Re: recognising dead instances
Re: recognising dead instances
- Subject: Re: recognising dead instances
- From: Pascal Robert <email@hidden>
- Date: Mon, 25 Jan 2010 15:31:03 -0500
Le 10-01-25 à 15:12, Chuck Hill a écrit :
On Jan 25, 2010, at 5:35 AM, Pascal Robert wrote:
Le 10-01-25 à 01:40, Lachlan Deck a écrit :
Hi all,
just polling for ideas / techniques people use in detecting dead
instances. Naturally when there's lots of instances running in
deployment it can be hard to know if a particular instance has
locked up for some reason (and this can sometimes have a flow on
affect with the adaptor).
We use Nagios with the check_http module (bundled with the default
Nagios plugins). We check a DirectAction that simply returns "OK"
and nothing else, but we will add two more checks : one that will
fetch a very small dataset with EOF and another one by raw JDBC. By
doing one check by EOF and one by JDBC, we can see if it's a EOF
deadlock or not. The most important thing: don't check a page that
use sessions! If you try to stop an app cleanly but Nagios or other
tools keeps creating new sessions, you might have a fun time.
As for checking specific instances, you can specific the instance
number in the URL, but the problem is that the HTTP adaptor will
send you to another instance if the checked instance is dead. BUT
you can use Wonder's variant of JavaMonitor to check if a specific
instance is up or not.
Or, more easily, have the instance number returned in the response
(e.g. "4 OK") so that the script can verify that the result is from
the correct instance.
Like the patch in WONDER-450 JIRA ?
Chuck
Nagios is my friend! We are currently checking 211 services with it
(disk space, Oracle listener port, all apps, load, ntp, etc.).
----
Pascal Robert
email@hidden
AIM: MacTICanada
Twitter : MacTICanada
LinkedIn : http://www.linkedin.com/in/macti
--
Chuck Hill Senior Consultant / VP Development
Practical WebObjects - for developers who want to increase their
overall knowledge of WebObjects or who are trying to solve specific
problems.
http://www.global-village.net/products/practical_webobjects
----
Pascal Robert
email@hidden
AIM: MacTICanada
Twitter : MacTICanada
LinkedIn : http://www.linkedin.com/in/macti
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