mysql主從復(fù)制讀寫分離的配置方法詳解

更新時間：2018年04月09日 08:57:13 作者：dyc2005

一般來說mysql都是通過主從復(fù)制（Master-Slave）的方式來同步數(shù)據(jù)，再通過讀寫分離（MySQL-Proxy）來提升數(shù)據(jù)庫的并發(fā)負(fù)載能力這樣的方案來進(jìn)行部署與實施的。

一、說明

前面我們說了mysql的安裝配置,mysql語句使用以及備份恢復(fù)mysql數(shù)據(jù);本次要介紹的是mysql的主從復(fù)制,讀寫分離;及高可用MHA;

環(huán)境如下:

master:CentOS7_x64 mysql5.721 172.16.3.175 db1
slave1:CentOS7_x64 mysql5.7.21 172.16.3.235 db2
slave2:CentOS7_x64 mysql5.7.21 172.16.3.235 db3
proxysql/MHA:CentOS7_x64 mysql5.7.21 172.16.3.235 proxysql

架構(gòu)圖:

說明:

配置測試時為了方便關(guān)閉了防火墻頭,selinux安全策略;
現(xiàn)實中請開放防火墻策略;myslqdb的安裝已經(jīng)有腳本一鍵安裝并配置好;這里就不在重復(fù)配置;只對對應(yīng)的角色貼出對應(yīng)的配置或安裝與之相關(guān)的軟件;

二、主從復(fù)制配置

一臺主數(shù)據(jù)庫,N從節(jié)點;從節(jié)點開啟兩個線程,通過Slave_IO_Running線程和主節(jié)點上有權(quán)限的賬號從主數(shù)據(jù)庫節(jié)點復(fù)制binlog日志到本地,能過Slave_SQL_Running線程在本地執(zhí)行binlog日志,達(dá)到主從節(jié)點內(nèi)容同步;

master配置:

egrep -v '(^$|^#)' /usr/local/mysql/etc/my.cnf

[mysqld]
datadir=/data1/mysqldb
socket=/tmp/mysql.sock
key_buffer_size   = 16M
max_allowed_packet  = 16M
thread_stack   = 192K
thread_cache_size  = 8
query_cache_limit  = 1M
query_cache_size  = 64M
query_cache_type  = 1
symbolic-links=0
innodb_file_per_table=ON
skip_name_resolve=ON

server-id  = 1
log_bin   = /data1/mysqldb/mysql-bin.log
[mysqld_safe]
log-error=/usr/local/mysql/logs/error.log
pid-file=/data1/mysqldb/mysql.pid
!includedir /usr/local/mysql/etc/my.cnf.d

創(chuàng)建從節(jié)點同步賬號:

mysql > grant replication client,replication slave on *.* to 'repluser'@'172.16.3.%' identified by 'replpass';
mysql > flush privileges;
mysql >show master logs;
+------------------+-----------+
| Log_name   | File_size |
+------------------+-----------+
| mysql-bin.000001 |  622 |

主節(jié)點上的binlog日志文件及位置;請記下;從節(jié)點第一次同步時需要用;

slave節(jié)點:

egrep -v '(^$|^#)' /usr/local/mysql/etc/my.cnf

[mysqld]
datadir=/data1/mysqldb
socket=/data1/mysqldb/mysql.sock
key_buffer_size   = 16M
max_allowed_packet  = 16M
thread_stack   = 192K
thread_cache_size  = 8
query_cache_limit  = 1M
query_cache_size  = 64M
query_cache_type  = 1
symbolic-links=0

innodb_file_per_table=ON
skip_name_resolve=ON

server-id    = 11   #從節(jié)點標(biāo)識ID 各從節(jié)點均不一樣 
relay_log = relay-log
read_only=ON

[mysqld_safe]
log-error=/usr/local/mysql/log/error.log
pid-file=/var/run/mysql/mysql.pid
!includedir /usr/local/mysql/etc/my.cnf.d

啟動mysq數(shù)據(jù)庫

注意:兩臺從節(jié)點的server-id 值不一樣;其他的都一樣;因此從節(jié)點只展示一個配置文件;
登錄數(shù)據(jù)庫并同步數(shù)據(jù)啟動slave

