MySQL 5.6通过Keepalived+互为主从实现高可用架构

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本文将介绍两台mysql如何实现高可用架构。通常我们会配置主从同步,但这样若主的Mysql挂掉,还需要手动干预,例如把指向主库的IP地址修改为指向从库的IP,为了实现自动切换到从数据库,我们可以使用Keepalived配置一个浮动的VIP出来供前端访问,主的Mysql故障了VIP会立即自动切换到从的Mysql,省去了人工干预的时间,但要想故障的那台Mysql起来后也能作为从Mysql自动去同步数据,就需要配置成互为主从。拥有VIP的Mysql可认为是主库,才能进行数据的写入,由于VIP可以在两台Mysql之间浮动切换,因此这两台mysql是互为主从。

一、测试环境

操作系统版本:Red Hat Enterprise Linux Server release 6.5 (Santiago)

Mysql版本:MySQL-5.6.38-1.el6.x86_64.rpm-bundle.tar

keepalived版本:keepalived-1.2.7-3.el6.x86_64.rpm

node01:192.168.10.71

node02:192.168.10.72

VIP:192.168.10.70


二、配置node01为主、node02为从的主从同步

1、node01和node02分别安装好Mysql 5.6.38,安装方法请参考上一篇博文MySQL 5.6.38在RedHat 6.5上通过RPM包安装


2、在node01和node02分别编辑/etc/my.cnf,配置如下:

[mysqld]

log-bin=mysql-bin

server-id = 1


[mysqld_safe]

log-error = /var/log/mysqld.log

pid-file = /var/run/mysqld/mysqld.pid

replicate-do-db = all


3、重启mysql服务

[[email protected] ~]# service mysql restart

[[email protected] ~]# service mysql restart


4、登录node01的mysql,创建用于同步的账户repl,密码为123456,并查询master状态,记下file名称和posttion数值

mysql> GRANT REPLICATION SLAVE ON *.* to ‘repl‘@‘%‘ identified by ‘123456‘;

Query OK, 0 rows affected (0.00 sec)

mysql> show master status;

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5、登录node02的mysql,执行以下语句开启从服务器,注意master_host要填写node01的IP

mysql> change master to master_host=‘192.168.10.71‘,master_user=‘repl‘,master_password=‘123456‘,master_log_file=‘mysql-bin.000001‘,master_log_pos=318;

Query OK, 0 rows affected, 2 warnings (0.36 sec)

命令参数解释:
master_host=‘192.168.10.71‘ ## Master 的 IP 地址
master_user=‘repl‘ ## 用于同步数据的用户(在 Master中授权的用户)
master_password=‘123456‘ ## 同步数据用户的密码
master_log_file=‘mysql-bin.000001‘ ##指定 Slave 从哪个日志文
件开始读复制数据(可在 Master 上使用 show master status 查看到日志文件名)
master_log_pos=429  ## 从哪个 POSITION 号开始读


mysql> start slave;

Query OK, 0 rows affected (0.03 sec)


6、查询从服务的状态,状态正常

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7、在node01创建一个数据库、一个表并插入一行数据,用于测试node02是否能同步过去

mysql> create database mysql_long;

Query OK, 1 row affected (0.00 sec)


mysql> use mysql_long;

Database changed


mysql> create table test(id int(3),name char(5));

Query OK, 0 rows affected (0.13 sec)


mysql> insert into test values (001,‘jlong‘);

Query OK, 1 row affected (0.01 sec)

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8、登录到node02的Mysql,同步正常

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三、配置node02为主、node01为从的主从同步

1、登录node02的mysql,创建用于同步的账户repl,密码为123456,并查询master状态,记下file名称和posttion数值,并查询master状态

mysql> GRANT REPLICATION SLAVE ON *.* to ‘repl‘@‘%‘ identified by ‘123456‘;

Query OK, 0 rows affected (0.00 sec)

Query OK, 0 rows affected (0.10 sec)


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2、登录node01的mysql,执行以下语句开启从服务器,注意这里master_host要填写node02的IP

mysql> change master to master_host=‘192.168.10.72‘,master_user=‘repl‘,master_password=‘123456‘,master_log_file=‘mysql-bin.000001‘,master_log_pos=318;

Query OK, 0 rows affected, 2 warnings (0.36 sec)


mysql> start slave;

Query OK, 0 rows affected (0.03 sec)


3、查询从服务的状态,状态正常

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4、在node02创建一个数据库、一个表并插入一行数据,用于测试node01是否能同步过去

mysql> create database mysql_long2;

Query OK, 1 row affected (0.00 sec)


mysql> use mysql_long2;

Database changed


mysql> create table test2(id int(3),name char(10));

