MySQL5.7安裝+基於GTID主從複製+並行複製+增強半同步複製+讀寫分離+M-S-S架構(聯級複製)
實驗環境:
Centos7.2
角色
主機IP
server_id
資料狀態
Proxysql
192.168.148.62
null
無
Master
192.168.148.62
1
剛安裝的全新MySQL例項
Slave1
192.168.148.61
2
剛安裝的全新MySQL例項
Slave2
192.168.148.64
3
剛安裝的全新MySQL例項
一、安裝最新版本Mysql5.7
-
下載並安裝MySQL官方的 Yum Repository,並啟動mysql
[[email protected] ~]# yum -y install mysql57-community-release-el7-10.noarch.rpm
[[email protected] ~]# yum -y install mysql-community-server
[[email protected] ~]# systemctl start mysqld.service
[[email protected] ~]# systemctl status mysqld.service
-
檢視yum安裝後的初始root密碼
[[email protected] ~]# grep "password" /var/log/mysqld.log
2018-07-09T06:57:12.533269Z 1 [Note] A temporary password is generated for [email protected]: H9VtyDlad!T;
-
如下命令首次進入資料庫並修改密碼:
[[email protected] ~]# mysql -uroot -pH9VtyDlad!T
mysql> ALTER USER 'root'@'%' IDENTIFIED BY '123456';
說明:MySQL預設必須修改密碼之後才能操作資料庫,並滿足密碼複雜度要求
%' 所有情況都能訪問
‘localhost’ 本機才能訪問
’111.222.33.44‘ 指定 ip 才能訪問
至此mysql已安裝完成。
二、基於GTID主從同步
-
gtid基本概念
傳統的基於binlog position複製的方式有個嚴重的缺點:如果slave連線master時指定的binlog檔案錯誤或者position錯誤,會造成遺漏或者重複,很多時候前後資料是有依賴性的,這樣就會出錯而導致資料不一致。
從MYSQL5.6開始,mysql開始支援GTID複製。GTID的全稱是global transaction id,表示的是全域性事務ID。GTID的分配方式為uuid:trans_id,其中:
- uuid是每個mysql伺服器都唯一的,記錄在$datadir/auto.cnf中。如果複製結構中,任意兩臺伺服器uuid重複的話(比如直接冷備份時,auto.conf中的內容是一致的),在啟動複製功能的時候會報錯。這時可以刪除auto.conf檔案再重啟mysqld。
基於gtid複製的好處
從上面可以看出,gtid複製的優點大致有:
保證同一個事務在某slave上絕對只執行一次,沒有執行過的gtid事務總是會被執行。
不用像傳統複製那樣保證binlog的座標準確,因為根本不需要binlog以及座標。
故障轉移到新的master的時候很方便,簡化了很多工。
很容易判斷master和slave的資料是否一致。只要master上提交的事務在slave上也提交了,那麼一定是一致的。
當然,MySQL提供了選項可以控制跳過某些gtid事務,防止slave第一次啟動複製時執行master上的所有事務而導致耗時過久。
雖然對於row-based和statement-based的格式都能進行gtid複製,但建議採用row-based格式。
-
master配置
[[email protected] ~]# vim /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
symbolic-links=0
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
server-id=1 ##伺服器標識
binlog_format=row
log-bin=mysql-bin ##開啟二進位制日誌
gtid_mode=ON ## 開啟gtid模式
enforce-gtid-consistency=true ## 強制gtid複製
-
儲存退出後重啟mysql。
[[email protected] ~]# systemctl restart mysqld
-
進入資料庫並檢視Master狀態
[[email protected] ~]# mysql -uroot -p
Enter password:
mysql>
mysql> show master status ; ##檢視master狀態
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000003 | 154 | | | |
+------------------+----------+--------------+------------------+-------------------+
-
授權slave使用者,並重新整理許可權
mysql> grant REPLICATION SLAVE ON *.* to [email protected]'192.168.148.%' identified by ' yourpasswd ' ;
Query OK, 0 rows affected, 1 warning (0.01 sec)
mysql>flush privileges;
-
再次檢視master狀態
mysql> show master status;
+------------------+----------+--------------+------------------+----------------------------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+----------------------------------------+
| mysql-bin.000003 | 442 | | | 4e552c02-8345-11e8-b571-000c294897b5:1 |
+------------------+----------+--------------+------------------+----------------------------------------+
1 row in set (0.00 sec)
-
slave1配置
[[email protected] ~]# vim /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
symbolic-links=0
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
server-id=2 ##伺服器標識
binlog_format=row
gtid_mode=ON ## 開啟gtid模式
enforce-gtid-consistency=true ## 強制gtid複製
-
儲存退出並重啟mysql
[[email protected] mysql]# systemctl restart mysqld
-
進入資料庫
[[email protected] ~]# mysql -uroot -p
mysql>change master to master_host='192.168.148.62', master_user='otter', master_password='yourpasswd', master_auto_position=1; mysql> start slave; ##開啟slave mysql> show slave status\G; ##檢視狀態
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.148.62
Master_User: otter
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000003
Read_Master_Log_Pos: 1373
Relay_Log_File: localhost-relay-bin.000004
Relay_Log_Pos: 360
Relay_Master_Log_File: mysql-bin.000003
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
三、測試:
-
master新建個數據庫test, slave會自動同步
mysql> create database test;