兩臺slave均要同步并啟動

mysql > CHANGE MASTER TO MASTER_HOST="172.16.3.175",MASTER_USER="repluser",MASTER_PASSWORD="replpass",MASTER_PORT=3306,MASTER_LOG_FILE="mysql-bin.000001",MASTER_LOG_POS=622;
mysql > start slave;  #啟動從節(jié)點()

#查看從節(jié)點狀態(tài)
mysql > SHOW SLAVE STATUS;
*************************** 1. row ***************************
    Slave_IO_State: Waiting for master to send event
     Master_Host: 172.16.3.175     #主節(jié)點
     Master_User: repluser       #同步賬號
     Master_Port: 3306
    Connect_Retry: 60
    Master_Log_File: mysql-bin.000001
   Read_Master_Log_Pos: 622
    Relay_Log_File: relay-log.000001
    Relay_Log_Pos: 582
  Relay_Master_Log_File: mysql-bin.000001
    Slave_IO_Running: Yes      #同步線程正常
   Slave_SQL_Running: Yes     #本地寫線程正常
    Replicate_Do_DB:        #同步過濾為空(可以只同步某個或某些庫)
   Replicate_Ignore_DB:        #不同步的庫
   Replicate_Do_Table:      
  Replicate_Ignore_Table: 
  Replicate_Wild_Do_Table: 
 Replicate_Wild_Ignore_Table: 
     Last_Errno: 0    #最后同步的錯誤 0表示正常同步
     Last_Error: 
     Skip_Counter: 0
   Exec_Master_Log_Pos: 622
    Relay_Log_Space: 615
    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
     Master_UUID: 57017c43-36e3-11e8-ac76-080027393fc7
    Master_Info_File: /data1/mysqldb/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

測試主從同步

在master導(dǎo)入測試數(shù)據(jù);修改數(shù)據(jù)并查看slave 中的數(shù)據(jù)是否一致;

[root@db1 ~]# mysql < Testdb.sql
登錄數(shù)據(jù)庫
[root@db1 ~]# mysql -uroot -p
mysql> show databases;
+--------------------+
| Database   |
+--------------------+
 study    |
+--------------------+
5 rows in set (0.00 sec)
###study測試數(shù)據(jù)庫導(dǎo)入成功
mysql> use study;
Database changed
mysql> show tables;
+-----------------+
| Tables_in_study |
+-----------------+
| class   |
| course   |
| part   |
| score   |
| student   |
| tb31   |
| tb32   |
| teacher   |
| test1   |
| test2   |
| user_info  |
+-----------------+
11 rows in set (0.00 sec)
#刪除test1 test2表

slave從節(jié)點上查看

mysql> show tables;
+-----------------+
| Tables_in_study |
+-----------------+
| class   |
| course   |
| part   |
| score   |
| student   |
| tb31   |
| tb32   |
| teacher   |
| user_info  |
+-----------------+
9 rows in set (0.00 sec)

數(shù)據(jù)已經(jīng)可以正常同步;注意主從同步只需要第一次手動啟動;之后都隨mysql服務(wù)自動啟動;主從同步架構(gòu)只方便了數(shù)據(jù)的同步,此時如果沒有第三方工具介入想做到讀寫分離就需要在程序中去做,難免出錯;而出錯了,就需要手動同步數(shù)據(jù)；這里通過proxysql來做讀寫分離;

三、proxysql之讀寫分離

以上已經(jīng)完成了主從復(fù)制配置;然而這只是一個基本配置,加上一個proxysql實現(xiàn)mysql讀寫分離,proxysql類似haproxy七層代理路由功能且支持MySQL 協(xié)議的的數(shù)據(jù)庫代理；是dba開發(fā)給dba使用的;用戶請求發(fā)向proxysql,如果是寫請求發(fā)往主節(jié)點;讀請求發(fā)下從節(jié)點組中;以此實現(xiàn)讀寫分離;一定程序上減輕了主數(shù)據(jù)庫的io壓力;
下載安裝proxysql
目前最新版本是1.4.7-1(由于最新版本有問題)
我們這里下載使用1.3.6-1的基于CentOS7的rpm包;下載到本地并yum安裝

[root@proxysql ~]# yum install proxysql-1.3.6-1-centos7.x86_64.rpm -y
[root@proxysql ~]# rpm -ql proxysql
/etc/init.d/proxysql
/etc/proxysql.cnf  #主配置文件
/usr/bin/proxysql
/usr/share/proxysql/tools/proxysql_galera_checker.sh
/usr/share/proxysql/tools/proxysql_galera_writer.pl

