(示例)
一:nginx + keepalived 实现HA 主从模式
二:keepalived +haproxy双机高可用方案
vi /etc/keepalived/keepalived.conf
编辑文件(主):
[javascript] view plain copy
- global_defs {
- router_id nginx_master
- }
- #监控服务.NGINX mysql等
- vrrp_script chk_nginx {
- script "/usr/local/nginx/check_nginx.sh"
- interval 2
- weight 2
- }
- vrrp_instance VI_1 {
- state MASTER
- interface eth0
- virtual_router_id 51
- priority 101
- advert_int 1
- authentication {
- auth_type PASS
- auth_pass 1111
- }
- virtual_ipaddress {
- 192.168.1.254
- }
- track_script {
- chk_nginx #检测脚本 上面配置的
- }
- }
-
global_defs {
-
router_id nginx_master
-
}
-
#监控服务.NGINX mysql等
-
vrrp_script chk_nginx {
-
script "/usr/local/nginx/check_nginx.sh"
-
interval 2
-
weight 2
-
}
-
vrrp_instance VI_1 {
-
state MASTER
-
interface eth0
-
virtual_router_id 51
-
priority 101
-
advert_int 1
-
authentication {
-
auth_type PASS
-
auth_pass 1111
-
}
-
virtual_ipaddress {
-
192.168.1.254
-
}
-
track_script {
-
chk_nginx #检测脚本 上面配置的
-
}
-
}
vi /etc/keepalived/keepalived.conf
编辑文件(从):
[javascript] view plain copy
- global_defs {
- router_id nginx_backup
- }
- #监控服务.NGINX mysql等
- vrrp_script chk_nginx {
- script "/usr/local/nginx/check_nginx.sh"
- interval 2
- weight 2
- }
- vrrp_instance VI_1 {
- state BACKUP
- interface eth0
- virtual_router_id 51
- priority 99
- advert_int 1
- authentication {
- auth_type PASS
- auth_pass 1111
- }
- virtual_ipaddress {
- 192.168.1.254
- }
- track_script {
- chk_nginx #检测脚本 上面配置的
- }
- }
-
global_defs {
-
router_id nginx_backup
-
}
-
#监控服务.NGINX mysql等
-
vrrp_script chk_nginx {
-
script "/usr/local/nginx/check_nginx.sh"
-
interval 2
-
weight 2
-
}
-
vrrp_instance VI_1 {
-
state BACKUP
-
interface eth0
-
virtual_router_id 51
-
priority 99
-
advert_int 1
-
authentication {
-
auth_type PASS
-
auth_pass 1111
-
}
-
virtual_ipaddress {
-
192.168.1.254
-
}
-
track_script {
-
chk_nginx #检测脚本 上面配置的
-
}
-
}
脚本/usr/local/nginx/check_nginx.sh"内容:
[javascript] view plain copy
- #!/bin/bash
- if [ "$(ps -ef | grep "nginx: master process"| grep -v grep )" == "" ]
- then
- /usr/local/nginx/sbin/nginx
- sleep 5
- if [ "$(ps -ef | grep "nginx: master process"| grep -v grep )" == "" ]
- then
- killall keepalived
- fi
- fi
-
#!/bin/bash
-
if [ "$(ps -ef | grep "nginx: master process"| grep -v grep )" == "" ]
-
then
-
/usr/local/nginx/sbin/nginx
-
sleep 5
-
if [ "$(ps -ef | grep "nginx: master process"| grep -v grep )" == "" ]
-
then
-
killall keepalived
-
fi
-
fi
启动并测试:
1.启动两台机器上的nginx
2.启动两台机器上的keepalived
此时使用命令 ip addr 查看虚拟IP绑定 可以看到主 有,从没有,将主机的keepalived关掉,可以看到vip绑定到了从的上面
使用其他机器访问使用wget进行访问:vip:xx/wget ?userid=20003829
查看是否能够访问,然后让本机的nginx关掉,继续使用wget看是否能够访问,如果能够访问则HA配置成功。
http://www.linuxidc.com/Linux/2012-08/69383.htm
http://www.68idc.cn/help/buildlang/ask/20150616370229.html
三、安装和设置keepalived
1、安装keepalived
> yum install keepalived
> chkconfig --add keepalived
> chkconfig --level 35 keepalived on
2、修改配置文件
配置keepalived
/etc/keepalived/keepalived.conf
内容:
