MySQL集羣搭建(2)-主主從模式

時間  2019-11-10
標籤 mysql 集羣 搭建 主從 模式 欄目 MySQL 简体版
原文   原文鏈接

讓咱們繼續 MySQL 集羣搭建之旅，大部分 MySQL 的集羣都是採用主主從的經典模式，這也是部署高可用集羣的基礎。從上文咱們已經知道若是搭建 MySQL 的主備模式，若是沒看過的能夠了解一下。mysql

1 環境準備

上次咱們搭建了主備架構，以下所示sql

圖片描述

此次咱們的搭建目標是數據庫

圖片描述

具體配置信息segmentfault

IP 系統 端口 MySQL版本 節點 讀寫 說明
192.168.41.83 Centos6.8 3306 5.7.20 Master 讀寫 主節點
192.168.41.72 Centos6.8 3306 5.7.20 Standby 只讀,可切換爲讀寫 備節點，容許升級爲主節點
192.168.41.83 Centos6.8 3307 5.7.20 Slave 只讀 從節點

環境我已經準備好了, 以下圖所示，若是不知道如何安裝 MySQL 和搭建主備能夠參考之前的文章服務器

圖片描述

參考配置架構

Mastersocket

[client]
port = 3306
default-character-set=utf8mb4
socket = /data/mysql_db/mysql_seg_3306/mysql.sock

[mysqld]
datadir = /data/mysql_db/mysql_seg_3306
basedir = /usr/local/mysql57
tmpdir = /tmp
socket = /data/mysql_db/mysql_seg_3306/mysql.sock
pid-file = /data/mysql_db/mysql_seg_3306/mysql.pid
skip-external-locking = 1
skip-name-resolve = 1
port = 3306
server_id = 833306

default-storage-engine = InnoDB
character-set-server = utf8mb4
default_password_lifetime=0

auto_increment_offset = 1
auto_increment_increment = 2

#### log ####
log_timestamps=system
log_bin = /data/mysql_log/mysql_seg_3306/mysql-bin
log_bin_index = /data/mysql_log/mysql_seg_3306/mysql-bin.index
binlog_format = row
relay_log_recovery=ON
relay_log=/data/mysql_log/mysql_seg_3306/mysql-relay-bin
relay_log_index=/data/mysql_log/mysql_seg_3306/mysql-relay-bin.index
log_error = /data/mysql_log/mysql_seg_3306/mysql-error.log

#### replication ####
log_slave_updates = 1
replicate_wild_ignore_table = information_schema.%,performance_schema.%,sys.%

#### semi sync replication settings #####
plugin_dir=/usr/local/mysql57/lib/plugin
plugin_load = "rpl_semi_sync_master=semisync_master.so;rpl_semi_sync_slave=semisync_slave.so"
loose_rpl_semi_sync_master_enabled = 1
loose_rpl_semi_sync_slave_enabled = 1
loose_rpl_semi_sync_master_timeout = 5000

Standby測試

[client]
port = 3306
default-character-set=utf8mb4
socket = /data/mysql_db/mysql_seg_3306/mysql.sock

[mysqld]
datadir = /data/mysql_db/mysql_seg_3306
basedir = /usr/local/mysql57
tmpdir = /tmp
socket = /data/mysql_db/mysql_seg_3306/mysql.sock
pid-file = /data/mysql_db/mysql_seg_3306/mysql.pid
skip-external-locking = 1
skip-name-resolve = 1
port = 3306
server_id = 723306

default-storage-engine = InnoDB
character-set-server = utf8mb4
default_password_lifetime=0

auto_increment_offset = 2
auto_increment_increment = 2

#### log ####
log_timestamps=system
log_bin = /data/mysql_log/mysql_seg_3306/mysql-bin
log_bin_index = /data/mysql_log/mysql_seg_3306/mysql-bin.index
binlog_format = row
relay_log_recovery=ON
relay_log=/data/mysql_log/mysql_seg_3306/mysql-relay-bin
relay_log_index=/data/mysql_log/mysql_seg_3306/mysql-relay-bin.index
log_error = /data/mysql_log/mysql_seg_3306/mysql-error.log

