Load Guest to any available host.

[Jeremy Brook]

I am new to VMWare currently migrating over from Citrix.  In Xen servers are set up as Pool Masters and Slaves.  If I start a guest machine, it auto picks a host (if now home server is specified) and loads it ok.  Is there a way to do similar in Vmware.  Currently my vms are assigned to a host, if I was to do a full shut down of the guests and hosts then decided I want to do some maintenance on one of the hosts, it seems silly then I have to  log on directly to the host (vmcenter is slower than a car with no wheels to boot) then use the create/register VMs and select individual ones, in an interface which clearly hasn't been designed by an actual users of vmware.  I just wanna see a list of VMs, and simply start them.

[Alexander Schneider]

Hi Jeremy,

I think the feature you are looking for is called DRS (or Distributed Ressource Scheduler).

If you group your hosts in a cluster, you can enable DRS at this level. And depending on the configuration of DRS it will look for the optimal host to start the VM on.

If you want to start a bunch of VMs at once, select either your Cluster, Datacenter or vCenter in the left pane, go to the "VMs" Tab in the right pane, select all the VMs you want to power on, right click >> Power >> Power On

[Jeremy Brook]

Cheers I will look into this now, I have a feeling I may not be licenced though for that feature.  The reason I said that is when was first setting vmware a couple of weeks ago, I tried to setup a cluster, it allowed me to create a cluster but I couldn't add anything to it because of a licensing error so I just dismissed it as not usable.

These are the items my licence says I can use, what would DRS fall under, do you know or is it a specific item thats not listed for my licence?

Unlimited virtual SMP

H.264 for Remote Console Connections

vCenter agent for VMware host

vSphere API

Content Library

Storage APIs

vSphere vMotion

X-Switch vMotion

vSphere HA

vSphere Data Protection

vShield Endpoint

vSphere Replication

vShield Zones

Hot-Pluggable virtual HW

vSphere Storage vMotion

Shared Smart Card Reader

vSphere FT (up to 2 virtual CPUs)

Virtual Volumes

APIs for Storage Awareness

Storage-Policy Based Management

vSphere Storage APIs for Array Integration

Remote virtual Serial Port Concentrator

vSphere Encrypted vMotion

 

[Alexander Schneider]

Yes, true, you need to be licensed with "Enterprise Plus" to be able to use DRS.

It is then listed as "vSphere DRS"

[Jeremy Brook]

When I bought vmware, there wasn't an enterprice plus option, there were only the following, of which I choice standard


Essentials Plus Kit
vSphere® Standard
vSphere® Foundation

But yeah just check foundation is what includes DRS.  I recall redding the summary

"Automated load balancing now looks at storage characteristics to determine the best place for a given virtual machine’s data when it is created and used overtime."

Which might suggest I can still do what I need to do, I guess by setting up vsphere HA

[Alexander Schneider]

Yes, you're right, Broadcom changed the licensing model.

If you want to have the "Enterprise Plus" features, you have to go with "Foundation" nowadays:

https://www.vmware.com/products/cloud-infrastructure/vsphere-foundation

[Jeremy Brook]

Weird, I can see DRS as an option in a cluster so will investigate more as it didn't moan about licences when I turned it on.  I have created the cluster but haven't added hosts yet because they have running VMs . 

Do you know, if I migrate all the running guests from one host to the other, then add that host to the cluster.  Am I able to easily migrate the guests from the the host that isn't in the cluster to the other machine that's part of the cluster than add my second host to the cluster.  Or must I shut down all guests and add both hosts to the cluster at the exact same time ?

[Alexander Schneider]

To add or remove hosts from a cluster you don't have to stop or migrate the VMs. Just drag the host in vCenter onto the cluster object.

Then, at least, with your licensing (and shared storage as a prerequisite) you can use HA and vMotion.

[Jeremy Brook]

I can't add the hosts to the cluster because the hosts enter maintenance mode

it gives the error  "Hosts will enter maintenance mode before they are moved to the cluster. You might need to either power off or migrate powered on and suspended virtual machines."

I currently use shared storage between my hosts and use vmotion without them being in a cluster, but yeah I do need to setup vsphere ha.

[Jeremy Brook]

It looks like I can't use a cluster or am I setting it up wrong but then I am confused how I can use vsphere HA.  So I have VMWare standard, which supports vSphere HA.  To use this feature it seems all your hosts need to be in the same cluster.  Fair enough. The problem though is to enable a cluster I need to setup a Distributed switch, which i just tried to do and I get the error that my Standard licence doesn't support VDS (Vsphere distributed Switch), but VDS is a prerequisite of HA, so how can I setup HA without it, it doesn't seem possible

[Alexander Schneider]

Distributed Switches are no requirement for HA.

And they also aren't a requirement for Clusters. You just need to setup Standard Switches on every host instead.

And for HA you just need to create VM Port Groups on every host with the exact same name.

[Jeremy Brook]

Cheers for all your help Alexander, I think now my cluster and HA is setup.  There was just a lot of misleading info within vcenter, and using their quickstart option was where it was pointing to setting a up a VDS before I could add hosts to the client.

Just have to test it now, going to disconnect a host from the network and see if the guest fires up on the other host. 

But once again, thanks for all your help and sorry of it seemed like I was being a noob ... which I was :D 

[Kent Wicker]

As mentioned you don't need a distributed switch, a standard switch is fine but all port groups must be named the same on the hosts in the cluster.

Can you vmotion from one host to another?  Right click, migrate, change compute.  If that is not working you need to fix that first before a cluster will work.  Your nodes you want to be in the cluster need shared storage and a vmotion vmkernel adapter on the same network for vmotion to work.  Once vmotion is working you can migrate the VM's off, put host1 in maintenance mode, and then put it in the cluster.  If you have different generations of processors, you will want to enable EVC on the cluster which masks newer features of newer processors to enable vmotion compatibility between new and old.

Also as mentioned, the standard license does not have DRS so you would need to manually vmotion to balance the load and put them where you want.  if you upgrade, DRS will do this for you and you can create rules so they are placed where you want them.

Standard does include HA so if a host dies, HA will automatically start up the VM's that were on that host on another host in the cluster.

[Jeremy Brook]

Yeah vmotion was all working fine, and I migrated many times (even in the last few weeks just for testing etc).

Tbh I have been setting up the cluster, and it looks like I can achieve what I want without using DRS using the cluster VM/Hosts Groups and Rules.  For example I have a couple of DNS/DHCP etc servers, so I have create a rule that when they start the system will always try and put them on separate hosts.  And I can also force particular VMs to only load on a particular host.  It may not be as automated/monitored as DRS but might suffice. 

[vasquezu]

The only thing i would add to your plan for using the VM/Host rules is to go for the "should run on" option instead of the "must run" when binding them to a specific host.