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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 ‘(^$|^#)’ /usr/local/mysql/etc/my.cnf
[mysqld]
datadir=/data1/mysqldb
socket=/tmp/mysql.sock
key_buffer_size = 16M
max_allowed_packet = 16M
thread_stack = 192K
thread_cache_size = 8
query_cache_limit = 1M
query_cache_size = 64M
query_cache_type = 1
symbolic-links=0
innodb_file_per_table=ON
skip_name_resolve=ON
server-id = 1
log_bin = /data1/mysqldb/mysql-bin.log
[mysqld_safe]
log-error=/usr/local/mysql/logs/error.log
pid-file=/data1/mysqldb/mysql.pid
!includedir /usr/local/mysql/etc/my.cnf.d
创建从节点同步账号:
mysql > grant replication client,replication slave on *.* to ‘repluser’@’172.16.3.%’ identified by ‘replpass’;
mysql > flush privileges;
mysql >show master logs;
+——————+———–+
| Log_name | File_size |
+——————+———–+
| mysql-bin.000001 | 622 |
主节点上的 binlog 日志文件及位置; 请记下; 从节点第一次同步时需要用;
slave 节点:
egrep -v ‘(^$|^#)’ /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���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)
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)
### 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 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;