#### replication ####
log_slave_updates = 1
replicate_wild_ignore_table = information_schema.%,performance_schema.%,sys.%

#### semi sync replication settings #####
plugin_dir=/usr/local/mysql57/lib/plugin
plugin_load = "rpl_semi_sync_master=semisync_master.so;rpl_semi_sync_slave=semisync_slave.so"
loose_rpl_semi_sync_master_enabled = 1
loose_rpl_semi_sync_slave_enabled = 1
loose_rpl_semi_sync_master_timeout = 5000

Slavespa

[client]
port = 3307
default-character-set=utf8mb4
socket = /data/mysql_db/mysql_seg_3307/mysql.sock

[mysqld]
datadir = /data/mysql_db/mysql_seg_3307
basedir = /usr/local/mysql57
tmpdir = /tmp
socket = /data/mysql_db/mysql_seg_3307/mysql.sock
pid-file = /data/mysql_db/mysql_seg_3307/mysql.pid
skip-external-locking = 1
skip-name-resolve = 1
port = 3307
server_id = 833307
read_only=1

default-storage-engine = InnoDB
character-set-server = utf8mb4
default_password_lifetime=0

#### log ####
log_timestamps=system
log_bin = /data/mysql_log/mysql_seg_3307/mysql-bin
log_bin_index = /data/mysql_log/mysql_seg_3307/mysql-bin.index
binlog_format = row
relay_log_recovery=ON
relay_log=/data/mysql_log/mysql_seg_3307/mysql-relay-bin
relay_log_index=/data/mysql_log/mysql_seg_3307/mysql-relay-bin.index
log_error = /data/mysql_log/mysql_seg_3307/mysql-error.log

#### replication ####
replicate_wild_ignore_table = information_schema.%,performance_schema.%,sys.%

#### semi sync replication settings #####
plugin_dir=/usr/local/mysql57/lib/plugin
plugin_load = "rpl_semi_sync_master=semisync_master.so;rpl_semi_sync_slave=semisync_slave.so"
loose_rpl_semi_sync_master_enabled = 1
loose_rpl_semi_sync_slave_enabled = 1
loose_rpl_semi_sync_master_timeout = 5000

配置解釋日誌

  • auto_increment_offset 自增字段起始值，設置爲 2 表示自增字段從 2 開始算
  • auto_increment_increment 自增字段步增數值，設置爲 2 表示每次遞增 2，根據主節點設置，自增字段的值多是這樣的: 1,3,5,7...
  • log_slave_updates 將複製事件寫入 binlog, 一臺服務器既作主庫又作從庫此選項必需要開啓, 這裏在 Master 和 Standby 開啓

說明一下，設置 auto_increment_offset, auto_increment_increment 是爲了防止兩個節點雙寫時出現主鍵衝突

2 搭建主主

如今環境已經準備好了，當前部署狀態爲，Standby 向 Master 同步，Slave 空跑, 如今開始搭建雙主架構

2.1 記錄 Standy 節點二進制位置

要實現 Master 向 Slave 同步，說簡單點就是反着搭建主備同步。咱們先去備節點記錄當前二進制日誌狀態

db72-3306>>show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000005 |      154 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

正常狀況下，主節點一直有數據寫入，而咱們又設置了 log_slave_updates，有同窗會疑惑，在咱們記錄當前二進制位置後，若是有數據同步過來，二進制位置變化了，而咱們從舊數據開始同步，會不會發生數據衝突。其實不會，雙主模式下，數據庫會幫咱們處理這種狀況，如今咱們模擬這種狀況，在主節點插入一些數據

db83-3306>>insert into test1 values (0, 'echoQMC', 24);
Query OK, 1 row affected (0.01 sec)

db83-3306>>select * from test1;
+----+---------+-----+
| id | name    | age |
+----+---------+-----+
|  1 | a       |  16 |
|  2 | b       |  17 |
|  3 | c       |  18 |
|  4 | d       |  19 |
|  5 | chengqm |  24 |
|  7 | echoQMC |  24 |
+----+---------+-----+
6 rows in set (0.00 sec)

