Keepalived : Monitor with script2024/07/23 |
It's possible to monitor processes or services and other state of programs with script by Keepalived. This example is based on the environment like follows. VIP:10.0.0.30 +----------------------+ | +----------------------+ | [node01.srv.world] |10.0.0.51 | 10.0.0.52| [node02.srv.world] | | Keepalived#1 +----------+----------+ Keepalived#2 | | | | | +----------------------+ +----------------------+ |
[1] | |
[2] | For example, in addition to basic Keepalived settings, add settings to monitor HAProxy service and HTTP port. |
root@node01:~#
vi /etc/keepalived/keepalived.conf global_defs { router_id node01 notification_email { root@localhost } notification_email_from root@node01.srv.world smtp_server localhost smtp_connect_timeout 30 # add enable_script_security # specify a user who runs script # for security reasons, it should not use root script_user root } # add monitoring setting for haproxy service # possible to set any commands or your original scripts for [script] argument vrrp_script track_haproxy { script "systemctl is-active haproxy" # interval to run the script above (sec) interval 5 # if script returns non-zero 4 times, enter FAULT state fall 4 # if script returns zero 2 times, exit FAULT state rise 2 } # add monitoring setting for HTTP port vrrp_script track_http_port { script "nc -zv localhost 80" interval 5 fall 4 rise 2 } vrrp_instance VRRP1 { state MASTER # nopreempt interface enp1s0 virtual_router_id 101 priority 200 advert_int 1 virtual_ipaddress { 10.0.0.30/24 } # add track_script { track_haproxy track_http_port } smtp_alert }root@node01:~# systemctl restart keepalived
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[3] | That's OK. Verify failover and failback when HAProxy would be down. |
# primary node root@node01:~# ip address show enp1s0 2: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 52:54:00:1e:27:13 brd ff:ff:ff:ff:ff:ff inet 10.0.0.51/24 brd 10.0.0.255 scope global enp1s0 valid_lft forever preferred_lft forever inet 10.0.0.30/24 scope global secondary enp1s0 valid_lft forever preferred_lft forever inet6 fe80::5054:ff:fe1e:2713/64 scope link valid_lft forever preferred_lft foreverroot@node01:~# systemctl stop haproxy root@node01:~# systemctl is-active haproxy inactive root@node01:~# echo $? 3 root@node01:~# nc -zv localhost 80 nc: connect to localhost (127.0.0.1) port 80 (tcp) failed: Connection refused root@node01:~# echo $? 1 root@node01:~# ip address show enp1s0 2: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 52:54:00:1e:27:13 brd ff:ff:ff:ff:ff:ff inet 10.0.0.51/24 brd 10.0.0.255 scope global enp1s0 valid_lft forever preferred_lft forever inet6 fe80::5054:ff:fe1e:2713/64 scope link valid_lft forever preferred_lft foreverroot@node01:~# ssh ubuntu@node02 "ip address show enp1s0" ubuntu@node02's password: 2: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 52:54:00:4c:63:11 brd ff:ff:ff:ff:ff:ff inet 10.0.0.52/24 brd 10.0.0.255 scope global enp1s0 valid_lft forever preferred_lft forever inet 10.0.0.30/24 scope global secondary enp1s0 valid_lft forever preferred_lft forever inet6 fe80::5054:ff:fe4c:6311/64 scope link valid_lft forever preferred_lft forever |
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