NSCA using PROCESS_FILE

[Thomas Guyot-Sionnest]

On 28/02/07 06:22 AM, Hendrik Baecker wrote:
> Gerd Mueller schrieb:
>> Hi Hendrik,
>>
>>   
>>> 1. What happens when the external Daemon crashes and the pipe will be
>>> erased? 
>>>     
>> How should the pipe be erased by accident? If you do not erease it it
>> will survive. 
>>   
> Ok, you are right. If your Daemon which creates the pipe won't clean it
> up, the pipe will resist until some higher presence came down and clean
> it up (kernel, user, whatever).
>>   
>>> Does is hurts nagios? 
>>>     
>> I see different problem. If the daemon dies the pipe would never be
>> cleaned, nagios will not be able to attach data to such a full pipe. So
>> nagios will be slowed down until the ocsp/ochp commands timeout. We had
>> this problem with the perfdata commands and our nagiosgrapher. That is
>> the only reason why we switched to use udp rather than using a pipe. But
>> summarized I do not see such a problem with using a pipe.
>>   
> There is a little difference of internal work lies on how you are
> create/connect to the pipe... blocking or non-blocking is the question.
> If blocking:
> No write access if there is no listener
> and also no listener when there is no writer.
> 
> if non-blocking:
> listener without writer is possible but
> writing without listener will fail
> but: writing to full pipe will fail with same error as writing without
> listener....

I just checked on a host I'm building and apparently Nagios doesn't
block on full pipe. So far I haven't had any dieing daemon problems either.

I also I recommend running the daemon trough daemontools, so that if it
ever die it will get restarted right away.

Thomas


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