Query OK, 1 row affected (0.00 sec)
mysql> use test;
Database changed
mysql> create table usertable (
-> username varchar(10) not null,
-> password varchar(16) not null);
Query OK, 0 rows affected (0.01 sec)
mysql> insert into usertable values('mark','westos');
Query OK, 1 row affected (0.06 sec)
mysql> insert into usertable values('harry','redhat');
Query OK, 1 row affected (0.00 sec)
mysql> select * from usertable;
+----------+----------+
| username | password |
+----------+----------+
| mark | westos |
| harry | redhat |
+----------+----------+
2 rows in set (0.00 sec)
-
slave1自動同步
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| test |
| xuehui |
+--------------------+
6 rows in set (0.00 sec)
mysql> use test;
Database changed
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| usertable |
+----------------+
1 row in set (0.00 sec)
mysql> select * from usertable;
+----------+----------+
| username | password |
+----------+----------+
| mark | westos |
| harry | redhat |
+----------+----------+
2 rows in set (0.00 sec)
四、slave1並行複製
編輯slave1配置檔案
[[email protected] mysql]# vim /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
symbolic-links=0
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
server-id=2 ##伺服器標識
binlog_format=row
gtid_mode=ON ## 開啟gtid模式
enforce-gtid-consistency=true ## 強制gtid複製
slave-parallel-type=LOGICAL_CLOCK ##開啟邏輯時鐘的複製
slave-parallel-workers=4 ##最大執行緒16
master_info_repository=TABLE
relay_log_info_repository=TABLE
relay_log_recovery=ON
-
儲存退出並重啟mysql
[[email protected] mysql]# systemctl restart mysqld
-
主庫master配置binlog_group_commit
[[email protected] ~]# vim /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
symbolic-links=0
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
server-id=1 ##伺服器標識
binlog_format=row
log-bin=mysql-bin ##開啟二進位制日誌
gtid_mode=ON ## 開啟gtid模式
enforce-gtid-consistency=true ## 強制gtid複製
rpl_semi_sync_master_enabled = 1
plugin-load=rpl_semi_sync_master=semisync_master.so
rpl_semi_sync_master_timeout = 1000 # 1s
##不配置binlog_group_commit從庫無法做到基於事物的並行複製。
binlog_group_commit_sync_delay = 100
binlog_group_commit_sync_no_delay_count = 10
##為了資料安全再配置
sync_binlog=1
innodb_flush_log_at_trx_commit=1
-
儲存退出並重啟mysql
[[email protected] mysql]# systemctl restart mysqld
-
進入slave1資料庫,檢視優化項
mysql> use mysql;
Database changed
mysql> show tables;
|....................................|
| slave_worker_info |
-
檢視4個執行緒
mysql> select * from slave_worker_info;
+----+----------------+---------------+-----------------+----------------+---------------------------+--------------------------+----------------------------+---------------------------+------------------+-----------------------+------------------------------------------------------------------+--------------+
| Id | Relay_log_name | Relay_log_pos | Master_log_name | Master_log_pos | Checkpoint_relay_log_name | Checkpoint_relay_log_pos | Checkpoint_master_log_name | Checkpoint_master_log_pos | Checkpoint_seqno | Checkpoint_group_size | Checkpoint_group_bitmap | Channel_name |
+----+----------------+---------------+-----------------+----------------+---------------------------+--------------------------+----------------------------+---------------------------+------------------+-----------------------+------------------------------------------------------------------+--------------+
| 1 | | 0 | | 0 | | 0 | | 0 | 0 | 64 | | |
| 2 | | 0 | | 0 | | 0 | | 0 | 0 | 64 | | |
| 3 | | 0 | | 0 | | 0 | | 0 | 0 | 64 | | |
| 4 | | 0 | | 0 | | 0 | | 0 | 0 | 64 | | |
+----+----------------+---------------+-----------------+----------------+---------------------------+--------------------------+----------------------------+---------------------------+------------------+-----------------------+------------------------------------------------------------------+--------------+
4 rows in set (0.00 sec)
五、增強半同步
半同步複製
