High Availability with Hyper-V (formerly Viridian)

Notes: Hans Vredevoort (30-01-2008)
These are my notes on the Hyper-V webcast by Microsoft

Building a highly available Virtual Machine with Failover Cluster Manager in Windows Server 2008 (with Hyper-V)

This two node cluster has several running VMs


Making a VM high available is simple using a Wizard



A cluster resource is created of type Virtual Machine



The Virtual Machine cluster resource is brought online on node 1




And the VM is failed over to node 2






Hyper-V on Windows Server Core

- No GUI
- Less code
- Fewer patches
- Less to service/manage
- Low surface area exposed
- More secure
- More reliable

Virtualization and High Availability go hand-in-hand

- Downtime has higher impact on hosts with many VM’s
- Schedule downtime
- Failover to another host when a servers crashes

In current version:

- 32bit/x64
- W2K3 and W2K8 supported (will be expanded)
- 4 virtual CPU’s per VM (1 in VS2005R2)
- 32GB RAM per VM (3,6GB in VS2005R2)
- 255 SCSI devices per VM (4 x 7 in VS2005R2)
- 12 Network adapters per VM (4 in VS2005R2)


Make A VM high available via Failover Cluster Manager: Configure Service or Application

It creates Virtual Machine resource

Steps:

- Install Hyper-V
- Configure Cluster (4 steps only!)
- Make VM highly available
- Failover to another machine



High Availability is included in Enterprise/DataCenter Server



No more single-subnet limitation

- No VLANs required
- Communicate across routers
- Configurable Heartbeat Timeouts


When VMM update for Hyper-V: at release

USB Storage devices for VM’s are supported

Any device is supported as long as Windows Server 2008 has a driver

Q&A


Vraag: Can you highlight Live Migration and date when it's going to launch. Also comparison between Live migration and Quick Migration

Antwoord: Windows Server 2008 will provide Quick Migration of VM's across hosts. Mike will discuss what this means in just a few slides.

Vraag: When is the Virtual Center Management for the Hyper-V expected to be released?

Antwoord: We will address this at the open Q&A at the end

Vraag: can we use Quick Migration without Hyper-V support? Especially because Hyper-V won't be included into recent RTM

Antwoord: Quick Migration is available today with Virtual Server 2005 R2

Vraag: Are there any plans to integrate .NET into Server Core thus enabling PowerShell?

Antwoord: PowerShell is not supported on Win2008. It is under investigation for a future release

Vraag: Can you remote desktop to a core server?

Antwoord: Yes, but of course there is no GUI with Core. So you get a command prompt when you connect

Vraag: During quick migration there is a loss of connectivity to the server during the move correct? So since it isn't "Live" all clients communicating with the server and have sessions active will lose their session and have to reestablish their sessions correct?

Antwoord: At the end of the day the experience to clients with Quick vs. Live migration is similiar, the biggest difference is the mechanism by which the VM state is moved from one host to another. Whether it is saved to a file and moved to another server, or copied over the network

Vraag: Do all the servers in the cluster need to be the same? Hardware and software?

Antwoord: With Windows Server 2008 the support model for qualifying clusters is new and more flexible. The one requirement with Hyper-V is that you need to have the same processor architecture across the nodes in the cluster

Vraag: Save state question: What is the possibility that we will encounter application or services that get corrupt because of save state incompatibility? I think this is dependent on the application, services, or resource being able to support VSS, true?

Antwoord: Save state is independent of VSS and backup mechanisms, there is no requirement that apps have VSS Writers. So there is no compatibility risks

Vraag: since quick migration fails over the lun, what happens if i have more than one VM on the same shared lun and only one VM fails?

Antwoord: Within a Cluster a "Group" is the smallest unit of failover. VM cluster resources and the disks they are dependent on are in the same "Group" and failover as a unit. If you wanted to have multiple VM's on a common LUN, then they would be in the same group and failover as a unit

Vraag: How does the storage transition work with quick migration? In a SAN, do all Hyper-V hosts access all LUNs or does the SAN LUN access need to be remapped during the migration to allow the target Hyper-V host access?

