Handling Hyper-V. In this series of articles, learn how to manage Hyper-V, from ensuring high availability to upgrading to Windows Server 2012 R2

Transcription

1 White Paper Handling Hyper-V In this series of articles, learn how to manage Hyper-V, from ensuring high availability to upgrading to Windows Server 2012 R2

2 White Paper How to Make Hyper-V Virtual Machines Highly Available Here s how to use the Failover Cluster Manager to make virtual machines fault tolerant or to create new virtual machines. By Brien Posey

3 3 One of the biggest disadvantages to running Hyper-V on standalone virtualization host servers is that the physical server can become a single point of failure. If a Hyper-V host server were to fail, then all of the virtual machines that are running on that server will also fail. Since a single host server typically runs numerous virtual machines, the failure of a single host server can lead to a major outage. The solution to this problem is to make your virtual machines fault tolerant by clustering your Hyper-V host servers. I have written a separate column describing how you can set up failover clustering, so I am not going to be repeating that process here. Instead, I am going to focus on some aspects of failover clustering that are unique to Hyper-V. If you have ever live migrated a virtual machine then you know that in order for the live migration process to succeed there have to be similarities between the host servers. Fault tolerant virtual machines are treated as clustered roles. Host Server Requirements If you have ever live migrated a virtual machine then you know that in order for the live migration process to succeed there have to be similarities between the host servers. For example, the source and destination host must have similar processor architectures. Similarly, the destination host must have a virtual switch that has the same name as the virtual switch that the virtual machine is already using. Otherwise, the live migration process will ask you to connect the virtual machine to one of the virtual switches that exists on the destination host. These same sort of limitations also come into play when you are clustering Hyper-V servers. If you read my column on setting up failover clustering then you know that the Failover Clustering Feature requires you to run a series of validation tests when setting up a failover cluster. If Hyper-V is installed on the failover clustering nodes then the validation tests will check to make sure that the nodes are configured in such a way that virtual machines can fail over from one node to another. Perhaps the most common cause of validation test failures is a virtual switch mismatch. If a Hyper-V host contains a virtual switch then every other host in the cluster must have a virtual switch with the same name. Otherwise the validation tests will fail. Similarly, if you create a virtual SAN on a Hyper-V host then every other host in the cluster must be configured with an identical virtual SAN. Otherwise the validation tests will fail. Making Hyper-V Virtual Machines Fault Tolerant One of the common misconceptions about failover clustering is that the act of setting up a failover cluster for your Hyper-V hosts automatically makes your virtual machines fault tolerant. However, the Failover Clustering feature requires you to manually specify the virtual machines that you wish to make fault tolerant. Fault tolerant virtual machines are treated as clustered roles. To make a virtual machine fault tolerant, open the Failover Cluster Manager (by choosing the Failover Cluster Manager command from the Server Manager s Tools menu) and then expand your cluster and select the Roles container. Click on the Configure Role command, found in the Actions pane, as shown in Figure 1. How to Make Hyper-V Virtual Machines PART # WP-2021-ENG-A

4 4 Figure 1. Click on the Configure Role link. At this point, Windows will launch the High Availability Wizard. Click Next to bypass the Wizard s Welcome screen and you will be taken to the role selection screen. Select the Virtual Machine role, as shown in Figure 2. The virtual machine will be listed in the Roles container. Figure 2. Select the Virtual Machine role. Click Next and then select the Click Next and then select the virtual machines that you want to make fault tolerant, as shown in Figure 3. Click Next and you will be asked to confirm your selection. Click Next again and you will be taken to a summary screen confirming that the virtual machine has been made fault tolerant, as shown in Figure 4. Click Finish and the virtual machine will be listed in the Roles container, as shown in Figure 5, page 5. As you can see, it is relatively easy to make a virtual machine fault tolerant. However, you can also create brand new virtual machines directly through the Failover Cluster Manager. If you look at the figure above, you will notice that there is a Virtual Machines option in the Actions pane. Clicking this option allows you to create a brand new virtual machine without having to use the Hyper-V Manager. How to Make Hyper-V Virtual Machines PART # WP-2021-ENG-A

5 5 Figure 3. Select the virtual machines that you wish to make fault tolerant. It is relatively easy to make a virtual machine fault tolerant. Figure 4. You should see a confirmation that the virtual machine has been added to the cluster. Figure 5. The virtual machine should be listed in the Roles container. How to Make Hyper-V Virtual Machines PART # WP-2021-ENG-A

6 6 About the Author Brien Posey is a seven time Microsoft MVP with over two decades of IT experience. As a freelance writer, Posey has written many thousands of articles and written or contributed to several dozen books on a wide variety of IT topics. Prior to going freelance, Posey was a CIO for a national chain of hospitals and healthcare facilities. He has also served as a network administrator for some of the country s largest insurance companies and for the Department of Defense at Fort Knox. When He isn t busy writing, Brien Posey enjoys exotic travel, scuba diving, and racing his Cigarette boat. You can visit his personal Web site at: How to Make Hyper-V Virtual Machines PART # WP-2021-ENG-A