預設情況下,MySQL的複製是非同步的,master將新生成的binlog傳送給各slave後,無需等待slave的ack回覆(slave將接收到的binlog寫進relay log後才會回覆ack),直接就認為這次DDL/DML成功了。半同步複製(semi-synchronous replication)是指master在將新生成的binlog傳送給各slave時,只需等待一個(預設)slave返回的ack資訊就返回成功。
MySQL 5.7對半同步複製作了大改進,新增了一個master執行緒。在MySQL 5.7以前,master上的binlog dump執行緒負責兩件事:dump日誌給slave的io_thread;接收來自slave的ack訊息。它們是序列方式工作的。在MySQL 5.7中,新增了一個專門負責接受ack訊息的執行緒ack collector thread。這樣master上有兩個執行緒獨立工作,可以同時傳送binlog到slave和接收slave的ack。還新增了幾個變數,其中最重要的是 rpl_semi_sync_master_wait_point ,它使得MySQL半同步複製有兩種工作模型。解釋如下。
半同步複製的兩種型別
從MySQL 5.7.2開始,MySQL支援兩種型別的半同步複製。這兩種型別由變數 rpl_semi_sync_master_wait_point (MySQL 5.7.2之前沒有該變數)控制,它有兩種值:AFTER_SYNC和AFTER_COMMIT。在MySQL 5.7.2之後,預設值為AFTER_SYNC,在此版本之前,等價的型別為AFTER_COMMIT。這個變數控制的是master何時提交、何時接收ack以及何時回覆成功資訊給客戶端的時間點。
- AFTER_SYNC模式:master將新的事務寫進binlog(buffer),然後傳送給slave,再sync到自己的binlog file(disk)。之後才允許接收slave的ack回覆,接收到ack之後才會提交事務,並返回成功資訊給客戶端。
- AFTER_COMMIT模式:master將新的事務寫進binlog(buffer),然後傳送給slave,再sync到自己的binlog file(disk),然後直接提交事務。之後才允許接收slave的ack回覆,然後再返回成功資訊給客戶端。
畫圖理解就很清晰。(前提:已經設定了sync_binlog=1,否則binlog刷盤時間由作業系統決定)
再來分析下這兩種模式的優缺點。
- AFTER_SYNC:
-
- 對於所有客戶端來說,它們看到的資料是一樣的,因為它們看到的資料都是在接收到slave的ack後提交後的資料。
- 這種模式下,如果master突然故障,不會丟失資料,因為所有成功的事務都已經寫進slave的relay log中了,slave的資料是最新的。
- AFTER_COMMIT:
-
- 不同客戶端看到的資料可能是不一樣的。對於發起事務請求的那個客戶端,它只有在master提交事務且收到slave的ack後才能看到提交的資料。但對於那些非本次事務的請求客戶端,它們在master提交後就能看到提交後的資料,這時候master可能還沒收到slave的ack。
- 如果master收到ack回覆前,slave和master都故障了,那麼將丟失這個事務中的資料。
在MySQL 5.7.2之前,等價的模式是 AFTER_COMMIT ,在此版本之後,預設的模式為 AFTER_SYNC ,該模式能最大程度地保證資料安全性,且效能上並不比 AFTER_COMMIT 差。
-
master與Slave命令列載入模組
master載入
mysql> INSTALL PLUGIN rpl_semi_sync_master SONAME 'semisync_master.so';
Query OK, 0 rows affected (0.05 sec)
mysql> show plugins;
+----------------------------+----------+--------------------+----------------------+---------+
| Name | Status | Type | Library | License |
+----------------------------+----------+--------------------+----------------------+---------+
| binlog | ACTIVE | STORAGE ENGINE | NULL | GPL |
| mysql_native_password | ACTIVE | AUTHENTICATION | NULL | GPL |
|。。。。。。。。。。。。。。。。。。。。。。。。。。。。。|
| validate_password | ACTIVE | VALIDATE PASSWORD | validate_password.so | GPL |
| rpl_semi_sync_master | ACTIVE | REPLICATION | semisync_master.so | GPL |
+----------------------------+----------+--------------------+----------------------+---------+
46 rows in set (0.00 sec)
檢視載入模組資訊
mysql> show variables like '%rpl_semi%';
+-------------------------------------------+------------+
| Variable_name | Value |
+-------------------------------------------+------------+
| rpl_semi_sync_master_enabled | OFF |
| rpl_semi_sync_master_timeout | 10000 |
| rpl_semi_sync_master_trace_level | 32 |
| rpl_semi_sync_master_wait_for_slave_count | 1 |
| rpl_semi_sync_master_wait_no_slave | ON |
| rpl_semi_sync_master_wait_point | AFTER_SYNC |
+-------------------------------------------+------------+
6 rows in set (0.01 sec)
mysql> set global rpl_semi_sync_master_enabled=1; ##global全域性 啟動半同步
Query OK, 0 rows affected (0.00 sec)
mysql> show variables like '%rpl_semi%';
+-------------------------------------------+------------+
| Variable_name | Value |
+-------------------------------------------+------------+
| rpl_semi_sync_master_enabled | ON |
| rpl_semi_sync_master_timeout | 10000 |
| rpl_semi_sync_master_trace_level | 32 |
| rpl_semi_sync_master_wait_for_slave_count | 1 |
| rpl_semi_sync_master_wait_no_slave | ON |
| rpl_semi_sync_master_wait_point | AFTER_SYNC |
+-------------------------------------------+------------+
6 rows in set (0.01 sec)
修改半同步預設超時時間
mysql> set global rpl_semi_sync_master_timeout = 1000;
Query OK, 0 rows affected (0.00 sec)
mysql> show variables like '%rpl_semi%';
+-------------------------------------------+------------+
| Variable_name | Value |
+-------------------------------------------+------------+
| rpl_semi_sync_master_enabled | ON |
| rpl_semi_sync_master_timeout | 1000 |
| rpl_semi_sync_master_trace_level | 32 |
