Monitoring hosts behind a load balancer 🔗 link

From: user-5425c7b245e1@xymon.invalid [mailto:user-5425c7b245e1@xymon.invalid] On Behalf Of Steve Holmes
Sent: Tuesday, June 15, 2010 12:07 PM
To: user-ae9b8668bcde@xymon.invalid
Subject: [hobbit] Monitoring hosts behind a load balancer

Greetings, I'm monitoring several Solaris 10 servers which are behind an F5 load balancer. One of the features of the F5 is that it answers pings for all of the hosts behind it, even if they are all down. Has anyone devised a method of testing the servers for being alive in this context? There are no other network based tests being done. Yes, all of the other tests eventually go purple in Xymon, but we'd like to know that the hosts are down when that happens.

Thanks,
Steve Holmes
ITaP/Purdue University

Steve Holmes wrote:

Greetings, I'm monitoring several Solaris 10 servers which are behind an
F5 load balancer. One of the features of the F5 is that it answers pings
for all of the hosts behind it, even if they are all down. Has anyone
devised a method of testing the servers for being alive in this context?
There are no other network based tests being done. Yes, all of the other
tests eventually go purple in Xymon, but we'd like to know that the
hosts are down when that happens.

On Tue, Jun 15, 2010 at 12:18 PM, Ryan Novosielski <user-ae4522577e16@xymon.invalid>wrote:

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Steve Holmes wrote:

Greetings, I'm monitoring several Solaris 10 servers which are behind an
F5 load balancer. One of the features of the F5 is that it answers pings
for all of the hosts behind it, even if they are all down. Has anyone
devised a method of testing the servers for being alive in this context?
There are no other network based tests being done. Yes, all of the other
tests eventually go purple in Xymon, but we'd like to know that the
hosts are down when that happens.

Have you considered devmon which monitors the f5 itself? I'm not sure
what parameters it shows, however. I believe you can also do a content
test (eg. your f5 can be configured to say something foreboding and you
can configure Xymon to look for it as bad news).

On Tue, Jun 15, 2010 at 12:07 PM, Steve Holmes <user-ec1bf77b1b44@xymon.invalid> wrote:

Greetings, I'm monitoring several Solaris 10 servers which are behind an F5
load balancer. One of the features of the F5 is that it answers pings for
all of the hosts behind it, even if they are all down. Has anyone devised a
method of testing the servers for being alive in this context? There are no
other network based tests being done. Yes, all of the other tests eventually
go purple in Xymon, but we'd like to know that the hosts are down when that
happens.

Thanks,
Steve Holmes
ITaP/Purdue University

On Tue, Jun 15, 2010 at 12:42 PM, Ralph Mitchell <user-00a5e44c48c0@xymon.invalid>wrote:

I used to have some scripts that would make SOAP requests to an F5 to get
the pools and pool member status.  I no longer have access to that system,
but I may have a backup at home.

I based my scripts on a bunch of example programs in the F5 SDK.  IIRC, I
altered a couple of the perl scripts to output lines like:

     pool1 server1 OK
     pool1 server2 DOWN
     etc...

Then you just run around a loop reading the lines and sending BB status
messages.

As long as your F5 is checking the servers occasionally, this approach
works OK.

Ralph Mitchell


On Tue, Jun 15, 2010 at 12:07 PM, Steve Holmes <user-ec1bf77b1b44@xymon.invalid> wrote:

Greetings, I'm monitoring several Solaris 10 servers which are behind an
F5 load balancer. One of the features of the F5 is that it answers pings for
all of the hosts behind it, even if they are all down. Has anyone devised a
method of testing the servers for being alive in this context? There are no
other network based tests being done. Yes, all of the other tests eventually
go purple in Xymon, but we'd like to know that the hosts are down when that
happens.

Thanks,
Steve Holmes
ITaP/Purdue University

Steve

-- 
The test of a democracy is not the magnificence of buildings or the speed of
automobiles or the efficiency of air transportation, but rather the care
given to the welfare of all the people. -Helen Adams Keller, lecturer and
author (1880-1968)

Truth never damages a cause that is just. -Mohandas Karamchand Gandhi
(1869-1948)

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Steve Holmes wrote:

On Tue, Jun 15, 2010 at 12:42 PM, Ralph Mitchell
<user-00a5e44c48c0@xymon.invalid <mailto:user-00a5e44c48c0@xymon.invalid>> wrote:

    I used to have some scripts that would make SOAP requests to an F5
    to get the pools and pool member status.  I no longer have access to
    that system, but I may have a backup at home.

    I based my scripts on a bunch of example programs in the F5 SDK.
     IIRC, I altered a couple of the perl scripts to output lines like:

         pool1 server1 OK
         pool1 server2 DOWN
         etc...

    Then you just run around a loop reading the lines and sending BB
    status messages.

    As long as your F5 is checking the servers occasionally, this
    approach works OK.

    Ralph Mitchell


    On Tue, Jun 15, 2010 at 12:07 PM, Steve Holmes <user-ec1bf77b1b44@xymon.invalid
    <mailto:user-ec1bf77b1b44@xymon.invalid>> wrote:

        Greetings, I'm monitoring several Solaris 10 servers which are
        behind an F5 load balancer. One of the features of the F5 is
        that it answers pings for all of the hosts behind it, even if
        they are all down. Has anyone devised a method of testing the
        servers for being alive in this context? There are no other
        network based tests being done. Yes, all of the other tests
        eventually go purple in Xymon, but we'd like to know that the
        hosts are down when that happens.

        Thanks,
        Steve Holmes
        ITaP/Purdue University


Thanks! I'll check with the F5 admin to see if this might be doable.
Steve

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\__/ Univ. of Med. and Dent.|IST/CST-Academic Svcs. - ADMC 450, Newark
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On Tue, Jun 15, 2010 at 1:03 PM, Ryan Novosielski <user-ae4522577e16@xymon.invalid>wrote:

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Steve Holmes wrote:

On Tue, Jun 15, 2010 at 12:42 PM, Ralph Mitchell
<user-00a5e44c48c0@xymon.invalid <mailto:user-00a5e44c48c0@xymon.invalid>> wrote:

    I used to have some scripts that would make SOAP requests to an F5
    to get the pools and pool member status.  I no longer have access to
    that system, but I may have a backup at home.

    I based my scripts on a bunch of example programs in the F5 SDK.
     IIRC, I altered a couple of the perl scripts to output lines like:

         pool1 server1 OK
         pool1 server2 DOWN
         etc...

    Then you just run around a loop reading the lines and sending BB
    status messages.

    As long as your F5 is checking the servers occasionally, this
    approach works OK.

    Ralph Mitchell


    On Tue, Jun 15, 2010 at 12:07 PM, Steve Holmes <user-ec1bf77b1b44@xymon.invalid
    <mailto:user-ec1bf77b1b44@xymon.invalid>> wrote:

        Greetings, I'm monitoring several Solaris 10 servers which are
        behind an F5 load balancer. One of the features of the F5 is
        that it answers pings for all of the hosts behind it, even if
        they are all down. Has anyone devised a method of testing the
        servers for being alive in this context? There are no other
        network based tests being done. Yes, all of the other tests
        eventually go purple in Xymon, but we'd like to know that the
        hosts are down when that happens.

        Thanks,
        Steve Holmes
        ITaP/Purdue University


Thanks! I'll check with the F5 admin to see if this might be doable.
Steve

It would not surprise me though if this is exactly what the F5 devmon
template gives you via SNMP. Might be worth a check. If you just
download the tar and look at the templates directory under F5, you'll
the OID's file should tell you what's monitored. Hate to see duplication
of effort. :)