mysql主从复制读写分离的配置方法详解

一、说明

前面我们说了mysql/' target='_blank'>mysql的安装配置,MySQL语句使用以及备份恢复mysql数据;本次要介绍的是mysql的主从复制,读写分离;及高可用MHA;

环境如下:

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

架构图:

说明:

配置测试时为了方便关闭了防火墙头,selinux安全策略;
现实中请开放防火墙策略;myslqdb的安装已经有脚本一键安装并配置好;这里就不在重复配置;只对对应的角色贴出对应的配置或安装与之相关的软件;

二、主从复制配置

一台主数据库,N从节点;从节点开启两个线程,通过Slave_IO_Running线程和主节点上有权限的账号从 主数据库节点复制binlog日志到本地,能过Slave_SQL_Running线程在本地执行binlog日志,达到主从节点内容同步;

master配置:

egrep -v '(^$|^#)' /usr/local/mysql/etc/my.cnf[mysqld]datadir=/data1/mysqldbsocket=/tmp/mysql.sockkey_buffer_size   = 16Mmax_allowed_packet  = 16Mthread_stack   = 192Kthread_cache_size  = 8query_cache_limit  = 1Mquery_cache_size  = 64Mquery_cache_type  = 1symbolic-links=0innodb_file_per_table=ONskip_name_resolve=ONserver-id  = 1log_bin   = /data1/mysqldb/mysql-bin.log[mysqld_safe]log-error=/usr/local/mysql/logs/error.logpid-file=/data1/mysqldb/mysql.pid!includedir /usr/local/mysql/etc/my.cnf.d

创建从节点同步账号:

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 |

主节点上的binlog日志文件及位置;请记下;从节点第一次同步时需要用;

slave节点:

egrep -v '(^$|^#)' /usr/local/mysql/etc/my.cnf[mysqld]datadir=/data1/mysqldbsocket=/data1/mysqldb/mysql.sockkey_buffer_size   = 16Mmax_allowed_packet  = 16Mthread_stack   = 192Kthread_cache_size  = 8query_cache_limit  = 1Mquery_cache_size  = 64Mquery_cache_type  = 1symbolic-links=0innodb_file_per_table=ONskip_name_resolve=ONserver-id    = 11   #从节点标识ID 各从节点均不一样 relay_log = relay-logread_only=ON[mysqld_safe]log-error=/usr/local/mysql/log/error.logpid-file=/var/run/mysql/mysql.pid!includedir /usr/local/mysql/etc/my.cnf.d

启动mysq数据库

注意:两台从节点的server-id 值不一样;其他的都一样;因此从节点只展示一个配置文件;
登录数据库并同步数据启动slave

两台slave均要同步并启动

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;  #启动从节点()#查看从节点状态mysql > SHOW SLAVE STATUS;*************************** 1. row ***************************    Slave_IO_State: Waiting for master to send event     Master_Host: 172.16.3.175     #主节点     Master_User: repluser       #同步账号     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      #同步线程正常   Slave_SQL_Running: Yes     #本地写线程正常    Replicate_Do_DB:        #同步过滤为空(可以只同步某个或某些库)   Replicate_Ignore_DB:        #不同步的库   Replicate_Do_Table:        Replicate_Ignore_Table:   Replicate_Wild_Do_Table:  Replicate_Wild_Ignore_Table:      Last_Errno: 0    #最后同步的错误 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: 0Master_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

测试主从同步

在master导入测试数据;修改数据并查看slave 中的数据是否一致;

