Shulou(Shulou.com)06/01 Report--

A script that can be defined in a keepalived.conf file to implement a detection function

Example: check whether the down file exists in the / etc/keepalived directory. If so, the priority is reduced by 20. If it does not exist, it is normal.

Vrrp_script chk {

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

Interval 1

Weight-20

Note: the purpose of this script is to maintain MASTER and take MASTER offline manually.

How do I call the script defined above?

Add track_script to the vrrp instance (vrrp_instance VI_1) to trace the script

Track_script {

Chk

}

The usage of notify:

Notify_master: when the current node becomes master, the script is notified to perform the task (usually used to start a service, such as nginx,haproxy, etc.)

Notify_backup: when the current node becomes backup, notify the script to perform the task (usually used to shut down a service, such as nginx,haproxy, etc.)

Notify_fault: tasks performed when the current node fails

Example: start haproxy when it becomes master, and close haproxy when it becomes backup

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

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

A complete example:

MASTER: initial priority is 100

BACKUP: initial priority is 90

Simulate the failure caused by MASTER:

When a down file is detected in the / etc/keepalived directory, the priority decreases by 20 to 80; the priority that is lower than the BACKUP

At this point, MASTER becomes BACKUP, and the script file for notify_backup is executed (close haproxy)

At the same time, BACKUP becomes MASTER and executes the script file of notify_master (start haproxy)

Simulate MASTER failure recovery:

When the down file in the / etc/keepalived directory is deleted, the priority of the original MASTER is changed to 100, which is higher than the priority of the original BACKUP

At this time, the original MASTER is preempted by BACKUP into MASTER, and the script file of notify_master is executed at the same time (start haproxy)

At the same time, the original BACKUP is changed from MASTER to BACKUP, and the script file of notify_backup is executed at the same time (close haproxy)

Configuration of MASTER:

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 eth2 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"

Configuration of BACKUP:

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"}

The content of the script for start_haproxy.sh:

#! / bin/bashcase "$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 detects nginx, automatically degrades when the nginx service is abnormal, and automatically upgrades when nginx is restored:

Check_nginx.sh script

#! / bin/bashnmap localhost-p 80 | grep "80/tcp open" if [$?-ne 0]; then exit 10fi

Notify.sh script:

#! / bin/bashVIP=$2sendmail () {subject= "${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 configuration

! Configuration File for keepalivedglobal_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 {172.16.8.19amp 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 configuration:

Backup does not need to detect whether nginx is normal. By default, nginx is not started. Nginx is started when upgrading to MASTER, and closed when downgraded to BACKUP.

! Configuration File for keepalivedglobal_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 {172.16.8.19amp 25} notify_master "/ etc/keepalived/notify.sh master 172.16.8.19" notify_backup "/ etc/keepalived/notify.sh backup 172.16.8.19"}

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