Monday, March 14, 2011

Networking and Hyper-V

Recently, we had a discussion in a user group where I participate.

I asked the members which competence/skills they defined as most valuable for them.
Most of the guys answered networking. (one guy did actually mention SQL security, but that`s what he does for a living).

A quite interesting answer in these days, I must say.
While the world is occupied by virtualization technologies, clouds, and the – as a Service models, these guys are still attached to their beloved networking skills.

And I agree.
Networking is still the most used skill in my day-to-day work.
I would like to give you an example of one my latest Hyper-V projects for a customer.
They needed to save some of their old physical servers. Running critical workloads and had no backups. The servers were located in three different subnets, and one of them was in a secure zone.

That brings us back to the topic: networking
The Hyper-V host was installed with 4 NICs.
1 NIC dedicated for host management
1 NIC dedicated for the network
1 NIC dedicated for the network
1 NIC dedicated for the network

To be able to convert these physical machines to virtual, we have to use SCVMM. (Disk2VHD is not suited when converting Windows Server 2000 since there is no VSS service available)
And SCVMM requires an Active Directory Domain, and to be able to convert a physical server to virtual and place it on a Hyper-V host, the Hyper-V host requires to be member of a domain.

The domain and the required servers were connected through an Internal Virtual Network in Hyper-V.
We created 3 External Virtual Networks, and attached the NICs to the proper networks in the physical switch.
The SCVMM server was equipped with 3 vNICs. One NIC for the internal virtual network, one NIC for the External network, and one NIC for the External network.
We assigned static IP addresses to the vNICs and were able to connect to the source, and do the P2V conversion and place them safely on the Hyper-V host.
All this was done in an evening. And the most fun of every P2V conversion, is when the costumer says that there are no changes, and wondering when we`ll get started.
-          The machines are now virtual and identical as they were the old physical one.

There are some best practices when it comes to networking in Hyper-V

Dedicated NICs
The Hyper-V host should have a dedicated NIC for host management. Securing stability, cluster management, and to not impact the workloads running in Hyper-V

The VMs running in Hyper-V should have at least one dedicated NIC function as a virtual switch. Cause when you`re creating an External Virtual Network in Hyper-V, you are actually binding that physical NIC to the virtual network. And attach a vNIC to every VM that should communicate on that network. If you are running VMs with heavy network traffic – you could also have a dedicated NIC for this VM – meaning that no other VMs should connect to that vSwitch.

When you are dealing with Failover Clustering combined with Hyper-V, you are able to connect to the shared storage through iSCSI. This brings additional requirements for NICs on the Hyper-V hosts. The VMs would be located on this shared storage, and the NICs intended for this should be of high quality. It`s common to use NIC teaming (though not supported by Microsoft), or MPIO for redundancy and more throughput.
You should also add additional NICs for Live Migration, and Cluster heartbeat communication.

Networking is one of the most important part of an infrastructure. It`s relevant for the system administrator, virtualization administrator, system architect, and – the network administrator.
So to be able to manage the clouds, datacenters, and also your SQL servers - you still need some basic networking skills.
(Even the SQL-guy agreed that networking was important to his job)


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