| rpl_semi_sync_master_wait_for_slave_count | 1 |
| rpl_semi_sync_master_wait_no_slave | ON |
| rpl_semi_sync_master_wait_point | AFTER_SYNC |
+-------------------------------------------+------------+
6 rows in set (0.01 sec)
########################## 以上的啟動方式是在命令列操作 ########################################
slave1載入模組
mysql> install plugin rpl_semi_sync_slave SONAME 'semisync_slave.so'; ##載入slave模組
mysql> set global rpl_semi_sync_slave_enabled=1; ##開啟slave模組
mysql> show variables like '%rpl_semi%'; ##檢視資訊
+---------------------------------+-------+
| Variable_name | Value |
+---------------------------------+-------+
| rpl_semi_sync_slave_enabled | ON |
| rpl_semi_sync_slave_trace_level | 32 |
+---------------------------------+-------+
2 rows in set (0.01 sec)
mysql> STOP SLAVE IO_THREAD; ##關閉slaveIO執行緒
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id: 8
Current database: *** NONE ***
Query OK, 0 rows affected (0.01 sec)
mysql> START SLAVE IO_THREAD; ##開啟slaveIO執行緒
Query OK, 0 rows affected (0.00 sec)
mysql> show status like 'Rpl_semi_sync_slave_status';
+----------------------------+-------+
| Variable_name | Value |
+----------------------------+-------+
| Rpl_semi_sync_slave_status | ON |
+----------------------------+-------+
1 row in set (0.00 sec)
########################## 以上的啟動方式是在命令列操作 ########################################
-
配置檔案中載入。
主Master:配置檔案里加載semisync_master.so
[[email protected] ~]# vim /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
symbolic-links=0
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
server-id=1 ##伺服器標識
binlog_format=row
log-bin=mysql-bin ##開啟二進位制日誌
gtid_mode=ON
enforce-gtid-consistency=true
plugin-load=rpl_semi_sync_master=semisync_master.so
rpl_semi_sync_master_enabled = 1
rpl_semi_sync_master_timeout = 1000 # 1s
儲存退出並重啟mysql
[[email protected] mysql]# systemctl restart mysqld
Slave1: 配置檔案里加載semisync_slave.so,並開啟bin-log日誌
[[email protected] mysql]# vim /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
symbolic-links=0
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
server-id=2 ##伺服器標識
binlog_format=row
gtid_mode=ON ## 開啟gtid模式
log-bin=mysql-bin-slave1 ##開啟bin-log日誌
log-slave-updates=ON
enforce-gtid-consistency=true ## 強制gtid複製
slave-parallel-type=LOGICAL_CLOCK ##開啟邏輯時鐘的複製
slave-parallel-workers=4 ##最大執行緒16
master_info_repository=TABLE
relay_log_info_repository=TABLE
relay_log_recovery=ON
plugin-load=rpl_semi_sync_slave=semisync_slave.so
rpl_semi_sync_slave_enabled=1
儲存退出並重啟mysql
[[email protected] mysql]# systemctl restart mysqld
授權:
mysql> grant REPLICATION SLAVE ON *.* to [email protected]'192.168.148.%' identified by '!tp!gNp667aPT';
Query OK, 0 rows affected, 1 warning (0.00 sec)
重新整理許可權
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
再加一臺slave2
slave2:配置server-id,開啟gtid
在slave2上配置server-id,開啟gtid
[[email protected] ~]# vim /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
symbolic-links=0
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
server-id=3 ##伺服器標識
binlog_format=row
gtid_mode=ON ## 開啟gtid模式
enforce-gtid-consistency=true ## 強制gtid複製
儲存並退出,重啟mysql。
-
slave1使用mysqldump全備份資料庫傳給slave2
-
在slave2上指定master為slave1
mysql>change master to master_host='192.168.148.61',
master_user='otter',
master_password='!tp!gNp667aPT',
master_auto_position=1;
mysql> start slave;
Query OK, 0 rows affected (0.01 sec)
mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State:
Master_Host: 192.168.148.61
Master_User: otter
Master_Port: 3306
Connect_Retry: 60
Master_Log_File:
Read_Master_Log_Pos: 4
Relay_Log_File: localhost-relay-bin.000001
Relay_Log_Pos: 4
Relay_Master_Log_File:
Slave_IO_Running: No
Slave_SQL_Running: Yes
##檢視狀態發現有報錯:Got fatal error 1236 from master when reading data from binary log: 'The slave is connecting using CHANGE MASTER TO MASTER_AUTO_POSITION = 1, but the master has purged binary logs containing GTIDs that the slave requires.'