Query OK, 0 rows affected (0.71 sec)


mysql> insert into test2 values (001,‘jianlong‘);


Query OK, 1 row affected (0.00 sec

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5、node01同步正常。

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这样互为主从就配置好了,两台机既是对方的Master,又是对方的Slave,无论在哪一台机上数据发生了变化,另一台都能及时进行同步数据,下面我们开始配置keepalived实现高可用。


四、keepalived配置

1、在node01上使用yum安装keepalived

[[email protected] ~]# yum install keepalived -y

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2、在node02上也使用yum安装keepalived

[[email protected] ~]# yum install keepalived -y

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3、编辑node01的keepalived的配置文件

[[email protected] ~]# cat /etc/keepalived/keepalived.conf  
! Configuration File for keepalived
 
global_defs {
   notification_email {
     [email protected]
     [email protected]
     [email protected]
   }
   notification_email_from
      [email protected]
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}
 
vrrp_instance VI_1 {
    state BACKUP   ##node01和node02都配置成BACKUP,角色由优先级确定
    interface eth2
    virtual_router_id 71
    priority 100      ##node01的优先级设置比node02的高
    advert_int 1
    nopreempt        ##设置不抢占(需在BACKUP状态下设置才有效)
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.10.70
    }
}
 
virtual_server
192.168.10.70 3306 {
    delay_loop 6
    lb_algo wrr
    lb_kind DR
    nat_mask 255.255.255.0
    persistence_timeout 50
    protocol TCP
 
    real_server 192.168.10.71 3306 {
        weight 100
        notify_down /etc/keepalived/stopkeepalived.sh #3306端口不可用则执行脚本
        TCP_CHECK {
        connect_timeout 10
        nb_get_retry 3
        delay_before_retry 3
        connect_port 3306           
 
        }
    }
}


4、编辑node02的keepalived的配置文件

[[email protected] ~]# cat /etc/keepalived/keepalived.conf  
! Configuration File for keepalived
 
global_defs {
   notification_email {
     [email protected]
     [email protected]
     [email protected]
   }
   notification_email_from
      [email protected]
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}
 
vrrp_instance VI_1 {
    state BACKUP       ##node01和node02都配置成BACKUP,角色由优先级确定
    interface eth3
    virtual_router_id 71
    priority 90        ##node02的优先级设置比node01的低
    advert_int 1
    nopreempt          ##设置不抢占(需在BACKUP状态下设置才有效)
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.10.70
    }
}
 
virtual_server
192.168.10.70 3306 {
    delay_loop 6
    lb_algo wrr
    lb_kind DR
    nat_mask 255.255.255.0
    persistence_timeout 50
    protocol TCP
 
    real_server 192.168.10.72 3306 {
        weight 100
        notify_down /etc/keepalived/stopkeepalived.sh #3306端口不可用则执行脚本
        TCP_CHECK {
        connect_timeout 10
        nb_get_retry 3
        delay_before_retry 3
        connect_port 3306           
 
        }
    }
}
 
[[email protected] ~]#

5、node01和node02都编辑一个keepalived的自杀脚本/etc/keepalived/stopalived.sh,一旦检测到Mysql的3306端口不通,便执行此脚本触发vip的切换,脚本内容很简单,就是service keepalived stop就行,因为keepalived服务停止便会触发高可用的切换动作。


6、启动keepalived服务

[[email protected] ~]# service keepalived start

Starting keepalived:                                       [  OK  ]

[[email protected] ~]# service keepalived start

Starting keepalived:                                       [  OK  ]