[root@db1 ~]# mysql < Testdb.sql登录数据库[root@db1 ~]# mysql -uroot -pmysql> show databases;+--------------------+| Database   |+--------------------+ study    |+--------------------+5 rows in set (0.00 sec)###study测试数据库导入成功mysql> use study;Database changedmysql> show tables;+-----------------+| Tables_in_study |+-----------------+| class   || course   || part   || score   || student   || tb31   || tb32   || teacher   || test1   || test2   || user_info  |+-----------------+11 rows in set (0.00 sec)#删除test1 test2表

slave从节点上查看

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

数据已经可以正常同步;注意主从同步只需要第一次手动启动;之后都随mysql服务自动启动;主从同步架构只方便了数据的同步,此时如果没有 第三方工具介入想做到读写分离就需要在程序中去做,难免出错;而出错了,就需要手动同步数据；这里通过proxysql来做读写分离;

三、proxysql之读写分离

以上已经完成了主从复制配置;然而这只是一个基本配置,加上一个proxysql实现mysql读写分离,proxysql类似haproxy七层代理路由功能且支持MySQL 协议的的数据库代理；是dba开发给dba使用的;用户请求发向proxysql,如果是写请求发往主节点;读请求发下从节点组中;以此实现读写分离;一定程序上减轻了主数据库的io压力;
下载安装proxysql
目前最新版本是1.4.7-1(由于最新版本有问题)
我们这里下载使用1.3.6-1的基于CentOS7的rpm包;下载到本地并yum安装

[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之前需要在主节点配置授权账号以作proxysql对主从节点操作;另外proxysql上的mysql客户端工具需要和主从节点上的保持一致;
在主节点master上授权登录账号：

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

proxysql.cnf配置

[root@proxysql ~]# egrep -v '(^$|^#)' /etc/proxysql.cnfdatadir="/var/lib/proxysql"admin_variables={  admin_credentials="admin:admin"    #proxysql自己的管理用户名密码 mysql_ifaces="127.0.0.1:6032;/tmp/proxysql_admin.sock"}mysql_variables={ threads=4       #线程数,建议和cpu核心数一致 max_connections=2048  #最大连接 default_query_delay=0 default_query_timeout=36000000 have_compress=true poll_timeout=2000 interfaces="0.0.0.0:3306;/tmp/proxysql.sock"    #对外接口 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}#####主从节点的配置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   # 设置组号  status = "ONLINE"  # default: ONLINE  weight = 1   # default: 1  compression = 0  # default: 0  max_connections = 200   ###定义最大的连接 }, {  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   #定义写组号1    reader_hostgroup=2  #定义读组号2    comment="test repl 1" #注释内容  })

启动proxysql服务

[root@proxysql ~]# service proxysql start

测试proxysql

模拟通过proxysql使用数据库[root@proxysql ]# mysql -h172.16.3.175 -umyadmin -pmypassmysql: [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 17406Server 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 itsaffiliates. Other names may be trademarks of their respectiveowners.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)###删除study数据库user_info中6 -12之间的数据删除之前: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)删除之后: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)

到主从节点上查看,会发现以上的查和修改数据都被proxysql正确的代理到后端处理了;
以上看了并不直观;为了查看proxysql与各主从节点通讯我们在主从节点上安装tcpdump并过滤包

主节点:类似如下:[root@db1 ~]# tcpdump -i enp0s3 -nn tcp port 3306tcpdump: verbose output suppressed, use -v or -vv for full protocol decodelistening on enp0s3, link-type EN10MB (Ethernet), capture size 262144 bytes18:04:34.678861 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 018:04:34.678908 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 018:04:34.680902 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 018:04:34.681264 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....从节点:类似如下:[root@db2 data1]# tcpdump -i enp0s3 -nn tcp port 3306tcpdump: verbose output suppressed, use -v or -vv for full protocol decodelistening on enp0s3, link-type EN10MB (Ethernet), capture size 262144 bytes18:02:57.932043 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:支持运行时修改

 [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都从配置文件中获取的数据库;可以通过类似mysql运行时修改;而不需要重启;

至此我们基于proxysql主从复制读写分离架构已经完成;
双主或多主模型是无须实现读写分离，仅需要负载均衡：haproxy, nginx, lvs等;
proxysql并没有解决,当主数据岩机时的问题;此时就需要量MHA来解决 ;后续再介绍;