Christian’s blog

Well, I just noticed a really weird thing, when you have command line arguments enabled.

Here’s a snippet from my nrpe.cfg:

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dont_blame_nrpe=1
command[check_disk]=/usr/lib/nagios/plugins/check_disk -E -w $ARG1$ -c $ARG2$ -p $ARG3$

Now, if you’d check the free space for the root, it ain’t gonna show any inode percentage (that one isn’t what I’m talking about). But if you have to use bind mounts like I do (Tivoli needs a separate “domain” — that is a separate mount point for each domain), you might wanna check the free space on the *real* device, rather than the free space on the bind mount (which is gonna show you the free space of the parent file system - in my case the root fs).

Let’s take a look at what I’m talking about. If you use the check_disk locally like this:

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# ./check_disk -w 20% -c 10% -p /apache/
DISK OK - free space: /apache 11090 MB (36% inode=36%);| /apache=19629MB;24575;27647;0;30719

Means, everything is okay, you have to pass the extra trailing slash to the –partition argument, as otherwise it would pick up the bind mount at /backup.

Now, if we do the above by means of NRPE, that’s gonna get you a different result. As I showed above, I have the check_disk command in my nrpe.cfg, I also specifically enabled command arguments during compile time.

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# ./check_nrpe -H nagios.home.barfoo.org -c check_disk -a 20% 5% /apache/
DISK CRITICAL: /apache/ not found

Now, why the hell isn’t it picking up the *original* mount point of the file system ? Guess why … Because I added -E to the command, because it didn’t use the original mount point but rather the bind mount in /backup. Removing the -E and it picks up the *original* mount point without any trouble *shrug*.

Life Nagios, NRPE