mysql主从复制读写分离与高可用配置

一、说明

前面我们说了mysql的安装配置(并提供一键安装脚本),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;MASTER_CONNECT_RETRY=10,MASTER_HEARTBEAT_PERIOD=2; 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.cnf

datadir="/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 -h272.16.3.175 -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;更多命令行的配置请参考github;

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;