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mysql數據;本次要介紹的是mysql的主從復制,讀寫分離;及高可用MHA;
環境如下:
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
架構圖:
說明:
配置測試時為了方便關閉了防火墻頭,selinux安全策略;
現實中請開放防火墻策略;myslqdb的安裝已經有腳本一鍵安裝并配置好;這里就不在重復配置;只對對應的角色貼出對應的配置或安裝與之相關的軟件;
二、主從復制配置
一臺主數據庫,N從節點;從節點開啟兩個線程,通過Slave_IO_Running線程和主節點上有權限的賬號從 主數據庫節點復制binlog日志到本地,能過Slave_SQL_Running線程在本地執行binlog日志,達到主從節點內容同步;
master配置:
egrep -v '(^$|^#)' /usr/local/mysql/etc/my.cnf
[mysqld]
datadir=/data1/mysqldb
socket=/tmp/mysql.sock
key_buffer_size = 16M
max_allowed_packet = 16M
thread_stack = 192K
thread_cache_size = 8
query_cache_limit = 1M
query_cache_size = 64M
query_cache_type = 1
symbolic-links=0
innodb_file_per_table=ON
skip_name_resolve=ON
server-id = 1
log_bin = /data1/mysqldb/mysql-bin.log
[mysqld_safe]
log-error=/usr/local/mysql/logs/error.log
pid-file=/data1/mysqldb/mysql.pid
!includedir /usr/local/mysql/etc/my.cnf.d
創建從節點同步賬號:
mysql > grant replication client,replication slave on *.* to 'repluser'@'172.16.3.%' identified by 'replpass';
mysql > flush privileges;
mysql >show master logs;
+------------------+-----------+
| Log_name | File_size |
+------------------+-----------+
| mysql-bin.000001 | 622 |
主節點上的binlog日志文件及位置;請記下;從節點第一次同步時需要用;
slave節點:
egrep -v '(^$|^#)' /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 #從節點標識ID 各從節點均不一樣
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數據庫
注意:兩臺從節點的server-id 值不一樣;其他的都一樣;因此從節點只展示一個配置文件;
登錄數據庫并同步數據啟動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; #啟動從節點()
#查看從節點狀態
mysql > SHOW SLAVE STATUS;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 172.16.3.175 #主節點
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導入測試數據;修改數據并查看slave 中的數據是否一致;
[root@db1 ~]# mysql Testdb.sql
登錄數據庫
[root@db1 ~]# mysql -uroot -p
mysql> show databases;
+--------------------+
| Database |
+--------------------+
study |
+--------------------+
5 rows in set (0.00 sec)
###study測試數據庫導入成功
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)
數據已經可以正常同步;注意主從同步只需要第一次手動啟動;之后都隨mysql服務自動啟動;主從同步架構只方便了數據的同步,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,就需要手動同步數據；這里通過proxysql來做讀寫分離;
三、proxysql之讀寫分離
以上已經完成了主從復制配置;然而這只是一個基本配置,加上一個proxysql實現mysql讀寫分離,proxysql類似haproxy七層代理路由功能且支持MySQL 協議的的數據庫代理；是dba開發給dba使用的;用戶請求發向proxysql,如果是寫請求發往主節點;讀請求發下從節點組中;以此實現讀寫分離;一定程序上減輕了主數據庫的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之前需要在主節點配置授權賬號以作proxysql對主從節點操作;另外proxysql上的mysql客戶端工具需要和主從節點上的保持一致;
在主節點master上授權登錄賬號：
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,建議和cpu核心數一致
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" #注釋內容
}
)
啟動proxysql服務
[root@proxysql ~]# service proxysql start
測試proxysql
模擬通過proxysql使用數據庫
[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數據庫user_info中6 -12之間的數據
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)
到主從節點上查看,會發現以上的查和修改數據都被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與各主從節點通訊我們在主從節點上安裝tcpdump并過濾包
主節點:
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據庫;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主從復制讀寫分離架構已經完成;
雙主或多主模型是無須實現讀寫分離，僅需要負載均衡：haproxy, nginx, lvs等;
proxysql并沒有解決,當主數據巖機時的問題;此時就需要量MHA來解決 ;后續再介紹;
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