keepalived vrrp_script,track_scr

作者: SkTj | 来源:发表于2019-03-01 10:32 被阅读9次

keepalived vrrp_script,track_scr
keepalived之vrrp_script详解
keepalived中的vrrp_script模块
centos下keepalived使用问题记录
在5.6上部署keepalived
keepalived离线安装
Keepalived实践
集群介绍、keepalived介绍、用keepalived配置高
Keepalived基本讲解
keepalived 实现高可用

可以在keepalived.conf文件中定义的脚本，用以实现某个检测功能；

例：检测/etc/keepalived目录下down文件是否存在，如果存在则优先级减20，如果不存在表示正常

vrrp_script chk {

script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"

interval 1

weight -20

注：这个脚本的作用是用于维护MASTER,使MASTER手动下线

如何调用上面定义的脚本呢？

在vrrp实例中(vrrp_instance VI_1)加上track_script用于追踪脚本

track_script {

chk

}

notify的用法：

notify_master:当当前节点成为master时，通知脚本执行任务(一般用于启动某服务，比如nginx,haproxy等)

notify_backup:当当前节点成为backup时，通知脚本执行任务(一般用于关闭某服务，比如nginx,haproxy等)

notify_fault：当当前节点出现故障，执行的任务;

例：当成为master时启动haproxy,当成为backup时关闭haproxy

notify_master "/etc/keepalived/start_haproxy.sh start"

notify_backup "/etc/keepalived/start_haproxy.sh stop"

一个完整的实例：

MASTER:初始priority为100

BACKUP:初始priority为90

模拟MASTER产生故障：

当检测到/etc/keepalived目录下有down文件时，priority减少20，变为80；低于BACKUP的priority；

此时MASTER变成BACKUP，同时执行notify_backup的脚本文件（关闭haproxy）；

同时BACKUP变成MASTER，同时执行notify_master的脚本文件（启动haproxy）；

模拟MASTER故障恢复：

当删除/etc/keepalived目录下的down文件时，原MASTER的优先级又变为100，高于原BACKUP的priority;

此时原MASTER由BACKUP又抢占成了MASTER,同时执行notify_master的脚本文件（启动haproxy）；

同时原BACKUP由MASTER又变了BACKUP,同时执行notify_backup的脚本文件（关闭haproxy）；

MASTER的配置：

global_defs {
notification_email {
acassen@firewall.loc
failover@firewall.loc
sysadmin@firewall.loc
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 192.168.200.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk {
script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
interval 1
weight -20
}
vrrp_instance VI_1 {
state MASTER
interface eth1
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.22.245
}
track_script {
chk
}
notify_master "/etc/keepalived/start_haproxy.sh start"
notify_backup "/etc/keepalived/start_haproxy.sh stop"
BACKUP的配置：

global_defs {
notification_email {
acassen@firewall.loc
failover@firewall.loc
sysadmin@firewall.loc
}
notification_email_from Alexandre.Cassen@firewall.loc
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 90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.22.245
}
notify_master "/etc/keepalived/start_haproxy.sh start"
notify_backup "/etc/keepalived/start_haproxy.sh stop"

}
start_haproxy.sh的脚本内容：

!/bin/bash

case " $1" in start) /etc/init.d/haproxy start ;; stop) /etc/init.d/haproxy stop ;; restart) /etc/init.d/haproxy stop /etc/init.d/haproxy start *) echo "Usage:$ 0 start|stop|restart"
;;
esac
keepalived检测nginx,当nginx服务不正常时自动降级，当nginx恢复时自动升级：

check_nginx.sh脚本

!/bin/bash

nmap localhost -p 80 | grep "80/tcp open"
if [ $? -ne 0 ];then
exit 10
fi
notify.sh脚本：

!/bin/bash

VIP= $2 sendmail (){ subject="$ {VIP}'s server keepalived state is translate"
content="date +'%F %T': hostname's state change to master"
echo $content | mail -s "$ subject" zhengwei.liu@staples.cn
}
case " $1" in master) nmap localhost -p 80 | grep "80/tcp open" if [$ ? -ne 0 ];then
/etc/init.d/nginx start
fi
sendmail
;;
backup)
nginx_psr=ps -C nginx --no-header | wc -l
if [ $nginx_psr -ne 0 ];then /etc/init.d/nginx stop fi ;; *) echo "Usage:$ 0 master|backup VIP"
;;
esac
MASTER配置

! Configuration File for keepalived

global_defs {
notification_email {
acassen@firewall.loc
failover@firewall.loc
sysadmin@firewall.loc
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 192.168.200.1
smtp_connect_timeout 30
router_id https
}
vrrp_script chk_nginx {
script "/etc/keepalived/check_nginx.sh"
interval 1
weight -20
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 54
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
172.16.8.19/25
}
track_script {
chk_nginx
}
notify_master "/etc/keepalived/notify.sh master 172.16.8.19"
notify_backup "/etc/keepalived/notify.sh backup 172.16.8.19"
}
BACKUP配置：

backup无需检测nginx是否正常，默认nginx是未启动的，当升级为MASTER时启动nginx，当降级为BACKUP时关闭

! Configuration File for keepalived

global_defs {
notification_email {
acassen@firewall.loc
failover@firewall.loc
sysadmin@firewall.loc
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 192.168.200.1
smtp_connect_timeout 30
router_id https
}

vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 54
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
172.16.8.19/25
}
notify_master "/etc/keepalived/notify.sh master 172.16.8.19"
notify_backup "/etc/keepalived/notify.sh backup 172.16.8.19"
}