mysql主从复制

原理：

    主节点生成了二进制日志文件之后，从节点的i/o thread发送读请求，主节点经由dump发送给从节点的中继日志，最后由SQL thread读取中继日志中的内容replay完成复制。

QQ截图20170917185021.png

准备环境：

    主节点：192.168.52.138
    从节点：192.168.52.139

禁用selinux策略，清空防火墙规则

    iptables -F
    setenforce 0

更改配制文件：

    主节点：
    Vim /etc/my.cnf.d/server.cnf
    [mysqld]
    log_bin=master-log
    server_id=1
    skip_name_resolve=on
    从节点：
    [mysqld]
    server-id=7
    relay-log=relay-log
    skip_name_resolve=on

配置完成后启动服务：

    systemvtl start mariadb
    ss -ntl | grep '3306'
    确保3306端口打开

主从配置：

    在主节点上授权一个用户
    MariaDB [(none)]> grant replication client,replication slave on *.* to 'kongbinquan'@'192.168.52.139' identified by 'kbq';
    Query OK, 0 rows affected (0.00 sec）
    并找出当前所在节点：
    MariaDB [(none)]> SHOW MASTER STATUS;
    +-------------------+----------+--------------+------------------+
    | File              | Position | Binlog_Do_DB | Binlog_Ignore_DB |
    +-------------------+----------+--------------+------------------+
    | master-log.000006 |      423 |              |                  |
    +-------------------+----------+--------------+------------------+
    1 row in set (0.00 sec)
    接着在从节点上配置：
    
    MariaDB [(none)]> change master to    master_host='192.168.52.138',master_user='kongbinquan',master_password='kbq',master_log_file='master-log.000006', master_log_pos=423;
    Query OK, 0 rows affected (0.03 sec)

从节点状态：

    MariaDB [(none)]> start slave  ;
    Query OK, 0 rows affected (0.02 sec)
    MariaDB [(none)]>  SHOW SLAVE STATUS\G;
    *************************** 1. row ***************************
           Slave_IO_State: Waiting for master to send event
              Master_Host: 192.168.52.138
              Master_User: kongbinquan
              Master_Port: 3306
            Connect_Retry: 60
          Master_Log_File: master-log.000006
      Read_Master_Log_Pos: 423
           Relay_Log_File: relay-log.000002
            Relay_Log_Pos: 530
    Relay_Master_Log_File: master-log.000006
         Slave_IO_Running: Yes
        Slave_SQL_Running: Yes
          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: 423
          Relay_Log_Space: 818
          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: 1
  1 row in set (0.00 sec)