When you add a Hyper-V hosts to VMM, you must specify
either a Run As Account (stored credentials in VMM) or manually enter the
credentials. The Run As Account or the user you specify should be a local
administrator on the host. If a Run As Account is provided, then it will be
used while adding the host as well as for providing future access to the
host during its lifetime. If credentials are entered manually, then they
will only be used while adding the host. Once the host has been successfully
added, the VMM service account will be added as local administrator on the host
and used to provide any future access to it.
In other words, the VMM service account will end up in
the group for local administrator on each host.
However, I often see customers who have deployed their
own VMM server and added hosts manually with their own Domain Admin
credentials. This is just fine for a demo or a lab, but should not be done in
any production environment.
If this user is disabled, changes password or anything
else, this will indeed break the communication between VMM and the (previously)
managed hosts.
You may have noticed that once you have added your hosts –
and also created a cluster, the Run As Account located on “Host Access” tab of
the host properties are greyed out. This can’t be changed in the GUI and some
people are doing drastically things like removing the cluster – and adding it
back to VMM again with the correct Run As Account. However, if you are creating
logical switches on the hosts in the right way, through VMM, you must re-deploy
the switch configuration again afterwards. No good.
Lucky for us all, the solution is located in the API,
using Powershell.
Here are some simple lines for you to change a Run As
Account for a managed Hyper-V cluster in VMM (if the hosts are not clustered,
you are able to change the Run As Account through the GUI)
$YourClusterName = Get-SCVMHostCluster -Name "YourClusterName"
$YourRunAsAccount = Get-SCRunAsAccount -Name "YourRunAsAccount"
Set-SCVmHostCluster -VMHostCluster $YourClusterName -VMHostManagementCredential $YourRunAsAccount
