MAX_PLUGIN_OUTPUT_LENGHT

[Matthias Flacke]

Hi,

Martin Pozdílek wrote:
> I have played with nagios whole weekend and I have several points for
> discussion.
> 
> 1) MAX_PLUGIN_OUTPUT_LENGTH and multiple line output features work well
> only for local scripts called directly by Nagios.
> 
> 2) External command file doesn't support multiple line output (nagios
> read only first line). The message length is limited too. I increased
> MAX_INPUT_BUFFER
> and MAX_PLUGIN_OUTPUT_LENGTH to 8192, but maximum length of message put
> to Nagios through external command file is still limited to 4KB. I don't
> know why. It seems, that should be expand another constant.
> 
> 3) Almost all services in my configuration are checked remotly. I can
> use NSCA or NRPE for remote monitoring servers.  The problem is, that
> NSCA and NRPE don't support
> multipline output (not so important for me) as well as messages longer
> that 1024 bytes. The syntax of send_nsca is not compatible with
> multiline support.

I cannot confirm for NRPE. NRPE is supporting multiline plugin output since 
May 8th this year.

Anyway: for NRPE there is still a hard limit caused by the architecture of the 
NRPE daemon itself. It uses a parent-child-communication via pipe. In my tests 
on Linux 2.6 I was not able to transfer more than one time PIPE_BUF (~4K). 
Seems that the pipe communication is blocking somehow after one transfer...

> I know I can increase some constants in NSCA and NRPE source codes and
> compile them on linux. But how I can do this on windows, aix ..? 
> There are many precompiled plugins and deamons without source codes on
> NagiosExchange. So I cannot modify the lenght of message for them.
> 
> The result is: If  I want to checked some services remotely, I have to
> reconcile with 1024 bytes long output on one line.
> 
> 4) I believe that point 2 is not so difficult to correct. May be it's
> already done in CSV.
> 
> The long term problem is point 3. I suggest to incorporate length of
> buffer to configuration file of NSCA, NRPE clients and servers.
> As well as you can specify port number, you could specify maximum 
> length of message.
> I know it's long time change requiered different way of allocation
> memory ... , but it will fully enabled nagios's new feature - multiple
> line output of "large" size.
> 
> Or anyone can suggest better solution. But I think today's situation
> should be solved in future.

Full ACK. We're using SSH instead in the meantime but this cannot be a long 
term solution. I'm sure that multiline and big buffer transports will raise 
with Nagios 3 getting final. For my opinion there should be no limitation 
other than specified in the MAX_* constants.

-Matthias

-- 
http://my-plugin.de/check_multi

-------------------------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc.
Still grepping through log files to find problems?  Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >> http://get.splunk.com/