7 White Paper How To Upgrade Hyper-V to Windows Server 2012 R2 This three-step process will get your virtual machines running on Microsoft s latest Windows Server version. By Brien Posey

8 8 Although Windows Server 2012 Hyper-V introduced an overwhelming number of new features, Windows Server 2012 R2 Hyper-V introduces even more. With Windows Server 2012 R2, Microsoft did a good job of filling in some of the remaining gaps in functionality that were still present after the Windows Server 2012 release. As such, it may be in your best interest to upgrade your Hyper-V servers to Windows Server 2012 R2. Upgrading a Hyper-V server from Windows Server 2012 to Windows Server 2012 R2 is a three-step process. In this article, I want to discuss the three steps involved. It may be in your best interest to upgrade your Hyper-V servers to Windows Server 2012 R2. Step 1: Live Migration The first move in this process is obviously to plan for the upgrade. Once the planning is done however, and you are actually ready to begin the upgrade process, the first step should be to find a new home for the virtual machines that currently reside on the host that you are upgrading. You can obviously live migrate the virtual machines to another host server that is running Windows Server 2012 Hyper-V. However, a more attractive option might be to set up a temporary host server that is running Windows Server 2012 R2 and then live migrate the virtual machines to it instead. There are two reasons why this approach might be a good option. First, Microsoft allows you to make a seamless transition between Windows Server 2012 Hyper-V and Windows Server 2012 R2 Hyper-V. You can move the virtual machines to the new platform simply by live migrating them. You don t have to deal with the hassles of the import/export process as you did in the past. The second reason why this method might be attractive is because the temporary host can provide extra capacity so that your production host servers do not have to bear the burden of hosting extra VMs while you are upgrading Hyper-V. Step 2: Addressing the VMs After the virtual machines finish live migrating, there is a bit of work that will probably need to be done. In all likelihood, the virtual machines will be running an outdated version of the Hyper-V Integration Services since the virtual machines were previously running on an older version of Hyper-V. In case you are not familiar with the Integration Services, they are simply a collection of drivers that allow the virtual machines to fully interact with the server hardware. The Hyper-V Integration Services are very similar to the VMware Tools. To upgrade the Integration Services, log into the virtual machine and then choose the Insert Integration Services Setup Disk from the virtual machine s Action menu, as shown in Figure 1. Hyper-V should now perform a quick check to see if the Integration Services need to be updated. If so, you will see a message similar to the one shown in Figure 2, and you can follow the prompts to update the Integration Services. The virtual machine will need to be rebooted once the Integration Services have been updated. Just because you are updating the hypervisor and the Integration Services does not mean that you have to perform an OS upgrade on the individual virtual machines. It is worth noting however, that if you are deploying Windows Server 2012 R2 Datacenter Edition as the host OS, then the license allows you to run Windows How To Upgrade Hyper-V to Windows Server 2012 R2 PART # WP-2023-ENG-A

9 9 Microsoft allows you to make a seamless transition between Windows Server 2012 Hyper-V and Windows Server 2012 R2 Hyper-V. Server 2012 R2 on as many virtual machines as you like, so long as the virtual machines are running on the host server. Step 3: The Server Upgrade The last step in the process is to upgrade the server operating system on the Hyper-V host. This is actually a really simple process. Once all of the virtual machines have been moved off of the host server, you can perform an in place upgrade. All you have to do is to insert your Windows Server 2012 R2 installation media, run Setup and follow the prompts. After the upgrade process completes, you should reboot your server. After taking some time to make sure that everything is functioning properly, you can live migrate the virtual machines back to the host. Once all of the virtual machines have been moved off of the host server, you can perform an in place upgrade. Figure 1. Choose the Insert Integration Services Setup Disk command from the Action menu. Figure 2. You will see a message like this one if the Integration Services need to be updated. How To Upgrade Hyper-V to Windows Server 2012 R2 PART # WP-2023-ENG-A

10 10 About the Author Brien Posey is a seven time Microsoft MVP with over two decades of IT experience. As a freelance writer, Posey has written many thousands of articles and written or contributed to several dozen books on a wide variety of IT topics. Prior to going freelance, Posey was a CIO for a national chain of hospitals and healthcare facilities. He has also served as a network administrator for some of the country s largest insurance companies and for the Department of Defense at Fort Knox. When He isn t busy writing, Brien Posey enjoys exotic travel, scuba diving, and racing his Cigarette boat. You can visit his personal Web site at: How To Upgrade Hyper-V to Windows Server 2012 R2 PART # WP-2023-ENG-A