插入數據後，咱們再看 Standby 二進制位置

db72-3306>>show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000005 |      424 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

2.2 在主節點開啓同步

根據咱們第一次獲取到的二進制日誌位置，在 Master 節點執行如下命令即可以開啓同步

-- 重置複製
-- reset slave;

-- 同步配置
CHANGE MASTER TO
MASTER_HOST='192.168.41.72',
MASTER_PORT=3306,
MASTER_USER='repl',
MASTER_PASSWORD='repl',
MASTER_LOG_FILE='mysql-bin.000005',
MASTER_LOG_POS=154;

-- 開啓同步
start slave

具體執行過程以下

db83-3306>>CHANGE MASTER TO
    -> MASTER_HOST='192.168.41.72',
    -> MASTER_PORT=3306,
    -> MASTER_USER='repl',
    -> MASTER_PASSWORD='repl',
    -> MASTER_LOG_FILE='mysql-bin.000005',
    -> MASTER_LOG_POS=154;
Query OK, 0 rows affected, 2 warnings (0.00 sec)

db83-3306>>start slave;
Query OK, 0 rows affected (0.00 sec)

查看同步狀態

db83-3306>>show slave status \G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.41.72
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000005
          Read_Master_Log_Pos: 424
               Relay_Log_File: mysql-relay-bin.000002
                Relay_Log_Pos: 320
        Relay_Master_Log_File: mysql-bin.000005
             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: information_schema.%,performance_schema.%,sys.%
                   Last_Errno: 0
                   Last_Error: 
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 424
              Relay_Log_Space: 527
              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: 723306
                  Master_UUID: f9610603-e99f-11e8-b980-90b11c1a653a
             Master_Info_File: /data/mysql_db/mysql_seg_3306/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: 
            Executed_Gtid_Set: 
                Auto_Position: 0
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
1 row in set (0.00 sec)

ERROR: 
No query specified

能夠發現同步正常，沒有數據衝突的狀況，如今測試一下在 Standby 寫數據會不會同步到 Master

db72-3306>>insert into test1 values (0, 'Keeming', 24);
Query OK, 1 row affected (0.04 sec)

在 Master 節點查看數據

db83-3306>>select * from test1;
+----+---------+-----+
| id | name    | age |
+----+---------+-----+
|  1 | a       |  16 |
|  2 | b       |  17 |
|  3 | c       |  18 |
|  4 | d       |  19 |
|  5 | chengqm |  24 |
|  7 | echoQMC |  24 |
|  8 | Keeming |  24 |
+----+---------+-----+
7 rows in set (0.00 sec)

數據被同步過來，雙主架構已經搭建成功，當前架構以下

圖片描述

仔細觀察主鍵的遞增狀況，咱們發如今 Master 節點插入 echoQMC 這條數據，主鍵從 5 跳到 7，在 Standby 節點插入 Keeming 這條數據，主鍵從 7 跳到 8，說明主鍵遞增是不同的，在 Master 插入數據只會有單數主鍵， 在 Standby 插入數據只會有雙數主鍵，這樣即便同時在兩個節點寫數據，也不會有衝突

2.3 從庫開啓同步

主主架構已經搭建成功，如今咱們再增長一個 Slave 節點，向 Master 同步，這個過程就是簡單的主備搭建，具體過程就不贅述了。

在使用主主從架構下，爲了數據一致性，咱們通常只容許一個節點有寫操做，其餘節點都設爲只讀，因此在 Slave 配置文件裏面加上了 read_only, Standby 節點手動設置只讀(方便切換)

全部操做完成後，架構以下

圖片描述

到此，主主備架構搭建完成

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