What happens if an ESXi host that is running the vCenter Server virtual machine experiences a power outage?

vCenter Server is running in a virtual machine that is part of a vSphere HA and DRS cluster. The vCenter Server virtual machine has been tested and can successfully migrate with vMotion between all ESXi hosts in the cluster. DRS is configured for partial automation.

What happens if an ESXi host that is running the vCenter Server virtual machine experiences a power outage?

A.
All DRS cluster operations will be unavailable until the failed ESXi host is brought back online.

B.
vCenter Server will remain offline, but all virtual machines on the remaining hosts will continue without interruption.

C.
This situation cannot occur, because vCenter Server cannot be installed on a virtual machine in a vSphere HA cluster.

D.
vSphere HA will restart the vCenter Server virtual machine on another host.

20 Comments on “What happens if an ESXi host that is running the vCenter Server virtual machine experiences a power outage?

  1. Mohsin Alvi says:

    I think the answer should be “B” as
    vCenter Server will remain offline because DRS is configured for partial automation., but all virtual machines on the remaining hosts will continue without interruption.
    Ans. D can not be correct because “DRS is configured for partial automation”

  2. Ajay says:

    B can not be the correct answer because HA is also configured, which means vCenter server will be restarted on another Host despite of configuring DRS in partial automation.

    DRS is just used for load balance while HA will actually perform failover.

    So as per my opinion correct answer should be D

  3. Dzemboc77 says:

    D would be correct, If Ha was not enabled then B would be the correct answer but since HA is turned on the server would be restarted on another esxi host regardless of drs settings.

  4. Jon says:

    +1 for D, HA is running and it is independent of DRS. vMotions have proved that the vCenter Server VM can run on any host in the cluster, so the requirements for HA to work are met. HA will make sure the VM’s are restarted, and DRS will later provide recommendations on where to move the VM’s.

  5. Mohsin Alvi says:

    B is wrong as VM can not the remain offline (must be restart to another Host) until and unless manually disable by per VM in HA settings

  6. Haruna says:

    I think answer D , because if power outage occurs, then vCenter and all VMs must be restrat opon other available ESXI host. if network connection fail occurs, then vCenter will remain offline. Therefore correct answer is D.

  7. Khan says:

    This question relates to questions 805, 1310, 1475, 258, and 335. Essentially it comes down to this:

    If HA is running (as will be mentioned in the question) the answer will always be “vSphere HA will restart the VM on another host…” Without HA in the equation of the question then it will simply be “vCenter will remain offline, but all VM’s will continue without interruption…”.

  8. Ritu Raj says:

    For sure asnswer is ‘B’.
    If Vcenter is down then how HA and DRS will work???
    HA and DRS is the feature coming after installing vcenter..
    And there won’t be any effect of the VMs which are running…

    Thanks,

    1. vee says:

      It is not B “for sure”.
      HA will work without vCenter – read about HA agent that is running on each individual host.
      There would be no much sense in “High Avilability” if vCenter was a single point of failure, wouldn’t it?
      The correct answer here is “D”

    2. Gary says:

      Vcenter is not required for HA. That means if one of the hosts fail in HA cluster then all VM’s on that host will restart on other host even when Vcenter is NOT available.

      However, without Vcenter vmotion, DRS etc. will not work. Also remember for vmotion is not used for HA. Vmotion is only when things are done in planned manner and HA is definitely not planned activity.

  9. Tony Montana says:

    I also Agree with “D” as the host is the one suffering the power outage,the mechanics behind DRS and Ha will look for a suitable host.

  10. Gary says:

    Very similar question to read carefully. Here answer is B I guess.

    vCenter Server is running in a virtual machine that is part of a vSphere DRS cluster. The vCenter Server virtual machine has been tested and can successfully migrate with vMotion between all

    ESXi hosts in the cluster. DRS is configured for partial automation.

    What happens if an ESXi 5.x host that is running the vCenter Server virtual machine experiences

    a power outage?

    A. All DRS cluster operations will be unavailable until the failed ESXi host is brought back online.

    B. vCenter Server will remain offline, but all virtual machines on the remaining hosts will continue

    without interruption.

    C. This situation cannot occur, because vCenter Server cannot be installed on a virtual machine in a vSphere DRS cluster.

    D. vSphere will restart the vCenter Server virtual machine on another host.

    1. jan says:

      It’s also D here because HA Agent’s running on ESX host itself. HA starts up vCenter after a host failure. Because vMotion works, we know that HA will be able to start vCenter on other hosts.
      vCenter is only needed to reconfigure HA Agents on ESX hosts. vCenter does calculate DRS, so DRS will not work when vCenter is down. But HA works without.


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