Re: recognising dead instances
Re: recognising dead instances
- Subject: Re: recognising dead instances
- From: Lachlan Deck <email@hidden>
- Date: Tue, 26 Jan 2010 11:21:24 +1100
Thanks all. Some good ideas.
On 26/01/2010, at 7:12 AM, Chuck Hill wrote:
> 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.
>
> 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
with regards,
--
Lachlan Deck
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