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A Hyper-V cluster can provide high availability for virtualized workloads, automating the process of migrating virtual machines to healthy servers when a node fails. Administrators can choose among several options for setting up a virtual cluster, but System Center Virtual Machine Manager offers the greatest functionality and simplest ease of use. In this tip we'll take a look at a few elements that you should always take into consideration before deploying a Hyper-V cluster through SCVMM.
Laying the groundwork for Hyper-V nodes
In order to deploy a Hyper-V cluster with System Center Virtual Machine Manager (SCVMM), you must first ensure that you have the correct conditions for running Hyper-V nodes. Hyper-V nodes must run on a supported Windows OS. If you intend to cluster Windows Server 2012 R2 or later OSes, you must use SCVMM 2012, which can only be installed on a Windows Server 2012 R2 OS. If you want to install a Hyper-V cluster on Windows Server 2012 but are running SCVMM 2012 Service Pack 1 or earlier, you'll have to first build the cluster outside of SCVMM and then add it to SCVMM.
Next, make sure your Hyper-V nodes are available in the same SCVMM host group. Since SCVMM does not support nodes from different groups, you cannot take one node from host group "x" and another from host group "y." You can check whether your nodes are in the same group when the Create Cluster Wizard prompts you to select Hyper-V nodes from a SCVMM host group.
You'll also need to enable multipath I/O (MPIO). MPIO allows each Hyper-V node access to Fiber Channel and iSCSI storages devices. Since SCVMM can't enable MPIO on Hyper-V nodes added under SCVMM management, you'll have to install MPIO on each node before starting the Create Cluster Wizard, preferably before adding Hyper-V hosts under SCVMM.
Setting up storage devices
When using the Create Cluster Wizard, you will be asked to select shared storage disks from a storage category. It's important to categorize the storage devices in a way that makes it easier to select less expensive disks for less critical workloads and expensive storage for critical workloads.
Once storage has been classified in SCVMM, the next step is to create logical units. Logical units must be created and allocated on the SCVMM host group in which your Hyper-V nodes reside. This is necessary because allocating storage on a SCVMM host group allows you to display the list of shared storage disks from the Create Cluster Wizard. You can create logical units by clicking the "Create Logical Units" button found in the Fabric workspace in SCVMM. You must create at least two storage disks: a Witness Disk and a Cluster Data Disk. The Create Cluster Wizard will automatically mark any disk larger than 500 MB as a Witness Disk. The Cluster Data Disk stores VM files such as XML, Virtual Hard Disk and Hyper-V Virtual Hard Disk files.
Define network and failover settings
Microsoft made iSCSI Target Server available for organizations that do not wish to buy physical SAN devices for virtualized workloads. If you are using iSCSI Target Server or iSCSI SAN as the shared storage for a Hyper-V cluster, make sure to enable and start the iSCSI initiator service on Hyper-V nodes that are going to be part of the cluster. You must also enable iSCSI exceptions on firewall devices. If you neglect to enable iSCSI initiator service on Hyper-V nodes, the SCVMM Create Cluster Wizard will not show the logical storage devices and will fail to attach storage to the Hyper-V cluster.
You can install the Failover Clustering feature on Hyper-V nodes in advance. If you choose to do so, SCVMM will skip installing the Failover Clustering feature. In some cases, SCVMM might fail to install the Failover Clustering feature on Hyper-V nodes, even if you haven't installed it in advance. Should this occur, manually install the Failover Clustering feature on all Hyper-V nodes and then restart failover cluster creation via SCVMM.
SCVMM is capable of automatically creating a virtual switch on Hyper-V nodes as part of the Create Cluster Wizard. Virtual switches are created from the preexisting VM Network in SCVMM. To display the list of VM Networks from which the virtual switch will be created, there are a few steps you'll need to follow. First, go to the property page of each Hyper-V node and click on the Hardware tab. Next, expand the network adapters and click on a network adapter for which you want to create a virtual switch. Select Logical Network Connectivity and, finally, click Select a VM Network.
Since VM requires a cluster name and IP address to assign to the Hyper-V cluster, you'll need to designate these before starting the Create Cluster Wizard.
SCVMM makes it easier to run both Hyper-V and VMware
Building a virtual infrastructure with SCVMM 2012 R2
How to build a free Hyper-V failover cluster