[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Some feature notes for monit, volume III

From: Martin Pala
Subject: Re: Some feature notes for monit, volume III
Date: Wed, 14 Jul 2004 23:12:48 +0200
User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7) Gecko/20040707 Debian/1.7-5

Vlada Macek wrote:

### Monit monitoring

Is there some way to detect that monit is successfully running? I
would like to ensure (from the cron) that the monit process does
not merely exist, but actually does the checks it should. That way
I would have a protection of cron-monit pair in both directions
(checking the cron's log timestamp from monit).

This catch 22 situation has been discussed before and I think that
the conclusion was to run monit from init (/etc/inittab). See also
the FAQ for rationale. A corollary was recently discussed on this
list, i.e. that monit may and should start rc-scripts. Although this
should work without to much problem now, it would help to have a way
to specify the start order of daemons. We will add this to monit..

Although monit may be run from init (I'm aware of this) and such process
starting is usually seen as assured, there is unfortunatelly a several
reasons why certainly started monit could fail to continuously monitor
the system. For example there can be bug in monit which can be triggered
by some system state, and AFAIK init will finally give up respawning a
process. I'm to spend hours and hours configuring monitoring of my
servers and it would be really sad realizing after the crash that monit
was unable to inform me because it was dead...

From my point of view, it's always good to be able to monitor a hearbeat
of something that awakens only when there are problems. Touching the
file every cycle is IMHO a good and cheap probe at the active tail of
monit. But I know there are only a few other admins so fearful as I am,
so I'm not proding this idea further, just want to explain why I wrote
this. There are certainly other (more complex) ways to solve my concern. :-)

... when you run monit on more nodes, you can cross-check monit from remote hosts too (via their monit agent)

### Service textual comments

The monit web or e-mail output may sometimes be (temporarily) read
by nontechnical people. Attaching a comment to each service
explaining what is this item or exactly what to do in case of the
failure may be handy. What about something like this:

check file ... "/proc/mdstat" desc "Disk array check. In case of
any failure, please contact any admin ASAP! Telephone..."

You may specify a special mail format per service and I think this
should cover this request?

Of course. :-) I forgot to add <description> tag to the output format
mock-ups below. It would IMHO fit to the reported structure, especially
in case monit will be someday able to put the information-rich
XML/TEXT/HTML output into the e-mail alerts. But this feature is just a
"nice addon", of course. The unexperienced human reader should be
competent and educated at least to know what to do if he/she sees red color.

I think the per-service mail format should be sufficient as describe Jan-Henrik:

 alert address@hidden with mail-format {
      from: address@hidden
   subject: $SERVICE $EVENT at $DATE
   message: Monit $ACTION $SERVICE at $DATE on $HOST.
            Yours sincerely,
            Impact - disk array check. In case of any failure,
            please contact any admin ASAP! Telephone...


reply via email to

[Prev in Thread] Current Thread [Next in Thread]