Several users of the Nagios plugin check_esxi_hardware.py have contacted me to tell me that the plugin seems broken after having installed ESXi 5.0 U1.
The plugin now takes several minutes to finish the check. In the verbose mode every CIM query (for each class) takes 5 seconds before returning the results.
After a couple of checks (thanks Pascal Saul) this 'slow bug' seems to come from the U1 update and is not related to the plugin.
This can easily be verified by using your own vSphere client. Open the Hardware Status tab of the affected ESXi server then click on 'Update' and you will see that it takes a very long time (~3min) until the hardware information is collected.
Update March 27th 2012 (1):
VMware has acknowledged the bug and forwarded the case to their engineers/developers.
Update March 27th 2012 (2):
The VMware devs already responded and they're working on a bugfix. But the fix will most likely not be finished/available until Q3 2012. Thanks again to Pascal for the updates.
Update March 29th 2012:
The bug can be tracked with the following ID: PR 855196
Update April 4th 2012:
The bugfix will be released in ESXi 5 Patch 3, which is unfortunately still only scheduled for Q3.
Update May 2nd 2012:
VMware released a new Knowledge Base (KB 2016538) entry where this bug is described.
Update July 17th 2012: VMware has fixed the bug. More information.