配置如下:

在配置proxysql之前需要在主節(jié)點配置授權(quán)賬號以作proxysql對主從節(jié)點操作;另外proxysql上的mysql客戶端工具需要和主從節(jié)點上的保持一致;
在主節(jié)點master上授權(quán)登錄賬號：

mysql > GRANT ALL ON *.* TO 'myadmin'@'172.16.3.%' identified by 'mypass';

proxysql.cnf配置

[root@proxysql ~]# egrep -v '(^$|^#)' /etc/proxysql.cnf

datadir="/var/lib/proxysql"
admin_variables=
{ 
 admin_credentials="admin:admin"    #proxysql自己的管理用戶名密碼
 mysql_ifaces="127.0.0.1:6032;/tmp/proxysql_admin.sock"
}
mysql_variables=
{
 threads=4       #線程數(shù),建議和cpu核心數(shù)一致
 max_connections=2048  #最大連接
 default_query_delay=0
 default_query_timeout=36000000
 have_compress=true
 poll_timeout=2000
 interfaces="0.0.0.0:3306;/tmp/proxysql.sock"    #對外接口
 default_schema="information_schema"
 stacksize=1048576
 server_version="5.5.30"
 connect_timeout_server=3000
 monitor_username="monitor"
 monitor_password="monitor"
 monitor_history=600000
 monitor_connect_interval=60000
 monitor_ping_interval=10000
 monitor_read_only_interval=1500
 monitor_read_only_timeout=500
 ping_interval_server_msec=120000
 ping_timeout_server=500
 commands_stats=true
 sessions_sort=true
 connect_retries_on_failure=10
}

#####主從節(jié)點的配置
mysql_servers =      
(
 {
  address = "172.16.3.175" # no default, required . If port is 0 , address is interpred as a Unix Socket Domain
  port = 3306   # no default, required . If port is 0 , address is interpred as a Unix Socket Domain
  hostgroup = 1   # 設(shè)置組號
  status = "ONLINE"  # default: ONLINE
  weight = 1   # default: 1
  compression = 0  # default: 0
  max_connections = 200   ###定義最大的連接
 },
 {
  address = "172.16.3.235" # no default, required . If port is 0 , address is interpred as a Unix Socket Domain
  port = 3306   # no default, required . If port is 0 , address is interpred as a Unix Socket Domain
  hostgroup = 2   # no default, required
  status = "ONLINE"  # default: ONLINE
  weight = 1   # default: 1
  compression = 0  # default: 0
  max_connections=1000
 },
 {
  address = "172.16.3.241" # no default, required . If port is 0 , address is interpred as a Unix Socket Domain
  port = 3306   # no default, required . If port is 0 , address is interpred as a Unix Socket Domain
  hostgroup = 2   # no default, required
  status = "ONLINE"  # default: ONLINE
  weight = 1   # default: 1
  compression = 0  # default: 0
  max_connections=1000
 }
)
mysql_users:
(
 {
  username = "myadmin" # no default , required
  password = "mypass" # default: ''
  default_hostgroup = 1 # default: 0
  max_connections=1000
  default_schema="test"
  active = 1   #是否激活
 }
)
mysql_query_rules:
(
)
scheduler=
(
)
mysql_replication_hostgroups=
(
  {
    writer_hostgroup=1   #定義寫組號1
    reader_hostgroup=2  #定義讀組號2
    comment="test repl 1" #注釋內(nèi)容
  }
)

啟動proxysql服務(wù)

[root@proxysql ~]# service proxysql start

測試proxysql

模擬通過proxysql使用數(shù)據(jù)庫
[root@proxysql ]# mysql -h172.16.3.175 -umyadmin -pmypass
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 17406
Server version: 5.7.21-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> 

