[Linux-cluster] Monitoring services/customize failure criteria

[Gerhardus.Geldenhuis at gta-travel.com]

Thanks for the excellent response, I have just a few follow up
questions.

> -----Original Message-----
> From: linux-cluster-bounces at redhat.com 
> [mailto:linux-cluster-bounces at redhat.com] On Behalf Of Jeff Stoner
> Sent: 10 September 2008 18:58
> To: linux clustering
> Subject: RE: [Linux-cluster] Monitoring services/customize 
> failure criteria
> 
> 
> The Script resource is a generic resource (as opposed to the 
> more specific mysql, nfs, ip, file system, etc. resources.) 
> The script identified in the <script> section is responsible 
> for properly starting, stopping and verifying the resource is 
> functioning properly. The script needs to conform to LSB + 
> OCF RA API draft specifications. This means a script *must* 
> accept as parameters, at a minimum for use with cluster 
> services, start, stop and status. These script must exit with 
> 0 for success and a non-zero value for any non-success 
> condition (error, warning, got up on the wrong side of the 
> bed, whatever.)
> 
> > however I am not sure if it would do this for all scripts
> 
> Yes, it will.
> 
> 
> > How can I customize "failure criteria" for a cluster resource?
> 
> If you are using a Script resource, the script will get 
> called with a 'status' parameter. It is totally up to you how 
> you validate the resource. Using Apache as an example, you 
> can check for a pid file, check that at least one httpd 
> process shows up in the process list, open a socket 
> connection to the proper port to make sure it's listening, 
> send a complete HTTP request to httpd and parse the output - 
> the possibilities are many. It's your decision how you want 
> to do the validation.

Just for clarification, if I use a script resource will the same script
be used with a status parameter to check the status of the resource?

Where is the frequency specified for health checking of the resource
whether it be a custom script of apache? If we want to check health
every second where can I set this frequency? I have used luci web
interface up until now to do my configs with and have not seen anywhere
yet where I can set frequency of health checks.

I kind of expected a more complex frame work for health checking but
from my understanding of your reply it seems very simple by just
requiring the starting script to respond to status requests.

There is a script in /usr/share/cluster/script.sh which looks like it
contains some of my answers but I am not sure where this would be used.

Regards

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