-
解決方法:
- 在slave1上進行mysqldump整庫全備份,mysqldump -uroot -p密碼 -A >all.sql
- 然後開啟all.sql我們可以看到如下語句:
[[email protected] ~]# more all.sql
-- MySQL dump 10.13 Distrib 5.7.22, for Linux (x86_64)
--
-- Host: localhost Database:
-- ------------------------------------------------------
-- Server version 5.7.22-log
/*!40101 SET @[email protected]@CHARACTER_SET_CLIENT */;
/*!40101 SET @[email protected]@CHARACTER_SET_RESULTS */;
/*!40101 SET @[email protected]@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8 */;
/*!40103 SET @[email protected]@TIME_ZONE */;
/*!40103 SET TIME_ZONE='+00:00' */;
/*!40014 SET @[email protected]@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
/*!40014 SET @[email protected]@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @[email protected]@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
/*!40111 SET @[email protected]@SQL_NOTES, SQL_NOTES=0 */;
SET @MYSQLDUMP_TEMP_LOG_BIN = @@SESSION.SQL_LOG_BIN;
SET @@SESSION.SQL_LOG_BIN= 0;
--
-- GTID state at the beginning of the backup
--
SET @@GLOBAL.GTID_PURGED='4cfd948e-88c8-11e8-a94a-000c29da1af6:1-2,
4e552c02-8345-11e8-b571-000c294897b5:1-487';
--
-- Current Database: `mysql`
--
CREATE DATABASE /*!32312 IF NOT EXISTS*/ `mysql` /*!40100 DEFAULT CHARACTER SET latin1 */;
USE `mysql`;
--
-- Table structure for table `columns_priv`
--
DROP TABLE IF EXISTS `columns_priv`;
/*!40101 SET @saved_cs_client = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
SET @@GLOBAL.GTID_PURGED='4cfd948e-88c8-11e8-a94a-000c29da1af6:1-2,
4e552c02-8345-11e8-b571-000c294897b5:1-487';
此值即為slave1上gtid_executed的值。
- 在slave2上恢復slave1的備份。
mysql> source all.sql
mysql> reset master; ##在slave上做一下reset master來清除gtid的一些資訊。
Query OK, 0 rows affected (0.01 sec)
mysql> set global gtid_purged='4cfd948e-88c8-11e8-a94a-000c29da1af6:1-2,4e552c02-8345-11e8-b571-000c294897b5:1-487'; Query OK, 0 rows affected (0.00 sec)
mysql> show master status\G;
*************************** 1. row ***************************
File: mysql-bini-slave2.000001
Position: 154
Binlog_Do_DB:
Binlog_Ignore_DB:
Executed_Gtid_Set: 4cfd948e-88c8-11e8-a94a-000c29da1af6:1-2,
4e552c02-8345-11e8-b571-000c294897b5:1-487
1 row in set (0.00 sec)
ERROR:
No query specified
mysql> start slave; ##啟動slave。
Query OK, 0 rows affected (0.00 sec)
mysql> show slave status\G; ##檢視狀態恢復正常。雙YES表示恢復正常。
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.148.61
Master_User: otter
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin-slave1.000001
Read_Master_Log_Pos: 1071
Relay_Log_File: localhost-relay-bin.000002
Relay_Log_Pos: 435
Relay_Master_Log_File: mysql-bin-slave1.000001
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
master進行一條事務,slave1和slave2同步
master建立個數據庫 aaa
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| kkk |
| mysql |
| performance_schema |
| sys |
+--------------------+
5 rows in set (0.00 sec)
mysql> create database aaa;
Query OK, 1 row affected (0.01 sec)
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| aaa |
| kkk |
| mysql |
| performance_schema |
| sys |
+--------------------+
6 rows in set (0.00 sec)
slave1檢視是否同步。
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| aaa |
| kkk |
| mysql |
| performance_schema |
| sys |
+--------------------+
6 rows in set (0.01 sec)
slave2檢視是否同步。
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| aaa |
| kkk |
| mysql |
| performance_schema |
| sys |
+--------------------+
6 rows in set (0.00 sec)
七、讀寫分離
安裝MySQL中介軟體ProxySQL。
ProxySQL是用C++語言開發的,雖然也是一個輕量級產品,但效能很好(據測試,能處理千億級的資料),功能也足夠,能滿足中介軟體所需的絕大多數功能,包括:
- 最基本的讀/寫分離,且方式有多種。
- 可定製基於使用者、基於schema、基於語句的規則對SQL語句進行路由。換句話說,規則很靈活。基於schema和與語句級的規則,可以實現簡單的sharding。