=====================================================================
! Configuration File for keepalived
# 全局配置,demo中配置了邮件信息,此处因为调试中,暂时没有添加
global_defs {
}
# 集群资源监控,组合track_script进行
vrrp_script check_haproxy {
script "killall -0 haproxy"
interval 2
}
vrrp_instance HAPROXY_HA {
# 设置当前主机为主节点,如果是备用节点,则设置为BACKUP
# 备用节点时,设置为:
# state BACKUP
state MASTER
# 指定HA监测网络接口,可以用ifconfig查看来决定设置哪一个
interface eth1
# 虚拟路由标识,同一个VRRP实例要使用同一个标识,主备机
virtual_router_id 80
# 因为当前环境中VRRP组播有问题,改为使用单播发送VRRP报文
# 这个地方需要关注,之前未做此设置,结果主备节点互相不能发现,因此主备节点都升级成了MASTER,并且绑定了VIP
# 备用节点时,内容为:
# unicast_src_ip 192.168.200.199
# unicast_peer {
# 192.168.200.200
# }
unicast_src_ip 192.168.200.200
unicast_peer {
192.168.200.199
}
# 设置优先级,确保主节点的优先级高过备用节点
# 备用节点时,设置为:
# priority 80
priority 100
# 用于设定主备节点间同步检查时间间隔
advert_int 2
# 设置高可用集群中不抢占功能,在主机down后,从机接管,当主机重新恢复后,设置此功能,备机将继续提供服务,从而避免因切换导致的隐患
nopreempt
# 设置主备节点间的通信验证类型及密码,同一个VRRP实例中需一致
authentication {
auth_type PASS
auth_pass 1234
}
# 当keepalived切换状态到MASTER时,执行脚本
notify_master "/etc/keepalived/master.sh"
# 当keepalived切换状态到BACKUP时,执行脚本
notify_backup "/etc/keepalived/backup.sh"
# 当keepalived切换状态到FAULT时,执行脚本
notify_fault "/etc/keepalived/fault.sh"
# 当keepalived切换状态到STOP时,执行脚本
notify_fault "/etc/keepalived/stop.sh"
# 集群资源监控,组合vrrp_script进行
track_script {
check_haproxy
}
# 设置虚拟IP地址,当keepalived状态切换为MASTER时,此IP会自动添加到系统中
# 当状态切换到BACKUP时,此IP会自动从系统中删除
# 可以通过命令ip add查看切换后的状态
virtual_ipaddress {
192.168.200.240/24 dev eth1
}
}
====================================================================
3、启动服务
因为是为了实现haproxy的高可用,启动时需要顺序启动:
(1) 启动haproxy:
> haproxy -f /etc/haproxy/haproxy.cfg
(2) 启动keeepalived:先启动master节点,后启动BACKUP节点
> /etc/init.d/keepalived start
4、停止keeepalived服务
> /etc/init.d/keepalived stop
5、检查keeepalived的运行日志,默认keepalived的日志位于/var/log/message
> tail -n100 /var/log/message
二:Keepalived + haproxy双机高可用方案
上一篇文章已经讲到了keepalived实现双机热备,且遗留了一个问题
master的网络不通的时候,可以立即切换到slave,但是如果只是master上的应用出现问题的时候,是不会
主动切换的。
上篇文章地址:Keepalived 实现双机热备(一)
那么这篇文章主要讨论解决这个问题
我的方案是:
写一个脚本,用于监控haproxy,当然,keepalive支持脚本扩展
当master haproxy出现问题时,重启haproxy,如果重启不成功,则停掉master上面的keepalived
也可以不重启haproxy,直接停掉keepalived,让backup服务器接管master
这样haproxy出现故障,网站依然可用
系统分布如下:
ha主机 192.168.1.227:80
ha备机 192.168.1.246
keepalived 主机 192.168.1.227
keepalived备机 192.168.1.246
web1 http://192.168.1.226:8081/login
web2 http://192.168.1.246:8888/login
虚拟ip 192.168.1.99
keepalive master 和 backup 配置
vi /etc/keepalived/keepalived.conf
增加红色部分
! Configuration File for keepalived
#定义检查脚本
vrrp_script check_haproxy {
script "/etc/keepalived/check_haproxy.sh"
interval 2
weight 2
}
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
interface eth0
virtual_router_id 51
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.1.99
}
#执行检查脚本
track_script {
check_haproxy
}
}
编辑检查haproxy脚本
/etc/keepalived/check_haproxy.sh
#!/bin/bash
A=`ps -C haproxy --no-header |wc -l`
if [ $A -eq 0 ];then
/etc/init.d/keepalived stop
fi
增加执行权限,注意别忘记了
chmod 777 check_haproxy.sh
重启keepalived即可