Antwoord: Management of the LUN's is handled by Clustering, leveraging tried and true mechanisms that have been deployed for File, Print, SQL, and Exchange for years. All nodes see all LUN's and Clustering Service handles managing the LUN's and ensuring only 1 node ever has access to a disk to ensure volumes are not corrupted

Vraag: But if I save the state of a machine isn't that about the same as shutting the machine down for 5-15 seconds (hibernate) and then bringing it back online? won't that incur some session time outs?

Antwoord: Mike's slide with timing is complete failover times. That's the time to save the state, move the disk, and restore the state.

Vraag: Per earlier answer, when did Powershell get pulled from Windows Server 2008?

Antwoord: PowerShell is included in Windows Server 2008. The question was in regards to Server Core which is a special SKU of Windows which is a minimal stripped down version of Windows. Core does not include PowerShell

Vraag: So basically you need to configure one VM per Lun? What happens if i have 100s of VMs i want to protect with quick migration? I need to also manage 100 luns?

Antwoord: You can configure your LUN's in multiple ways. Either multiple VM's on a single LUN or 1 LUN per VM

Vraag: I configure a 50GB iSCSI LUN on my host. I created a VM on that LUN. Then I made it an HA VM. I think this makes that whole 50GB LUN a clustered resource rather than just the VM files/folders. Due to this, I'm unable to create another HA VM on that same LUN even though I have 40GB available. Is that by design? If so, what is a best practice?

Antwoord: You can place multiple VM's on a single LUN

Vraag: Can I access from a VM, my SAN over the FC interface?

Antwoord: With iSCSI using the Microsoft iSCSI Software Initiator you can access external SAN disks locally

Vraag: Is there still the need for a shared quorum disk in Server 2008?

Antwoord: There is a WebCast tomorrow on Quorum Considerations with Win2008. The short answer is that it's configurable, you can use many mechanisms to determine majority and quorum for the cluster. The Witness Disk (previously called the Quorum Disk) is still there

Vraag: Are there any issues with using the Hyper-V Manager MMC on a remote machine if the Hyper-V hosts are running Server Core, assuming remote management of Server Core has been enabled?

Antwoord: With Server Core you can remotely manage them with GUI tools. So yes, you can definitely do that. Like configuring clusters from the command line can be challenging, but you can install the Remote Server Admin Tools on your Vista client and run the nice snap-in with it's wizards against a Core server

Vraag: Reference the early reply - "You can place multiple VM's on a single LUN". Is this possible after I have made the LUN a cluster resource already?

Antwoord: Yes you can add multiple VM's on a single LUN

Vraag: If I have a fault-tolerant DHCP service, Is there any downside to using reserved DHCP addresses for my Hyper-V cluster as opposed to static IP addresses?

Antwoord: It's just like another server, the same considerations apply

Vraag: Will Hyper-V support XP and Vista OS's? In the beta and RC builds it only supported Win 2003 and Win 2008 OS's?

Antwoord: This is a good discussion point, I'll have Mike cover this in the Q&A session at the end

Vraag: Can you build a Windows Server 2008 Cluster solely by using Hyper-V,i.e. can the cluster nodes be VMs? What about the shared storage in that case?

Antwoord: That is what we refer to as a "Guest Cluster", where the VM's are actually nodes in a cluster and applications failover from one VM to another. Yes, that is fully supported

Vraag: How fast have you been able to failover VMs in testing, in a standard 2K3 cluster I have been able to do it in less than 90 seconds?

Antwoord: Refer to Mike's slide that shows Quick Migration testing and benchmarking we've done. It depends on memory size and disk I/O bandwidth

Vraag: what is the price of 2008 datacenter

Antwoord: $2,999 per processor

Vraag: Will Microsoft provide an iSCSI target solution outside of Windows Storage Server?

Antwoord: For Windows Server 2008 the iSCSI Software Target will only be included int he Storage Server SKU

Vraag: Will Microsoft server 2008 hyper-v be available with guests vms on top of the host OS "and" another option with the hypervisor layer with child partitions on top of the hypervisor layer next to the parent partion host OS? Is this choice available or will it only come out in the parent child partition model?

Antwoord: Yes, you could combine Guest and Host clustering. This would enable health monitoring of applications within guests

Vraag: Does NLB work well with a stretch cluster?

Antwoord: NLB cannot be stretched across subnets

Vraag: I think Mike mentioned it, but I missed it. Is there any P2V functionality built in?