- 可快取查詢結果。雖然ProxySQL的快取策略比較簡陋,但實現了基本的快取功能,絕大多數時候也夠用了。此外,作者已經打算實現更豐富的快取策略。
- 監控後端節點。ProxySQL可以監控後端節點的多個指標,包括:ProxySQL和後端的心跳資訊,後端節點的read-only/read-write,slave和master的資料同步延遲性(replication lag)。
-
注意點:slave節點需要設定read_only=1。
# 以下是slave1的配置檔案
server-id=2 ##伺服器標識
binlog_format=row
log-bin=mysql-bin-slave1
log-slave-updates=ON
gtid_mode=ON ## 開啟gtid模式
enforce-gtid-consistency=true ## 強制gtid複製
slave-parallel-type=LOGICAL_CLOCK ##開啟邏輯時鐘的複製
slave-parallel-workers=4 ##最大執行緒16
master_info_repository=TABLE
relay_log_info_repository=TABLE
relay_log_recovery=ON
plugin-load=rpl_semi_sync_slave=semisync_slave.so
rpl_semi_sync_slave_enabled=1
read_only=1
# 以下是slave2的配置檔案
server-id=3 ##伺服器標識
log-bin=mysql-bini-slave2
binlog_format=row
gtid_mode=ON ## 開啟gtid模式
enforce-gtid-consistency=true ## 強制gtid複製
read_only=1
-
安裝ProxySQL
-
以 CentOS 7 的 rpm 包為例。
cat <<EOF | tee /etc/yum.repos.d/proxysql.repo
[proxysql_repo] name= ProxySQL
baseurl=http://repo.proxysql.com/ProxySQL/proxysql-1.4.x/centos/\$releasever
gpgcheck=1 gpgkey=http://repo.proxysql.com/ProxySQL/repo_pub_key
EOF
-
然後直接安裝即可。
yum -y install proxysql
[[email protected] ~]# systemctl start proxysql ##啟動 proxysql
[[email protected] ~]# systemctl status proxysql ##檢視 proxysql狀態
Active: active (running) since 四 2018-07-19 18:04:48 CST; 40min ago
-
啟動後會監聽兩個埠,
預設為6032和6033。6032埠是ProxySQL的管理埠,6033是ProxySQL對外提供服務的埠。
[[email protected] ~]# netstat -tnlp
tcp 0 0 0.0.0.0:6032 0.0.0.0:* LISTEN 977/proxysql
tcp 0 0 0.0.0.0:6033 0.0.0.0:* LISTEN 977/proxysql
-
向ProxySQL中新增MySQL節點
然後使用mysql客戶端連線到ProxySQL的管理介面(admin interface),該介面的預設管理員使用者和密碼都是admin。
[[email protected] ~]# mysql -uadmin -padmin -P6032 -h127.0.0.1 --prompt 'admin> '
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 16
Server version: 5.5.30 (ProxySQL Admin Module)
admin> show databases;
+-----+---------------+-------------------------------------+
| seq | name | file |
+-----+---------------+-------------------------------------+
| 0 | main | |
| 2 | disk | /var/lib/proxysql/proxysql.db |
| 3 | stats | |
| 4 | monitor | |
| 5 | stats_history | /var/lib/proxysql/proxysql_stats.db |
+-----+---------------+-------------------------------------+
5 rows in set (0.00 sec)
ProxySQL提供了幾個庫,每個庫都有各自的意義。主要修改main和monitor資料庫中的表。
admin> show tables from main;
+--------------------------------------------+
| tables |
+--------------------------------------------+
| global_variables |
| mysql_collations |
| mysql_group_replication_hostgroups |
| mysql_query_rules |
| mysql_query_rules_fast_routing |
| mysql_replication_hostgroups |
| mysql_servers |
| mysql_users |
| proxysql_servers |
| runtime_checksums_values |
| runtime_global_variables |
| runtime_mysql_group_replication_hostgroups |
| runtime_mysql_query_rules |
| runtime_mysql_query_rules_fast_routing |
| runtime_mysql_replication_hostgroups |
| runtime_mysql_servers |
| runtime_mysql_users |
| runtime_proxysql_servers |
| runtime_scheduler |
| scheduler |
+--------------------------------------------+
20 rows in set (0.00 sec)
admin> show tables from monitor;
+------------------------------------+
| tables |
+------------------------------------+
| mysql_server_connect_log |
| mysql_server_group_replication_log |
| mysql_server_ping_log |
| mysql_server_read_only_log |
| mysql_server_replication_lag_log |
+------------------------------------+
5 rows in set (0.00 sec)
runtime_開頭的是執行時的配置,這些是不能修改的。要修改ProxySQL的配置,需要修改了非runtime_表,修改後必須執行LOAD ... TO RUNTIME才能載入到RUNTIME生效,執行save ... to disk才能將配置持久化儲存到磁碟。
admin> insert into mysql_servers(hostgroup_id,hostname,port) values(10,'192.168.148.62',3306);
