VMware unlimited guests DRS rules

[D8TA]

We currently have around 15 ESX hosts with numerous Windows and Linux servers as guests. For our Linux servers, since we have a limited amount of servers running, it wasn't cost effective to purchase subscriptions for all 15 hosts. So, we are thinking about setting up DRS rules so the Linux guests will only run on 2 ESX hosts. This will provide balancing for our web servers since we'll also have another DRS rule to prevent webserver1 and webserver 2 from running on the same host. Regarding licensing we have 2 subscriptions to run unlimited guests on 2 hosts. I have heard from others that DRS rules may not be the way to go and that I should also put something else in place in the event I have a guest run onto another host that is not in the DRS rules. I am not sure if anyone is monitoring their guests to ensure these VMs are running on the specific hosts they are allowed to and if so how are you doing it and do you mind sharing your technique? I wasn't sure if I could use a PowerShell script setup to run on the hour, that might be too much, to make sure all Linux servers are running on ESX host1 and host2. If not then migrate them over to host1 or host2.

We use Nagios but I am not sure how I could setup a Nagios check so if any Linux guest were running on ESX hosts other than host1 or host2 send out a notification.

Any insight or suggestions are welcomed.

[LucianoPatrão]

Hi,

We have a similar situation where all Linux should run only in 2/3 ESXi hosts.

This can be done 2 ways.

Manual:

Create DRS Rules and Groups. That VMs should run in particular hosts and those VMs(linux VMs) to a particular group and then add them to the hosts(with Host Groups). Set this to automatic and then all VMs will run in those VMs.

Problem? If you have 1000/2000 VMs is not very easy to add them manualy to Groups and to the hosts.

Automatic:

Create a Powershell script, that recognize VMs OS(so all Readhat etc.) will be automatic added to the groups that you should create and then run the DRS again.

Hope this can help.

[Miquel_A]

Hi,

Best way is to created affinity rules like you mention, one to keep them separated and one to run on a certain amount of hosts. There are some ways to automate it through PowerCli, it should be no problem. If you set up DRS affinity rules where you configure a server to "Must be " in a host/s, it won't vmotion or move to another Host, problem can happen if there are not available resources for a vm to boot/reboot on those hosts then the VM wont start. Another thing is if you set up the rule as " VM should run in this host ", then the VM will try as first choice to run on the configured hosts but if needed will run as well into different hosts.

Sorry dont know about nagios checks but I think with affinity rules you can work it out fine

Hope this helps!