[Pacemaker] [Linux-HA]I revised resource-agents of tomcat.

[Brett Delle Grazie]

Hi Dejan / Tomo,

Apologies for the long delay in response but I've been scratching my
head as to some of the patches
caused me some concern.

Specifically:
1) Patch #2 from the first link
(http://www.gossamer-threads.com/lists/linuxha/dev/77116)
This changes the 'status' check to a 'monitor' operation.

The monitor operation should be configured by the user to point at the
application running within tomcat, e.g. a HEAD request to a version
page or similar.

However this operation can and will frequently block for an
indeterminate period of time.

It might be worthwhile making the 'status' operation a process-id
check for _tomcat_ rather than a monitor operation which traditionally
checks the availability of the application running within tomcat.

There are distinct conditions where Tomcat may still be working but
the applications running on it are dead in the water.

This all depends upon whether there is value in distinguishing between
'tomcat is dead' and 'the app running on tomcat is dead but tomcat is
fine'.

2) The patch contained in the second link and possibly some of the
patches in the first link.
The string search is based upon the premise that every tomcat resource
agent must have a unique name.
If this name is used in the CATALINA_OPTIONS variable it will be
visible in the process table.
To be honest, I've never liked this and actually prefer the process ID check.
I believe it was originally done to support ease of resource agent
configuration as at the time, I don't think the
process ID operations using Tomcat's start/stop scripts were
particularly reliable.

Tomcat's come a long way in that time and perhaps we could use both. i.e.
If the PID is defined, use it, if its not defined, use the string search.
In either case - I think the -Dname option is to ambiguous (what
happens if the application requires a 'name' parameter to be set on
the command line?) we should probably increase this to
-Dtomcat_ra_name=<name> or something similar.

These are just observations and may no longer be correct as its been
about a year since I've used tomcat resource agent.

I'm not actively monitoring the list right now so please cc me if you
wish me to comment further.

Thanks

Kind regards,

Brett

On 23 January 2012 20:23, Dejan Muhamedagic <dejanmm at fastmail.fm> wrote:
> Hi,
>
> On Thu, Jan 19, 2012 at 02:00:31PM +0900, nozawat wrote:
>> Hi Brett
>
> Adding Brett to the list of recipients :)
>
> Cheers,
>
> Dejan
>
> P.S. Always good to just send again to the ML too.
>
>> I want comment if possible about a patch of following tomcat.
>>
>> <http://www.gossamer-threads.com/lists/linuxha/dev/77116>
>> ->I did three trifling corrections.
>>
>> <http://www.gossamer-threads.com/lists/linuxha/dev/75950#75950>
>> ->I change the check method of the process.
>>
>> Regards,
>> Tomo