admin> insert into mysql_servers(hostgroup_id,hostname,port) values(10,'192.168.148.61',3306);
admin> insert into mysql_servers(hostgroup_id,hostname,port) values(10,'192.168.148.64',3306);
#使用insert語句新增主機到mysql_servers表中,其中:hostgroup_id 10 表示寫組,20表示讀組。
檢視這3個節點是否插入成功,以及它們的狀態。
admin> select * from mysql_servers\G
*************************** 1. row ***************************
hostgroup_id: 10
hostname: 192.168.148.62
port: 3306
status: ONLINE
weight: 1
compression: 0
max_connections: 1000
max_replication_lag: 0
use_ssl: 0
max_latency_ms: 0
comment:
*************************** 2. row ***************************
hostgroup_id: 20
hostname: 192.168.148.61
port: 3306
status: ONLINE
weight: 1
compression: 0
max_connections: 1000
max_replication_lag: 0
use_ssl: 0
max_latency_ms: 0
comment:
*************************** 3. row ***************************
hostgroup_id: 20
hostname: 192.168.148.64
port: 3306
status: ONLINE
weight: 1
compression: 0
max_connections: 1000
max_replication_lag: 0
use_ssl: 0
max_latency_ms: 0
comment:
3 rows in set (0.00 sec)
修改後,載入到RUNTIME,並儲存到disk。
admin> load mysql servers to runtime; admin> save mysql servers to disk;
-
監控後端MySQL節點
新增節點之後,還需要監控後端節點。對於後端是主從複製的環境來說,這是必須的,因為ProxySQL需要通過每個節點的read_only值來自動調整它們是屬於讀組還是寫組。
首先在後端master節點上建立一個用於監控的使用者名稱(只需在master上建立即可,因為會複製到slave上),這個使用者名稱只需具有USAGE許可權即可。如果還需要監控複製結構中slave是否嚴重延遲於master(這個俗語叫做"拖後腿",術語叫做"replication lag"),則還需具備replication client許可權。這裡直接賦予這個許可權。
# 在master上執行:
mysql> create user [email protected]'192.168.148.%' identified by '[email protected]!'; mysql> grant replication client on *.* to [email protected]'192.168.148.%';
#然後回到ProxySQL上配置監控。
admin> set mysql-monitor_username='monitor'; admin> set mysql-monitor_password='[email protected]!';
#修改後,載入到RUNTIME,並儲存到disk。
admin> load mysql variables to runtime; admin> save mysql variables to disk;
#驗證監控結果:ProxySQL監控模組的指標都儲存在monitor庫的log表中。
以下是連線是否正常的監控(對connect指標的監控):(在前面可能會有很多connect_error,這是因為沒有配置監控資訊時的錯誤,配置後如果connect_error的結果為NULL則表示正常)
admin> select * from mysql_server_connect_log;
+----------------+------+------------------+-------------------------+---------------+
| hostname | port | time_start_us | connect_success_time_us | connect_error |
+----------------+------+------------------+-------------------------+---------------+
| 192.168.148.61 | 3306 | 1532003209576812 | 1113 | NULL |
| 192.168.148.62 | 3306 | 1532003209587641 | 428 | NULL |
| 192.168.148.64 | 3306 | 1532003209598596 | 6290 | NULL |
| 192.168.148.62 | 3306 | 1532003749593625 | 676 | NULL |
| 192.168.148.64 | 3306 | 1532003749604600 | 1459 | NULL |
+----------------+------+------------------+-------------------------+---------------+
30 rows in set (0.00 sec)
#以下是對心跳資訊的監控(對ping指標的監控):
admin> select * from mysql_server_ping_log;
+----------------+------+------------------+----------------------+------------+
| hostname | port | time_start_us | ping_success_time_us | ping_error |
+----------------+------+------------------+----------------------+------------+
| 192.168.148.61 | 3306 | 1532003210786402 | 717 | NULL |
| 192.168.148.64 | 3306 | 1532003610811775 | 382 | NULL |
| 192.168.148.61 | 3306 | 1532003620807891 | 408 | NULL |
| 192.168.148.62 | 3306 | 1532003620809610 | 140 | NULL |
| 192.168.148.64 | 3306 | 1532003800821971 | 420 | NULL |
+----------------+------+------------------+----------------------+------------+
180 rows in set (0.00 sec)
#但是,read_only和replication_lag的監控日誌都為空。
admin> select * from mysql_server_read_only_log;
Empty set (0.00 sec)
admin> select * from mysql_server_replication_lag_log;
Empty set (0.00 sec)
#例如,指定寫組的id為10,讀組的id為20。
