mysql主从复制读写分离与高可用配置-原创手记-慕课网

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:

mysql主从复制读写分离与高可用配置

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/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

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/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 #从节点标识ID 各从节点均不一样

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

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: 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

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 -p

mysql> 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 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)

#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 -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)

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)

###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;

+-----+-------+------+--------+----------+

+-----+-------+------+--------+----------+

| 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;

+-----+-------+------+--------+----------+

+-----+-------+------+--------+----------+

| 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 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

....

从节点:

类似如下:

[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;