Here’s one for all you VMware ESXi users out there for which I know there are quite a few of you running it in you work or home VMware labs. This issue was first brought to my attention by Stu Radnidge’s article here which also provided a link to this VMware Knowledge based article.
As outlined in the VMware KB article there are a couple of scenarios where you may experience the following error message with ESXi and vCenter Server 4.0:
“Cannot install the vCenter agent service. Unknown Installer error”
When Does It Occur?
This error occurs when:
- Adding an ESXi 4.0 host to vCenter Server 4.0 or 4.0 Update 1 and then removing then re-adding the ESXi 4.0 host back to vCenter Server 4.0 or 4.0 Update 1
- Or by upgrading vCenter Server from 4.0 to 4.0 Update 1
It should be pointed out that the error message “Cannot install the vCenter agent service. Unknown Installer error” can be caused by a handful of different issues such as this which I have experienced before though in this instance what differentiates it is when looking in the /var/log/vmware/vpx-iupgrade.log file on the ESXi 4.0 host you will see the following – of particular note is the last line which mentions ‘Out of Memory’
Acquiring lock /tmp/bootbank.lck
Copying vpxa.vgz to /bootbank/vpxa.vgz
Editing /bootbank/boot.cfg to add module vpxa.vgz
 2009-11-30 15:21:49: status = 0
 2009-11-30 15:21:49: exec /sbin/vmkramdisk vpxa.vgz
Failed to mount archive: Out of memory
The VMware KB article doesn’t go into any real detail on why this error is affecting ESXi instances only (ie: and not ESX) though Stu’s article gives valuable and interesting information as to why – well worth a read for those of you that like to know what is going on under the hood.
What Does It Cause?
If this error does occur to your ESXi host(s) and vCenter Server 4.0 instance then you can expect one or both of the following undesirable results (from the VMware KB article):
After the error, the ESXi host does not display in vCenter Server or stays disconnected.
All attempts to add or reconnect ESXi hosts to vCenter Server fail.
At this stage there isn’t any fix available though VMware Engineering are working on producing one – no ETA at the time of writing this post. Here is the latest KB update on a resolution:
VMware engineering is aware of this issue and is working on a fix. This article will be updated when this fix is available.
There are currently 3 options available to help you bring the host back in to VC Management.
- Contact VMware support and they can provide a temporary workaround to reconnect the host to vCenter. For more information on contacting VMware support, see How to Submit a Support Request.
- Wait for the official fix.
- Reboot the host, then try to add or reconnect it to vCenter Server.