Building Hyper-V Hosts: Hardware and OS

mshv-overview

Hyper-V, Microsoft’s hypervisor platform, has really grown up in the last few years. Introduced with Windows Server 2008, Microsoft has iterated its hypervisor platform reaching version “3.0” with Windows Server 2012. Version 3.0 has often been considered the magic version number for Microsoft as to when the product is not only good enough, but also a contender.  Then they further fine-tuned the product with Windows Server 2012 R2 making it a worthy VMware competitor. Hyper-V does not match feature for feature with VMware, but on most of the features that matter the hypervisors are equals.

To implement Hyper-V host clusters in your environment requires many elements to be integrated properly. Thankfully Microsoft PFE’s and the community maintain a Best Practices Checklist on TechNet that you can use to make your Hyper-V deployment a success.  I recommend you read through it carefully a number of times during your design phase of your Hyper-V deployment. Missing a crucial component could make the difference between success and failure of the project. I’m going to highlight a few key points from the checklist.

Since a hypervisor is actually going to be running on bare metal, we must select hardware that will provide the power, features, and stability that we need. We need to begin by selecting the hardware from a vendor that is listed as being officially supported for running Hyper-V. Start with the Windows Server Catalog to see if your preferred vendor hardware and components are certified. ws2012r2_logo_72x90Verify the CPU model meets the virtualization requirements. Windows Server 2012 R2 is licensed by socket, but with Windows Server 2016 Microsoft will switch to a per-core licensing model similar to SQL. Until Windows Server 2016 is released (and your EA renews) the strategy is to buy as many cores per socket as you can afford to maximize your licensing. The similar strategy should be used for memory: buy as much memory as you can afford. Typically the first resource to be used up is memory. Use the Datacenter edition if you plan to implement many more than two VM’s as it gives you unlimited guest Windows server licenses. The standard edition includes licenses for two VM’s.

Strongly consider using 10 GbE or higher network interface cards, if you can afford it, to allow for fast live migration of large VM’s, and especially if you plan to use SMB or iSCSI SAN. Also consider buying NIC’s that support RDMA (RoCE) for SMB direct for higher performance, especially if implementing SoFS SAN.  Select NIC’s from manufacturers who are known to have reliable drivers. Bad drivers will destroy your Hyper-V environment. We will dive deeper into networking of Hyper-V hosts and guests in a later post.

When installing the OS, aim to use the server core interface to minimize patches and vulnerabilities. Manage the server from an administrative system with the RSAT tools and PowerShell. Ensure rollups and applicable hotfixes are applied to your hosts. And just to state the obvious, keep your Hyper-V clustered hosts at the same patch level. The parent partition or management OS should have the minimal roles and features necessary including Hyper-V, Failover Clustering, MPIO, and SNMP where applicable. The only other installed items should be manufacturer’s drivers and utilities along with backup, operations, and antivirus agents. Be extremely careful about installing antivirus on your Hyper-V hosts. The antivirus exceptions must be setup correctly or you may at best degrade performance and at worst corrupt your virtual machines.  One list tip about the OS of your Hyper-V hosts: protect your hosts by limiting who can log on to them. Using server core will keep the away the server admins “who know enough to be dangerous.”

In later blog posts we will cover network configuration for the host and for guests, including converged networking with iSCSI.

Thanks to Aidan Finn (@joe_elway) and other authors of the Windows Server 2012 Hyper-V: Installation and Configuration Guide.

Read Aidan Finn’s Best Practices for Hyper-V.