Greetings. I'm using monit to check a device on my local lan to ensure
it's responsive. This is what I was previously using:
check host resolver2 address 192.168.1.13
every 5 cycles
if failed ping4
then exec /usr/local/bin/pushover
repeat every 2 cycles
At random in the middle of the night, I'd occasionally get an alert that
ping failed. Device was up and responsive. Modified it to:
check host resolver2 address 192.168.1.13
every 5 cycles
if failed ping4 count 5 timeout 5 seconds
then exec /usr/local/bin/pushover
repeat every 2 cycles
Which seemed to work for a while, but the failures returned. So modified
it to this:
check host resolver2 address 192.168.1.13
every 5 cycles
if failed ping4 count 5 responsetime 200 milliseconds timeout 10 seconds
then exec /usr/local/bin/pushover
repeat every 2 cycles
However, this causes an immediate failure with 'Speed failed'. I increased
responsetime to 1 second, same. Increased to 10 seconds, same. The
specific error logged is
Nov 5 09:52:45 ntpviz monit[676]: 'resolver2' response time 6.173 ms
doesn't match limit [time = 10 s]
I may be misunderstanding the difference - or the interaction - between
responsetime and timeout. The device is just a raspberry pi zero, with a
typical responsetime under 10ms, and never under appreciable load.
The manual states
The RESPONSETIME parameter sets the response time limit
Is that the response time limit for any given ping, or if for example I
use a count of five, is it the time limit for all five attempts
accumulated? Even if it were the latter, since the device is reachable in
under 10ms, a count of five - assuming 1 second between each ping sent (is
that a correct assumption, or are they sent without pause?) - would still
complete in well under 10 seconds.
For reference, here's the results of a 60 second ping from the monit
server to the device:
root@ntpVIZ: /etc/monit/conf.d # ping -c 60 192.168.1.13
PING 192.168.1.13 (192.168.1.13) 56(84) bytes of data.
[elided]
--- 192.168.1.13 ping statistics ---
60 packets transmitted, 60 received, 0% packet loss, time 59094ms
rtt min/avg/max/mdev = 2.342/6.376/13.879/2.335 ms
Thanks for any insight.
--
Paul Theodoropoulos
www.anastrophe.com
