keeping VMs on one host

[Gonzouk]

Hello,

We have 8 hosts and for some reason our bosses bought a Windows 2012 datacentre license for 1 host as we have a project which needs to run on 12 x 2012 Windows servers.  I said that is a risk as we can't vMotion and what happens if that host crashes?

I need to highlight the issues as they don't think it is a big issue should the host crash?  Is it easy to move the servers manually as I haven't done this before, maybe I can just import the vmx file again to another host from the datastores?

Any other issues would be great to know as it will be me and a colleague picking up the issue should it happen not them.

Thanks

[Alim786]

I will assume you have HA and DRS features and enabled. This means that you can use the DRS Group Manager feature to create a Rule to keep the VMs on a particular Host but still allowing for them to be vmotioned automatically upon a Host failure.

[Gonzouk]

That is right, but I'm not a license person and they say the license is for one particular host and must stay on that, is that even possible?

[Alim786]

I understand your License restriction. However my point is that if you have no choice, then this is the best option. If the Host fails, I do not think that the bosses will be worrying about Licenses if the VMs cannot be recovered quickly. If the Host fails with these VMs on them, there is no way of knowing how much corruption they will have and if they could be restarted successfully on another Host. Even if you do this manually, you are still on an unlicensed Host. Therefore I do not understand the logic of not implementing the feature mentioned above.

[Vikas Shitole]

Hi Friend,

To enable DRS we need enterprise plus VC license. HA comes with even first level license. Both features need to be enabled from vCenter. Hence you require at-least one additional host and 1 vCenter server instance with valid/required license.

If you can not go for enterprise plus license, you could go for basic vCenter license which allows you to have 3 host in a HA cluster & configure 1 host with all VMs. at the same time, configure other host for failover.

Yes, if you can not satisfy above requirement for giving HA to your environment. You need to be ready for downtime. Once you resolve the issue on failed host, you will have ability to power it on again.

Other option is, you will have to attach shared datastore between the host that will have all the VMs and other host which you will use for powering on VMs when first host has crashed.

Message was edited by: vVision

[Gonzouk]

Hi,

Thanks all for you info, it is really appreciated.

We have 8 x hosts and have a datacentre licence on all that let's us install any OS up to 2008 R2, we have vCentre and DRS and HA are running.  Now we have a new project for 12 x Windows 2012 servers and our bosses bought a license to let us install Windows 2012 servers on one host only until they get budget to add to the rest.  They have asked us to keep them on the one server using DRS.  The Windows 2012 guests will be on shared storage (Dell Equallogic SANs) can these be easily manually moved?  Possible corruption or registration issues?

Alim made a good point that if I am told to manually move them to another host then why not have 2 hosts in the HA/DRS but keep them on one server, but I'm not sure how the licensing works if you buy it for one host, is that just 1 host out of the 8 or always the same host.  I'm not sure this can be set.

Thanks

[Alim786]

Unfortunately I am not an expert in Microsoft Server 2012 Licensing. From what I have read briefly, you can only run a 2012 Server VM on the Host that has the license - the same Host. But, you better get it confirmed by Microsoft or a Partner in writing.

However, my main point is still valid. You can still configure DRS to keep these VMs on the same, licensed Host but in a HA scenario where that Host fails, you can still recover those VMs to other Hosts in the Cluster and then worry about your licenses afterwards.

[Gonzouk]

Many thanks Alim786, do you have the link to that MS licensing you read?

Your idea makes total sense, but my bosses my see it different :smileysad:

[Alim786]

See link below :-

http://download.microsoft.com/download/4/D/B/4DB352D1-C610-466A-9AAF-EEF4F4CFFF27/WS2012_Licensing-Pricing_FAQ.pdf

Good Luck !

[Gonzouk]

Thanks, what page were you referring to?

[Vikas Shitole]

Hi Friend,

Some suggestions.

1. You need to be very clear about MS licensing. If  that license let you create 2012 windows server, then it must be applied first on that particular host.

2.  If that license is already applied on other host, my understanding is, 2012 VM from that host can not be powered on other host where this license is not there. Hence, when licensed host fails, you need to be ready for downtime. Neither DRS nor HA can help to avoid this downtime.

There are some options you can recover from this situation.

1. Bring back licensed host back and power on the VMs again.

2. Make ready other host with valid license or you can use your earlier failed host license( not sure if it works), and power on the VMs. Make sure both failed host and new host has shared datastore.

1. If you want to keep all VMs on licensed host for 2012 Vms, use DRS VM-Host affinity must rule. But in case of host failure DRS can not move these VMs , even HA can not help.

2. If you do not use this rule, DRS may not aware about MS licensing and it may try vMotion these VMs to other available host for load balancing (where valid license is not there). Eventually vMotion is going to be failed.

Overall, if you do not have valid license for one more host, downtime is must, you will have above mentioned options to recover it.

You can create one dummy VM with 2012 windows server on licensed host and try vMotion to other host where required license for 2012 windows server is not there

[Alim786]

I would just like to clarify the above post. If you did not have licenses for ALL your Hosts in the cluster, you would NOT be compliant of Microsoft Licensing. However, this does NOT mean your VMs would suffer downtime.

[Vikas Shitole]

If licensed host fails, where these VMs will be powered ON (as there is only one licensed host with 2012 windows VM can be created).

[Alim786]

I can only base my comments upon my discussions with Microsoft Licensing. The License is only a "paper issue" for compliance purposes. MS state that you must license ALL Hosts in a CLUSTER. You enter separate MAK keys when installing Server 2012 on VMs so therefore VMs will continue working regardless of which Host they are on.

[Vikas Shitole]

All right. I am not aware about MS licensing. Only I assume, if license is applied on a host and can create upto 2012 windows machine using that license on that host, same VM should not allowed on other host. If it allowed, then what is the use of license.

As per your comment, I understand license is for 2012 windows VM & is not aligned to particular host. However, earlier comments shows that 2012Vms can be created on particular host due to MS licensing. If it is not aligned with host, then that VM can be migrated to any applicable host.

Does each 2012 windows VM require separate MS license?

[Alim786]

From my discussions with Microsoft and reading their documents recently, you can have either a Standard or Datacenter License for ESXi Hosts. They will then give you MAK keys to enter for activation on VMs for the number of Licenses allowed. A Datacenter License on a Host allows for unlimited but Standard is based upon Processors. The document link I gave earlier gives you more details.

[CedricAnto]

That is right, but I'm not a license person and they say the license is for one particular host and must stay on that, is that even possible?

>>> This is possible by setting VM affinity. If there is an issue with the OS, you may be asked to prove with logging that VM did not move to a unlicensed host(vmware.log will have this history)

>>> This obviously is a trade-off made for paid HA/DRS and VMotion feature.

>>> You might need to assess the cost of licensing multiple hosts or atleast one other host in the cluster that is specified as a failover host. So incase of host failure VM will restart on a host that is still licensed (OS perspective)

I would recommend you to reach out to sales teams of the products to assist with assessment.