11 White Paper How To Work with Hyper-V Checkpoints Here s a quick breakdown on how to roll back to an earlier Windows Server 2012 R2 Hyper-V checkpoint. By Brien Posey

12 12 Checkpoints are a feature of Windows Server 2012 R2 Hyper-V that allow you to roll a virtual machine back to a previous state. Occasionally you may need to perform administrative actions that are potentially dangerous (such as a registry modification or an Active Directory schema extension). In these types of situations, you can give yourself a bit of a safety net by using Hyper-V checkpoints. Checkpoints are a feature of Windows Server 2012 R2 Hyper-V that allow you to roll a virtual machine back to a previous state. Creating a checkpoint is a very simple process. Before you perform the potentially dangerous administrative action, right click on the virtual machine and choose the Checkpoint command from the shortcut menu, as shown in Figure 1, page 7. Figure 1. Right click on the virtual machine and choose the Checkpoint command from the shortcut menu. When Hyper-V finishes creating the checkpoint the checkpoint will appear in the list of checkpoints beneath the virtual machine, as shown in Figure 2. Figure 2. The checkpoint has been created. How To Work with Hyper-V Checkpoints PART # WP-2022-ENG-A

13 13 Once the checkpoint has been created, you can perform whatever administrative action you needed to do. Figure 3. Right click on the Checkpoint and choose the Delete Checkpoint command from the shortcut menu. Once the checkpoint has been created, you can perform whatever administrative action you needed to do. If the administrative action is successful, you should delete the checkpoint upon completion. Checkpoints degrade read performance for the virtual machine, so you don t want to leave unnecessary checkpoints in place. You can get rid of an unwanted checkpoint by right clicking on the checkpoint and choosing the Delete Checkpoint command from the shortcut menu, as shown in Figure 3. If you have an entire series of checkpoints that you need to remove, you can save time by using the Delete Checkpoint Subtree command instead. If on the other hand, something goes horribly wrong and you need to revert the virtual machine to a previous state then you can right click on the checkpoint and choose the Apply command from the shortcut menu. When you do, Windows will offer you the opportunity to create another checkpoint before applying the checkpoint. That way you can undo the application of the checkpoint if necessary. I recommend shutting down the virtual machine prior to applying a checkpoint. As you can see, it is very easy to create and use Hyper-V checkpoints. Even so, checkpoints are not appropriate for every situation and it is important to understand the implications of using a checkpoint before doing so. The first thing that you need to understand is that a checkpoint is different from a backup. When you create a checkpoint, what you are really doing is creating a differencing disk and flagging the virtual machine s original virtual hard disk as read only. This means that you are not creating a copy of the virtual hard disk, and checkpoints therefore do not protect you against hard disk failures or storage corruption. Another thing that you need to understand is that checkpoints are sometimes affected by other servers on your network. Suppose for a moment that you created How To Work with Hyper-V Checkpoints PART # WP-2022-ENG-A

14 14 Checkpoints are sometimes affected by other servers on your network. a checkpoint of a virtualized domain controller before applying a schema extension. Now, imagine that the schema extension was done incorrectly and you need to revert the Active Directory to its previous state. You could apply the checkpoint, but doing so will only give you the desired results if the checkpoint resides on the only domain controller in the entire domain. If there are other domain controllers in the domain then the Active Directory Replication Service will become an issue. After you apply the checkpoint, the other domain controllers will see the recently reverted domain controller as being outdated. The Active Directory Replication Service will seek to bring that domain controller up to date by replicating all of the Active Directory modifications that have occurred since the time that the checkpoint was created. This includes the unwanted schema extensions. That being the case, you are better off using a traditional backup for your domain controllers (rather than relying on checkpoints) and using an authoritative restoration if necessary. Similarly, you must not use checkpoints for virtual machines that are running applications that maintain state data in memory (such as Exchange Server). Checkpoints do not capture memory contents and applying a checkpoint of such a virtual machine will typically result in data loss or application corruption. If you need to create checkpoints of these types of virtual machines, the only way to do so safely is to create the checkpoint while the virtual machine is shut down. As you can see, checkpoints can be a handy feature, but they can also cause problems unless you fully understand the implications of using them. About the Author Brien Posey is a seven time Microsoft MVP with over two decades of IT experience. As a freelance writer, Posey has written many thousands of articles and written or contributed to several dozen books on a wide variety of IT topics. Prior to going freelance, Posey was a CIO for a national chain of hospitals and healthcare facilities. He has also served as a network administrator for some of the country s largest insurance companies and for the Department of Defense at Fort Knox. When He isn t busy writing, Brien Posey enjoys exotic travel, scuba diving, and racing his Cigarette boat. You can visit his personal Web site at: How To Work with Hyper-V Checkpoints PART # WP-2022-ENG-A