VMware vSphere

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  • 1.  Changing DNS

    Posted Jul 28, 2014 08:06 AM

    Hi all,

    anyone knows if there is some known impact changing DNS server in Network configuration on a single ESXi 4.00 Host?

    Can i do it without restarting it?

    Thanks to all



  • 2.  RE: Changing DNS

    Posted Jul 28, 2014 10:15 AM

    You should be able to change the DNS server settings on the fly without any issues. No reboot required.

    André



  • 3.  RE: Changing DNS

    Posted Jul 28, 2014 11:57 AM

    Thank you.

    I have changed the setting 1 hour ago more or less. Seems OK.

    regards



  • 4.  RE: Changing DNS

    Posted Jul 28, 2014 12:08 PM

    As mentioned, you shouldn't experience any issues with the change, except the DNS Server itself doesn't work properly (i.e. doesn't properly resolve queries). Anyway, with a standalone ESXi host you shouldn't even run into issues without a working DNS resolution for the ESXi host itself. The VM's have their own DNS Server settings which matter.

    André



  • 5.  RE: Changing DNS

    Posted Jul 28, 2014 02:16 PM

    just for clarification to a.p. post ...with standalone unmanaged host which is not part of any HA enabled cluster you usually do not need DNS server so you can safely change this setting without any issue.

    But for environments based on vSphere 4.x with HA enabled clusters take caution because DNS is vital for HA to function correctly. (that's not the case for HA on vSphere 5.0 and later which is no more dependent on DNS)

    For more info refer:

    VMware KB: Identifying issues with and setting up name resolution on ESX/ESXi Server

    Regards,

    P.



  • 6.  RE: Changing DNS

    Posted Jul 28, 2014 02:23 PM

    Hi,

    thanks for answer.

    The environment is a ESX. 4.0 not clustered, but inserted in a Datacenter with other ESX hosts, some of them clustered.

    Now my doubt:

    I have to change DNS on a ESXi 5.1 cluster too.

    As far as i understand from your words (that's not the case for HA on vSphere 5.0 and later which is no more dependent on DNS) this operation should have no impacts here too: do i understand well?

    regards



  • 7.  RE: Changing DNS

    Posted Jul 28, 2014 03:25 PM

    yes; you can perform this change on the fly without host reboot but if you plan to do it in production environment I would recommend for any network changes first putting host into maintenance mode or at least disable HA host monitoring feature on cluster.

    (but this is just my conservative approach ...:)

    Regards,

    P.