7、观察node01的message日志,由于node01的优先级高,因此进入了master角色,vip也已经加上了

[[email protected]~]# tail -f /var/log/messages
Oct 30 22:47:46
node01 Keepalived[3170]: Starting Keepalived v1.2.7 (09/26,2012)
Oct 30 22:47:46
node01 Keepalived[3171]: Starting Healthcheck child process, pid=3173
Oct 30 22:47:46
node01 Keepalived[3171]: Starting VRRP child process, pid=3174
Oct 30 22:47:46
node01 Keepalived_vrrp[3174]: Interface queue is empty
Oct 30 22:47:46
node01 Keepalived_vrrp[3174]: Netlink reflector reports IP 192.168.10.71 added
Oct 30 22:47:46 
node01 Keepalived_vrrp[3174]: Netlink reflector reports IP
fe80::20c:29ff:fe20:a6c8 added
Oct 30 22:47:46
node01 Keepalived_vrrp[3174]: Registering Kernel netlink reflector
Oct 30 22:47:46
node01 Keepalived_vrrp[3174]: Registering Kernel netlink command channel
Oct 30 22:47:46
node01 Keepalived_vrrp[3174]: Registering gratuitous ARP shared channel
Oct 30 22:47:46
node01 kernel: IPVS: Registered protocols (TCP, UDP, SCTP, AH, ESP)
Oct 30 22:47:46
node01 kernel: IPVS: Connection hash table configured (size=4096,memory=64Kbytes)
Oct 30 22:47:46
node01 kernel: IPVS: ipvs loaded.
Oct 30 22:47:46
node01 Keepalived_vrrp[3174]: Opening file ‘/etc/keepalived/keepalived.conf‘.
Oct 30 22:47:46
node01 Keepalived_vrrp[3174]: Configuration is using : 63319 Bytes
Oct 30 22:47:46
node01 Keepalived_vrrp[3174]: Using LinkWatch kernel netlink reflector...
Oct 30 22:47:46
node01 Keepalived_healthcheckers[3173]: Interface queue is empty
Oct 30 22:47:46
node01 Keepalived_healthcheckers[3173]: Netlink reflector reports IP
192.168.10.71 added
Oct 30 22:47:46
node01 Keepalived_healthcheckers[3173]: Netlink reflector reports IP
fe80::20c:29ff:fe20:a6c8 added
Oct 30 22:47:46
node01 Keepalived_healthcheckers[3173]: Registering Kernel netlink reflector
Oct 30 22:47:46
node01 Keepalived_healthcheckers[3173]: Registering Kernel netlink command channel
Oct 30 22:47:46
node01 Keepalived_healthcheckers[3173]: Opening file ‘/etc/keepalived/keepalived.conf‘
Oct 30 22:47:46
node01 Keepalived_healthcheckers[3173]: Configuration is using : 11970 Bytes
Oct 30 22:47:46
node01 Keepalived_vrrp[3174]: VRRP sockpool: [ifindex(2), proto(112), fd(11,12)]
Oct 30 22:47:46
node01 Keepalived_healthcheckers[3173]: Using LinkWatch kernel netlink reflector...
Oct 30 22:47:46
node01 Keepalived_healthcheckers[3173]: Activating healthchecker for service
[192.168.10.71]:3306
Oct 30 22:47:46
node01 kernel: IPVS: [wrr] scheduler registered.
Oct 30 22:47:47
node01 Keepalived_vrrp[3174]: VRRP_Instance(VI_1) Transition to MASTER STATE
Oct 30 22:47:48
node01 Keepalived_vrrp[3174]: VRRP_Instance(VI_1) Entering MASTER STATE
Oct 30 22:47:48
node01 Keepalived_vrrp[3174]: VRRP_Instance(VI_1) setting protocol VIPs.
Oct 30 22:47:48
node01 Keepalived_vrrp[3174]: VRRP_Instance(VI_1) Sending gratuitous ARPs on
eth2 for 192.168.10.70
Oct 30 22:47:48
node01 Keepalived_healthcheckers[3173]: Netlink reflector reports IP
192.168.10.70 added

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8、观察node02的message日志,node02进入了BACKUP角色,VIP自然不会加上。

[[email protected] ~]# tail -f /var/log/messages
Oct 30 22:48:54
node02 Keepalived[16633]: Starting Keepalived v1.2.7 (09/26,2012)
Oct 30 22:48:54
node02 Keepalived[16634]: Starting Healthcheck child process, pid=16636
Oct 30 22:48:54
node02 Keepalived[16634]: Starting VRRP child process, pid=16637
Oct 30 22:48:54
node02 Keepalived_vrrp[16637]: Interface queue is empty
Oct 30 22:48:54
node02 Keepalived_healthcheckers[16636]: Interface queue is empty
Oct 30 22:48:54
node02 Keepalived_vrrp[16637]: Netlink reflector reports IP 192.168.10.72 added
Oct 30 22:48:54
node02 Keepalived_vrrp[16637]: Netlink reflector reports IP
fe80::250:56ff:fe34:ca7 added
Oct 30 22:48:54
node02 Keepalived_vrrp[16637]: Registering Kernel netlink reflector
Oct 30 22:48:54
node02 Keepalived_vrrp[16637]: Registering Kernel netlink command channel
Oct 30 22:48:54
node02 Keepalived_vrrp[16637]: Registering gratuitous ARP shared channel
Oct 30 22:48:54
node02 Keepalived_vrrp[16637]: Opening file ‘/etc/keepalived/keepalived.conf‘.
Oct 30 22:48:54
node02 Keepalived_healthcheckers[16636]: Netlink reflector reports IP
192.168.10.72 added
Oct 30 22:48:54
node02 Keepalived_healthcheckers[16636]: Netlink reflector reports IP
fe80::250:56ff:fe34:ca7 added
Oct 30 22:48:54
node02 Keepalived_healthcheckers[16636]: Registering Kernel netlink reflector
Oct 30 22:48:54
node02 Keepalived_healthcheckers[16636]: Registering Kernel netlink command channel
Oct 30 22:48:54
node02 Keepalived_healthcheckers[16636]: Opening file‘/etc/keepalived/keepalived.conf‘.
Oct 30 22:48:54
node02 Keepalived_healthcheckers[16636]: Configuration is using : 11988 Bytes
Oct 30 22:48:54
node02 Keepalived_vrrp[16637]: Configuration is using : 63337 Bytes
Oct 30 22:48:54
node02 Keepalived_vrrp[16637]: Using LinkWatch kernel netlink reflector...
Oct 30 22:48:54
node02 Keepalived_vrrp[16637]: VRRP_Instance(VI_1) Entering BACKUP STATE
Oct 30 22:48:54
node02 Keepalived_healthcheckers[16636]: Using LinkWatch kernel netlink reflector...
Oct 30 22:48:54
node02 Keepalived_vrrp[16637]: VRRP sockpool: [ifindex(2), proto(112),fd(10,11)]
Oct 30 22:48:54
node02 Keepalived_healthcheckers[16636]: Activating healthchecker for
service [192.168.10.72]:3306

