Monday, May 16, 2016

Debian Jessie Keepalived simple Redis Cluster

Even though keepalived under Debian Jessi give samples of check local service with killall in /usr/share/doc/keepalived/samples/keepalived.conf.vrrp.localcheck

vrrp_script chk_haproxy {
script "killall -0 haproxy" # cheaper than pidof
interval 2 # check every 2 seconds

But Jessie only have SystemD. [killall] has been remove with SystemV.
You can still use killall5 which is the SystemV killall command.

But killall5 simulates the killall command of SysV UNIX; it sends the given signal to all processes owned by the calling UID. When does it root, it can do very bad things. BE VERY CAREFUL with the killall command on!

# cat /etc/keepalived/keepalived.conf

vrrp_script chk_redis {
script "pidof redis-server" # pidof inside of killall, just to be safe.
interval 2 # check every 2 seconds
weight 2 # add 2 points of prio if OK

vrrp_instance VI_1 {
interface eth0
state MASTER
virtual_router_id 59
priority 100 # 101 on master, 100 on backup
virtual_ipaddress {
track_script {

In my opinion pidof is safer than killall or killall5.

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