp/mysql3306.sock 19 event_scheduler = 0 20 #skip-grant 21 22 tmpdir = /data/mysql/mysql3306/tmp 23 #timeout 24 interactive_timeout = 300 25 wait_timeout = 300 26 #auto_increment_offset = 2 27 #auto_increment_increment = 2 28 29 #character set 30 character-set-server = utf8 32 open_files_limit = 65535 33 max_connections = 100 34 max_connect_errors = 100000 35 lower_case_table_names =1 36 auto_increment_offset=2 <<从2开始增长 37 auto_increment_increment=2 <<每次增长为2，即为偶数 38 39 #symi replication 40 41 #rpl_semi_sync_master_enabled=1 42 #rpl_semi_sync_master_timeout=1000 # 1 second 43 #rpl_semi_sync_slave_enabled=1 44 45 #logs 46 log-output=file 47 slow_query_log = 1 48 slow_query_log_file = slow.log 49 log-error = error.log 50 log_warnings = 2 51 pid-file = mysql.pid 52 long_query_time = 1 53 #log-slow-admin-statements = 1 54 #log-queries-not-using-indexes = 1 55 log-slow-slave-statements = 1 56 57 #binlog 58 #binlog_format = STATEMENT 59 binlog_format = row 60 server-id = 1003307 <<两个服务器的server_id必须不一致 61 log-bin = /data/mysql/mysql3306/logs/mysql-bin 62 binlog_cache_size = 4M 63 max_binlog_size = 256M 64 max_binlog_cache_size = 1M 65 sync_binlog = 0 66 expire_logs_days = 10 67 #procedure 68 log_bin_trust_function_creators=1 69 70 # 71 gtid-mode = on 72 enforce-gtid-consistency=1 73 74 75 #relay log 76 skip_slave_start = 1 77 max_relay_log_size = 128M 78 relay_log_purge = 1 79 relay_log_recovery = 1 80 relay-log=relay-bin 81 relay-log-index=relay-bin.index 82 log_slave_updates 83 #slave-skip-errors=1032,1053,1062 84 #skip-grant-tables 85 86 #buffers & cache 87 table_open_cache = 2048 88 table_definition_cache = 2048 89 tabl90 max_heap_table_size = 96M 91 sort_buffer_size = 128K 92 join_buffer_size = 128K 93 thread_cache_size = 200 94 query_cache_size = 0 95 query_cache_type = 0 96 query_cache_limit = 256K 97 query_cache_min_res_unit = 512 98 thread_stack = 192K 99 tmp_table_size = 96M 100 key_buffer_size = 8M 101 read_buffer_size = 2M 102 read_rnd_buffer_size = 16M 103 bulk_insert_buffer_size = 32M 104 105 #myisam 106 myisam_sort_buffer_size = 128M 107 myisam_max_sort_file_size = 10G 108 myisam_repair_threads = 1 109 110 #innodb 111 innodb_buffer_pool_size = 100M 112 innodb_buffer_pool_instances = 1 113 innodb_data_file_path = ibdata1:100M:autoextend 114 innodb_flush_log_at_trx_commit = 2 115 innodb_log_buffer_size = 8M 116 innodb_log_file_size = 100M 117 innodb_log_files_in_group = 3 118 innodb_max_dirty_pages_pct = 50 119 innodb_file_per_table = 1e_open_cache = 2048 120 innodb_rollback_on_timeout 121 innodb_status_file = 1 122 innodb_io_capacity = 100 123 transaction_isolation = READ-COMMITTED 124 innodb_flush_method = O_DIRECT
2.启动mysql并创建复制用的用户
[root@ken ~]# mysqld & <<启动mysql
[4] 2896
[root@ken ~]# mysql -uroot -p <<登录mysql
Enter password:
Welcome to the MySQL monitor. Commands end with ; or g.
Your MySQL connection id is 7
Server version: 5.7.23-log MySQL Community Server (GPL)
Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
mysql> grant replication slave on *.* to ken@'%' identified by 'xx'; <<创建复制用的用户
3.检查主1的二进制日志文件位置，在主1服务器上面执行下面的命令获取到当前二进制日志记录位置
mysql> show master statusG
*************************** 1. row ***************************
File: mysql-bin.000009
Position: 1526
Binlog_Do_DB:
Binlog_Ignore_DB:
Executed_Gtid_Set: 987ac782-d7b8-11e8-a462-000c292218ec:1-5,
c01b1811-d7b3-11e8-8698-000c29492f7b:3
1 row in set (0.01 sec)
4.连接到主2服务器上面
change master to master_host='10.220.5.137',master_user='ken',master_password='xx',master_log_file='mysql-bin.000009',master_log_pos=1526;
5.启动slave
mysql> start slave;
6.检查连接状态
mysql> show slave statusG
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id: 8
Current database: *** NONE ***
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 10.220.5.137
Master_User: ken
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000009
Read_Master_Log_Pos: 1558
Relay_Log_File: relay-bin.000009
Relay_Log_Pos: 602
Relay_Master_Log_File: mysql-bin.000009
Slave_IO_Running: Yes <<IO线程启动成功
Slave_SQL_Running: Yes <<SQL线程启动成功
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 1558
Relay_Log_Space: 803
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 1003307
Master_UUID: c01b1811-d7b3-11e8-8698-000c29492f7b
Master_Info_File: /data/mysql/mysql3306/data/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set: c01b1811-d7b3-11e8-8698-000c29492f7b:3
Executed_Gtid_Set: 987ac782-d7b8-11e8-a462-000c292218ec:1-5,
c01b1811-d7b3-11e8-8698-000c29492f7b:3
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
1 row in set (0.01 sec)
现在两个主服务器都已经搭建完，现在来进行测试
1.首先在主1服务器上面建表建库并插入数据
mysql> create database ken; <<创建数据库 mysql> use ken; <<切换数据库 mysql> create table tb2(id int primary key auto_increment,name char(30)); <<创建表 mysql> insert into tb2 (name) values('kk'),('kkl'),('dad'); <<插入数据 mysql> select * from tb2; <<检查数据，为奇数排列 +----+------+ | id | name | +----+------+ | 1 | kk | | 3 | kkl | | 5 | dad |
2.登录主2服务器并检查是否已经有主1上面建的表库
MySQL [ken]> select * from tb2; <<同步成功 +----+------+ | id | name | +----+------+ | 1 | kk | | 3 | kkl | | 5 | dad |
3.在主2服务器上面插入数据，检查数据是否会冲突以及同步到主1
MySQL [ken]> insert into tb2 (name) values('lll'),('lll'),('lll'); MySQL [ken]> select * from tb2; +----+------+ | id | name | +----+------+ | 1 | kk | | 3 | kkl | | 5 | dad | | 6 | lll | <<偶数排序 | 8 | lll | | 10 | lll | +----+------+ 6 rows in set (0.00 sec)
4.检查主1服务器是否已经同步过来
mysql> select * from tb2; +----+------+ | id | name | +----+------+ | 1 | kk | | 3 | kkl | | 5 | dad | | 6 | lll | | 8 | lll | | 10 | lll | +----+------+ 6 rows in set (0.00 sec)
同步成功！这样就实现了mysql双主的架构.