mysql > show databases;
mysql> show databases;
+--------------------+
| Database   |
+--------------------+
| information_schema |
| mysql    |
| performance_schema |
| study    |
| sys    |
+--------------------+
5 rows in set (0.00 sec)
###刪除study數(shù)據(jù)庫user_info中6 -12之間的數(shù)據(jù)
刪除之前:
mysql> select * from user_info;
+-----+-------+------+--------+----------+
| nid | name | age | gender | part_nid |
+-----+-------+------+--------+----------+
| 1 | san | 20 | 男  |  1 |
| 2 | dong | 29 | 男  |  2 |
| 4 | Ling | 28 | 男  |  4 |
| 5 | ling | 28 | 男  |  3 |
| 6 | dong | 30 | 男  |  1 |
| 7 | b  | 11 | 女  |  1 |
| 8 | c  | 12 | 女  |  1 |
| 9 | d  | 18 | 女  |  4 |
| 10 | e  | 22 | 男  |  3 |
| 11 | f  | 23 | 男  |  2 |
| 12 | dongy | 22 | 男  |  1 |
+-----+-------+------+--------+----------+
11 rows in set (0.00 sec)
刪除之后:
mysql> delete from user_info where nid >6 and nid <12;
Query OK, 5 rows affected (0.03 sec)

mysql> select * from user_info;
+-----+-------+------+--------+----------+
| nid | name | age | gender | part_nid |
+-----+-------+------+--------+----------+
| 1 | san | 20 | 男  |  1 |
| 2 | dong | 29 | 男  |  2 |
| 4 | Ling | 28 | 男  |  4 |
| 5 | ling | 28 | 男  |  3 |
| 6 | dong | 30 | 男  |  1 |
| 12 | dongy | 22 | 男  |  1 |
+-----+-------+------+--------+----------+
6 rows in set (0.00 sec)

到主從節(jié)點上查看,會發(fā)現(xiàn)以上的查和修改數(shù)據(jù)都被proxysql正確的代理到后端處理了;
以上看了并不直觀;為了查看proxysql與各主從節(jié)點通訊我們在主從節(jié)點上安裝tcpdump并過濾包

主節(jié)點:
類似如下:
[root@db1 ~]# tcpdump -i enp0s3 -nn tcp port 3306
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on enp0s3, link-type EN10MB (Ethernet), capture size 262144 bytes
18:04:34.678861 IP 172.16.3.254.42191 > 172.16.3.175.3306: Flags [S], seq 3385407732, win 29200, options [mss 1460,sackOK,TS val 17576713 ecr 0,nop,wscale 7], length 0
18:04:34.678908 IP 172.16.3.175.3306 > 172.16.3.254.42191: Flags [S.], seq 1579426335, ack 3385407733, win 28960, options [mss 1460,sackOK,TS val 29413673 ecr 17576713,nop,wscale 7], length 0
18:04:34.680902 IP 172.16.3.254.42191 > 172.16.3.175.3306: Flags [.], ack 1, win 229, options [nop,nop,TS val 17576715 ecr 29413673], length 0
18:04:34.681264 IP 172.16.3.175.3306 > 172.16.3.254.42191: Flags [P.], seq 1:83, ack 1, win 227, options [nop,nop,TS val 29413675 ecr 17576715], length 82
....
從節(jié)點:
類似如下:
[root@db2 data1]# tcpdump -i enp0s3 -nn tcp port 3306
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on enp0s3, link-type EN10MB (Ethernet), capture size 262144 bytes
18:02:57.932043 IP 172.16.3.254.42733 > 172.16.3.235.3306: Flags [S], seq 76520456, win 29200, options [mss 1460,sackOK,TS val 17479189 ecr 0,nop,wscale 7], length 0
...........

proxysql命令行管理接口:支持運行時修改

 [root@proxysql]# mysql -u admin -padmin -h 127.0.0.1 -P6032 --prompt='Admin> '
Admin> show databases;
+-----+---------+-------------------------------+
| seq | name | file       |
+-----+---------+-------------------------------+
| 0 | main |        |
| 2 | disk | /var/lib/proxysql/proxysql.db |
| 3 | stats |        |
| 4 | monitor |        |
+-----+---------+-------------------------------+
4 rows in set (0.00 sec)

以上stats,monitor,main都從配置文件中獲取的數(shù)據(jù)庫;可以通過類似mysql運行時修改;而不需要重啟;

至此我們基于proxysql主從復(fù)制讀寫分離架構(gòu)已經(jīng)完成;
雙主或多主模型是無須實現(xiàn)讀寫分離，僅需要負(fù)載均衡：haproxy, nginx, lvs等;
proxysql并沒有解決,當(dāng)主數(shù)據(jù)巖機(jī)時的問題;此時就需要量MHA來解決 ;后續(xù)再介紹;

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