keepalived vrrp_script,track_script作用

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 "

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

! 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" }