This is the first article in a series of vSphere Security articles that I have planned. The majority of this article is based on vSphere/ESXi 5.1, though I will include any 5.5 information that I find relevant.
I think lockdown mode is a feature that is rarely understood, and even more rarely used. Researching this article I’ve already encountered several different definitions that weren’t quite right. As far as I can see there are no differences between lockdown more in 5.5 and 5.1.
The vSphere Security guide says (emphasis mine):
To increase the security of your ESXi hosts, you can put them in lockdown mode. In lockdown mode, all
operations must be performed through vCenter Server. Only the vpxuser user has authentication
permissions, no other users can perform operations against the host directly.
In short, lockdown mode means you can ONLY manage the host via vCenter. The only exception is via the DCUI.
DataStore conflicts with an existing DataStore in the DataCenter – Manually disabling Storage I/O Control
I ran into this issue yesterday while reconnecting hosts in our vCenter Server following a complete reinstall - the reasons for which are a long story, but suffice to say that there were new certificates and the host passwords were encrypted with the old ones.
The LUNs had been unpresented at the hardware level by the storage team, but had not been unmounted or removed from vCenter. This is *not* the way to remove storage - let me re-iterate: remove storage properly. Unfortunately in this case the storage was removed badly - doing this can lead to a condition called "All Paths Down" or APD which is best explained by Cormac Hogan (@vmwarestorage) in the article Handling the All Paths Down (APD) condition.