5.27.0 fails on FreeBSD 11.4

[Remko Catersels]

Monit 5.27.0 appears to have introduced a problem on FreeBSD 11.4:

# monit stop apache
/usr/local/etc/monitrc:135: The CPU I/O wait usage statistics is not available on this system
 '60'

The ‘offending’ bit of monitrc (I changed the hostname to *.example.com):

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  check system webserver.example.com
    if loadavg (1min) > 15 for 3 cycles then alert
    if loadavg (5min) > 12 for 3 cycles then alert
    if memory usage > 90% then alert
    if cpu usage (user) > 80% then alert
    if cpu usage (system) > 60% then alert
    if cpu usage (wait) > 50% then alert

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The changelog indicates lot of changes regarding CPU statistics so I suspect a bug was introduced. If I revert back to 5.26.0 it works as expected.

[Remko Catersels]

I was unable to select 2.27.0 for the version in the ticket.

[Tildeslash]

The FreeBSD doesn’t support CPU I/O wait statistics. It never did, just monit <= 5.26.0 cpu wait test was NOOP and no warning was reported on monit start.

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Monit 5.27.0 will warn if your monit configuration contains tests that are not supported on given platform.

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You can find a table with per-platform statistics overview in Monit manual: https://mmonit.com/monit/documentation/monit.html#System-resource-tests

[Tildeslash]

not bug

[Remko Catersels]

It does support the CPU statistics and load averages. It used to support those just fine. Look at the configuration snippet, I’m not looking at CPU I/O wait statistics.

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[Tildeslash]

The warning is about the following line in your configuration:

if cpu usage (wait) > 50% then alert

This line had no effect on FreeBSD even for monit <= 5.26.0 as there is no way how you can get the CPU I/O wait statistics from FreeBSD kernel.

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The only thing that Monit 5.27.0 added is a warning to let the user know that this particular monit statement has no effect on given platform (FreeBSD in this case).

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[Remko Catersels]

Oh, duh. Completely overlooked that one. In my defense the indicated line number in the warning pointed to the cpu usage (user) line.