Antwoord: Migration of VM's from Physical to Virtual will be included with System Center Virtual Machine Manager

Vraag: Will quick migration be integrated into System Center Virtual Machine Manager?

Antwoord: Yes, the next version of VMM will be completely integrated with clustering and quick migration

Vraag: Did mike just say that the current beta release of hyper-v will be the same version in the RTM?

Antwoord: Answered verbally. Thanks for your question!

Vraag: Is Hyper-V included with WS08 FIBS? FIBS = For Itanium Based Systems

Antwoord: x64 Only

Vraag: How does quick migration compare to Vmware's vMotion?

Antwoord: Answered verbally. Thanks for your question!

Vraag: Why is IIS not clusterable in a W2K8? In our environment IIS is just another service running in the cluster, so NLB is overkill and not an option for us.

Antwoord: Please contact your Microsoft rep and raise this as a feature that is important to you. This feedback is important to understanding scenarios important to customers

Vraag: What types of external devices will not be supported in Hyper-V?

Antwoord: Mike addressed this in Q&A

Vraag: Do you mean that in first Hyper-V version Live Migration won't be included?

Antwoord: Windows Server 2008 will include Quick Migration

Vraag: Is there really a practical reason to use virtual multiple processors? Isn't Hyper-V able to "balance" the cpu usage across the host's actual CPUs?

Antwoord: Mike will address this in Q&A

Vraag: Do all of the systems in the cluster need to be identical

Antwoord: No, it just needs to pass the Cluster Validate tool. For Hyper-V all the nodes need to have the same processor architecture

Vraag: Can a VM be placed on a SAN raw disk (not a VHD)?

Antwoord: Yes, these are referred to as Pass Through disks

Vraag: Can you cluster a 2008 non-Hyper VM Physical machine with a 2008 HyperV Virtual machine over long distances?

Antwoord: Yes

Vraag: Other than heartbeats, to mitigate split brain, are there any other components that make up the arbitration process of the cluster? For example, a witness or a remote CIFS share?

Antwoord: Yes, there are many mechanisms and we have an entire WebCast on this tomorrow. Cluster health monitoring is extensive

Vraag: Can VHD's be dynamically expanded (offline/online)?

Antwoord: Yes you can. VM must be offline

Vraag: Is Hyper-V running in production anywhere at this time ?

Antwoord: Yes

Vraag: Can you set up the failover nodes as offline nodes until failover? (to avoid extra licensing costs--cold failover)

Antwoord: Yes you can configure cluster nodes this way, but it does not relieve you of licensing

Vraag: Will the feature set change between current beta and RTM?

Antwoord: Answered verbally. Thanks for your question!

Vraag: Any specific recommendations for possible virtualization of SQL 2008/ SQL 2005?

Antwoord: Answered verbally. Thanks for your question!

Vraag: Can you post a link to tomorrow's webcast?

Antwoord: http://forums.microsoft.com/TechNet/ShowPost.aspx?PostID=2698876&SiteID=17

Vraag: What's the reasoning behind publishing a separate Windows Server 2008 SKU without Hyper-V?

Antwoord: Mike will address this in the Q&A

Vraag: Will there be anything in the memory handling that resembles VMWares balloon driver?

Antwoord: Not at this time, we are evaluating this for a future release

Vraag: Where I can find head to head comparison to VmWare Esx (Performance, etc)

Antwoord: Answered verbally. Thanks for your question!

Vraag: What exactly is the Microsoft Hyper-V server SKU?

Antwoord: http://www.microsoft.com/windowsserver2008/editions/overview.mspx

Vraag: follow-up to the running nodes as offline question--why wouldn't it resolve the duplicate licensing issue? Part of the Software Assurance benefit is the ability to run a cold-failover instance without purchasing a second license.

Antwoord: Please contact your Microsoft rep for licensing questions

Vraag: Can you give an example of enlightened functionality in Hyper-V. Is this the same as paravirtualization?

Antwoord: A software setup of Integration Services is performed on a VM. This makes a Windows Server 2008 VM aware of it being a VM. It adds to the performance and yes, this is called paravirtualization.

Vraag: Does the Vm´s still need to have VMadditions installed? (With Hyper-V)

Antwoord: They are called Hyper-V integration Services.