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9、测试vip是否可能用来登录mysql,由于此时vip在node01上,我们就在node02上使用vip来测试登录,可见是没有问题的

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五、Mysql高可用测试

1、停止node01的mysql服务,3306端口自然不通,keepalived检测到3306端口不通后执行自杀脚本停止自身服务,VIP被移除释放出来

[[email protected] ~]# service mysql stop
Shutting down MySQL..                                     [  OK  ]

2、观察node01的messages日志可以明显看出整个过程,VIP也已经不见了

[[email protected] ~]# tail -f /var/log/messages
Oct 30 23:06:42
node01 Keepalived_healthcheckers[3173]: TCP connection to [192.168.10.71]:3306 failed !!!
Oct 30 23:06:42
node01 Keepalived_healthcheckers[3173]: Removing service [192.168.10.71]:3306
from VS [192.168.10.70]:3306
Oct 30 23:06:42
node01 Keepalived_healthcheckers[3173]: Executing [/etc/keepalived/stopkeepalived.sh]
for service [192.168.10.71]:3306 in VS [192.168.10.70]:3306
Oct 30 23:06:42
node01 Keepalived_healthcheckers[3173]: Lost quorum 1-0=1 > 0 for VS [192.168.10.70]:3306
Oct 30 23:06:42
node01 Keepalived_healthcheckers[3173]: SMTP connection ERROR to [192.168.200.1]:25.
Oct 30 23:06:42
node01 kernel: IPVS: __ip_vs_del_service: enter
Oct 30 23:06:42
node01 Keepalived[3171]: Stopping Keepalived v1.2.7 (09/26,2012)
Oct 30 23:06:42
node01 Keepalived_vrrp[3174]: VRRP_Instance(VI_1) sending 0 priority
Oct 30 23:06:42
node01 Keepalived_vrrp[3174]: VRRP_Instance(VI_1) removing protocol VIPs.

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3、观察node02的messages日志,可以看到node02进入了MASTER角色,接管了VIP,VIP已经加上,从日志的时间看,切换的过程不过花了1秒,可说是秒级切换了。

[[email protected] ~]# tail -f /var/log/messages
Oct 30 23:06:42
node02 Keepalived_vrrp[16637]: VRRP_Instance(VI_1) Transition to MASTER STATE
Oct 30 23:06:43
node02 Keepalived_vrrp[16637]: VRRP_Instance(VI_1) Entering MASTER STATE
Oct 30 23:06:43
node02 Keepalived_vrrp[16637]: VRRP_Instance(VI_1) setting protocol VIPs.
Oct 30 23:06:43
node02 Keepalived_vrrp[16637]: VRRP_Instance(VI_1) Sending gratuitous ARPs
on eth3 for 192.168.10.70
Oct 30 23:06:43
node02 Keepalived_healthcheckers[16636]: Netlink reflector reports IP 192.168.10.70 added

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由于node01的keepalived进程被自杀脚本停止了,因此需要手动启动。之前我想是否需要跑一个监控脚本把keepalived服务自动开起来呢,后来我觉得不必要,因为如果mysql的服务依然异常,就算keepalived的服务起来了,它检测到本机的3306端口不通,还是会再次自杀。而既然mysql服务已经异常、端口都不通了,一般也是需要手动检查干预把mysql启动起来的,因此在mysql服务正常后再顺便手动起一下keepalived就好了。

本文出自 “江健龙的技术博客” 博客,请务必保留此出处http://jiangjianlong.blog.51cto.com/3735273/1981994

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