Check Command: check_esxi_hardware

check_esxi_hardware queries the CIM (Common Information Model) server running on the ESXi server to retrieve the current status of all discovered hardware. This check command comes from

Frequently Asked Questions

Q: The plugin is executed fine but then it hangs on a certain CIM element on a DELL server. Verbose output:

18:21:56 Connection to \https://esxi-001

18:21:56 Check classe OMC_SMASHFirmwareIdentity

18:21:57 Element Name = System BIOS

18:21:57 VersionString = 1.3.6

18:21:57 Check classe CIM_Chassis

18:21:57 Element Name = Chassis

18:21:57 Manufacturer = Dell Inc.

18:21:57 SerialNumber = xxxxx

18:21:57 Model = PowerEdge R710

18:21:57 Element Op Status = 0

18:21:57 Check classe CIM_Card

18:21:58 Element Name = unknown

18:21:58 Element Op Status = 0

18:21:58 Check classe CIM_ComputerSystem

CRITICAL: Execution time too long!

A: According to user feedback and lots of tests, such problems are related to the Dell OMSA Offline Bundle. Especially OMSA version 6.5 made problems on ESXi 5.x servers.

Q: I get the following error message from the plugin:

(0, 'Socket error: [Errno 111] Connection refused')

A: Make sure the Monitoring Server is able to access tcp port 5989 (cim) on the ESX(i) server. Alternatively you can also set a different port with the -C parameter if you have a special DNAT or port forwarding in place.

Q: How do I use the -i parameter to ignore certain alarms?

A: As written in the documentation, the -i parameter awaits a comma separated list of elements to ignore. The "tricky" part is to find the correct element names (they can be pretty long sometimes). Run the plugin in verbose mode to have a list of all CIM elements. Here’s an example how to ignore several elements:

./ -H myesxi -U root -P mypass -V dell -i "IPMI
SEL","Power Supply 2 Status 0: Failure status","System Board 1 Riser
Config Err 0: Config Error"

Q: I have the following warning showing up but my server shows all sensors green:

WARNING : System Board 1 Riser Config Err 0: Connected - Server: Dell
Inc. PowerEdge R620 s/n: xxxxxxx System BIOS: 1.1.2 2012-03-08

A: It seems that all Dell PowerEdge x620 servers are affected, it looks like a BMC firmware bug to me. A workaround for this bugger is in place since version 20121027. Please check <a href=“/blog/299/check_esxi_hardware_dell-pe-620-workaround-riser-config-err-connected”>this post</a> for detailed information.

Q: The plugin returns the following output:

Authentication Error! - Server:

A: There are several answers to that:

  1. Make sure you are either using the ESXi root user or that you create a user which is member of the root group. See <a href=“/blog/114/check-esxi-wbem-esxi-4.1-user-authorization”>this post</a> for a short description how to do that.
  2. The password you are using has some special characters like a question mark and you need to quote them.
  3. The password you are using has a Dollar sign ($) which you need to single-quote.

Generally, always put quotes around your password as this assures the content is handled as string.

Q: Can the plugin also monitor other stuff like VMFS disk usage or cpu/memory usage?

A: No. The plugin makes use of the CIM (Common Infrastructure Model) API . The so-called CIM elements cover hardware only.

Q: Some hardware is not being monitored by the plugin.

A: The plugin can only monitor the hardware which is “shown” by the server via the CIM API. If the hardware vendor does not include a certain hardware element into the CIM elements, then this piece of hardware can not be monitored. In all the years I’ve only seen this on no-name machines (and SUN) though.

Q: The plugin is so slow that a timeout occurs.

A: In such cases always verify how the behavior is on your vSphere client in the Hardware tab. Click on the “Update” link and then “Refresh”. Are they fast or do they also take a long time to update?

In ESXi 5.0 Update 1, a bug was causing slow hardware discovery/checks. See this article for more information.

Q: The plugin suddenly times out, but it was working fine before. The plugin returns the following output:

UNKNOWN: (0, 'Socket error: [Errno 110] Connection timed out')

A: In rare cases it is possible, that the sfcbd-watchdog service, running on the ESXi server, isn’t working correctly anymore. Follow VMware KB entry 1013080 and restart the service by logging into the ESXi server by ssh and launch the following command:

/etc/init.d/sfcbd-watchdog restart

If this still doesn’t resolve your issue, a manual restart of the “CIM Server” could help. This option is found under the “Configuration” tab → “Security Profile”. Click on “Service … Properties”.

Q: After an update of the pywbem package the plugin doesnt work anymore. The following output is shown in verbose mode:

Unknown CIM Error: (0, 'SSL error: certificate verify failed')

A: This was seen in SLES 11 SP3 after an update of the package python-pywbem from 0.7-6.13 to 0.7-6.22. After reverting to the older version, the plugin worked again.

Update September 9th 2014: This error will be fixed in a future release of, but it depends on the release of the new pywbem upstream version. See


Update June 26th 2015: This issue was fixed in version 20150626.

Q: On an IBM server with the ESXi image from IBM the following error appears but works fine with the regular image vom VMware:

Traceback (most recent call last):

   File "./", line 625, in verboseoutput("Element
Name = "+elementName)

TypeError: cannot concatenate 'str' and 'NoneType' objects

A: The CIM definition coming from the IBM image seems to be lacking some information. Version 20150119 fixes this issue.