admin> insert into mysql_replication_hostgroups values(10,20,1);
在該配置載入到RUNTIME生效之前,先檢視下各mysql server所在的組。
admin> select hostgroup_id,hostname,port,status,weight from mysql_servers;
+--------------+----------------+------+--------+--------+
| hostgroup_id | hostname | port | status | weight |
+--------------+----------------+------+--------+--------+
| 10 | 192.168.148.62 | 3306 | ONLINE | 1 |
| 10 | 192.168.148.61 | 3306 | ONLINE | 1 |
| 10 | 192.168.148.64 | 3306 | ONLINE | 1 |
+--------------+----------------+------+--------+--------+
3 rows in set (0.00 sec)
#3個節點都在hostgroup_id=10的組中。
現在,將剛才mysql_replication_hostgroups表的修改載入到RUNTIME生效。
admin> load mysql servers to runtime;
admin> save mysql servers to disk;
一載入,Monitor模組就會開始監控後端的read_only值,當監控到read_only值後,就會按照read_only的值將某些節點自動移動到讀/寫組。
例如,此處所有節點都在id=10的寫組,slave1和slave2都是slave,它們的read_only=1,這兩個節點將會移動到id=20的組。如果一開始這3節點都在id=20的讀組,那麼移動的將是Master節點,會移動到id=10的寫組。
#看結果:
admin> select hostgroup_id,hostname,port,status,weight from mysql_servers;
+--------------+----------------+------+--------+--------+
| hostgroup_id | hostname | port | status | weight |
+--------------+----------------+------+--------+--------+
| 10 | 192.168.148.62 | 3306 | ONLINE | 1 |
| 20 | 192.168.148.61 | 3306 | ONLINE | 1 |
| 20 | 192.168.148.64 | 3306 | ONLINE | 1 |
+--------------+----------------+------+--------+--------+
3 rows in set (0.00 sec)
admin> select * from mysql_server_read_only_log;
+----------------+------+------------------+-----------------+-----------+--------+
| hostname | port | time_start_us | success_time_us | read_only | error |
+----------------+------+------------------+-----------------+-----------+--------+ |
192.168.148.64 | 3306 | 1532003708480193 | 1218 | 1 | NULL |
| 192.168.148.62 | 3306 | 1532003709979095 | 2369 | 0 | NULL |
| 192.168.148.61 | 3306 | 1532003709978587 | 3464 | 1 | NULL |
| 192.168.148.64 | 3306 | 1532003709981780 | 2562 | 1 | NULL |
| 192.168.148.61 | 3306 | 1532003711479179 | 2449 | 1 | NULL |
| 192.168.148.62 | 3306 | 1532003711479965 | 1918 | 0 | NULL |
+----------------+------+------------------+-----------------+-----------+--------+ |
-
配置mysql_users
上面的所有配置都是關於後端MySQL節點的,現在可以配置關於SQL語句的,包括:傳送SQL語句的使用者、SQL語句的路由規則、SQL查詢的快取、SQL語句的重寫等等。本小節是SQL請求所使用的使用者配置,例如root使用者。這要求我們需要先在後端MySQL節點新增好相關使用者。這裡以root和sqlsender兩個使用者名稱為例。
#首先,在master節點上執行:(只需master執行即可,會複製給兩個slave)
mysql> grant all on *.* to [email protected]'192.168.148.%' identified by 'passwd';
mysql> grant all on *.* to [email protected]'192.168.148.%' identified by '[email protected]!';
#然後回到ProxySQL,配置mysql_users表,將剛才的兩個使用者新增到該表中。
admin> insert into mysql_users(username,password,default_hostgroup) values('root','passwd',10);
admin> insert into mysql_users(username,password,default_hostgroup) values('sqlsender','[email protected]!',10);
admin> load mysql users to runtime; admin> save mysql users to disk;
mysql_users表有不少欄位,最主要的三個欄位為username、password和default_hostgroup:
- username:前端連線ProxySQL,以及ProxySQL將SQL語句路由給MySQL所使用的使用者名稱。
- password:使用者名稱對應的密碼。可以是明文密碼,也可以是hash密碼。如果想使用hash密碼,可以先在某個MySQL節點上執行select password(PASSWORD),然後將加密結果複製到該欄位。
- default_hostgroup:該使用者名稱預設的路由目標。例如,指定root使用者的該欄位值為10時,則使用root使用者傳送的SQL語句預設情況下將路由到hostgroup_id=10組中的某個節點。
admin> select * from mysql_users\G
*************************** 1. row ***************************
username: root
password: passwd
active: 1
use_ssl: 0
default_hostgroup: 10
default_schema: NULL
schema_locked: 0
transaction_persistent: 1
fast_forward: 0
backend: 1
frontend: 1
max_connections: 10000
*************************** 2. row ***************************
username: sqlsender
password: [email protected]!
active: 1
use_ssl: 0