Q: I updated my Ubuntu 14.04 and pywbem package 0.7.0-4ubuntu1~14.04.1 was installed. Since then I get the following error when the plugin is run:

Traceback (most recent call last):

   File "/usr/local/bin/", line 619, in
<module>instance_list = wbemclient.EnumerateInstances(classe)

   File "/usr/lib/pymodules/python2.7/pywbem/", line 421,
in EnumerateInstances


   File "/usr/lib/pymodules/python2.7/pywbem/", line 183,
in imethodcall

no_verification = self.no_verification)

   File "/usr/lib/pymodules/python2.7/pywbem/", line 268, in


File "/usr/lib/python2.7/", line 969, in endheaders


File "/usr/lib/python2.7/", line 829, in \_send_output


File "/usr/lib/pymodules/python2.7/pywbem/", line 115, in


File "/usr/lib/pymodules/python2.7/pywbem/", line 167, in

except ( Err.SSLError, SSL.SSLError, SSL.SSLTimeoutError

AttributeError: 'module' object has no attribute 'SSLTimeoutError'

A: It seems that Ubuntu did the same as SUSE, RedHat and Centos in the past: The pywbem was patched without changing the upstream version number. This goes into the same direction as issue #7 ( A temporary fix is to manually install the older pywbem package like this:

aptitude install python-pywbem=0.7.0-4


Update June 26th 2015: This issue was fixed in version 20150626.

Q: I use python3 but the plugin throws an error:

File "./check_esxi_hardware.py3", line 440

print "%s %s" % (time.strftime("%Y%m%d %H:%M:%S"), message)
SyntaxError: invalid syntax

A: An issue was opened on github ( to address this compatibility issue.


Update: This issue was fixed in version 20181001.

Q: I sometimes get the following error on an ESXi host:

CRITICAL: (0, 'Socket error: [Errno 8] \_ssl.c:510: EOF occurred in
violation of protocol')

A: After a lot of debugging and testing with a plugin user we came to the conclusion, that this problem arises from the ESXi host, not the plugin. A tcpdump revealed, that the ESXi host sent a TCP Reset packet rather then starting to submit data. A reboot of the affected ESXi host resolved the problem.


Update October 17th, 2019: Such situations can (sometimes) also be confirmed in the vSphere Client UI using the Monitor → Hardware Health window. A click on the “REFRESH” button results in an error in the recent tasks list:

“A general system error occurred: Server closed connection after 0 response bytes read; <SSL…..

General System Error

Q: I have several ESXi hosts behind the same IP (NAT). How can I use the check_esxi_hardware?

A: Since version 20160531 it is possible to manually define the CIM port (which defaults to 5989). So if you set up port forwarding (DNAT) you can now monitor all ESXi servers behind the same NAT-address. The parameter you want in this case is ”-C“ (or –cimport).

Q: Is the plugin compatible with ESXi 6.x?

A: Yes. Please note that starting with ESXi 6.5 you might have to enable the CIM/WBEM services first, as they are disabled by default. Refer to

CIM Server Service

Q: I can’t execute the plugin and get the following error message. Permissions are correct however (e.g. 755).

execvpe(/usr/lib64/nagios/plugins/ failed:
Permission denied

A: This error comes from SELinux. You need to write an allow rule for it.

Q: The plugin reports the following problem with memory, but no memory hardware issues can be found on the server:

CRITICAL : Memory - Server: HP ProLiant DL380p Gen8 s/n....

A: It is possible that an alert needs to be cleared in the servers IPMI log first. To do that, you need to login into your ESXi server with SSH and run the following commands:

localcli hardware ipmi sel clear

/sbin/ restart

This might affect other CIM entries as well. So it’s a wise idea to clear the IPMI system event log (sel) first before investigating further.

Q: Certain hardware elements show incorrect health/operational states, e.g. “Cooling Unit 1 Fans”:

20190205 00:26:26

Element Name = Cooling Unit 1 Fans

20190205 00:26:26

Element HealthState = 1020190205 00:26:26

Global exit set to WARNING

A: Certain server models might show false hardware alarms when these particular hardware elements were disabled in BIOS, are idle or have disabled sensors. From the HP FAQ:


PR 2157501: You might see false hardware health alarms due to disabled or idle Intelligent Platform Management Interface (IPMI) sensors. Disabled IPMI sensors, or sensors that do not report any data, might generate false hardware health alarms.

In this case it makes sense to ignore these elements using the -i parameter.

Q: The check_esxi_hardware plugin is not working (anymore) since ESXi 6.7 U2/U3 on DELL servers.

A: The issue seems to be the “OpenManage” VIB. This can be verified by checking the list of installed VIB’s on an ESXi server:

esxcli software vib list

After uninstalling the OpenManage VIB, the plugin works again. According to DELL, ESXi 6.7 U2 is not yet officially supported (as of July 2019) by OpenManage:


OpenManage Integration for VMware vCenter v4.3.1 (Initial 4.3 Download) (4.3.1 Release Notes) (4.3 Manuals)Does not add official 6.7 U2 support (support for 6.7 U2 will come in the fall with the next major release)

See also official VMware KB 74696 entry for this.

Update October 15th 2019: OMSA 9.3.1 fixes this issue.