Virtual routers save the day

I’m exhausted. For three days I have battled, like Hemingway’s Old Man battling the fish. Like Jacob wrestling the angel for a blessing, which he did obtain at the price of limping the remainder of his life. Like Rocky Balboa facing Apollo Creed (the second time, when he won).

I’ve been battling an evil like no other. It’s not the new massively multiplayer online game “Star Wars: The Old Republic,” but a multiple-subnet Active Directory and Exchange deployment for database availability group (DAG) high-availability configuration.

[ Also on InfoWorld: J. Peter Bruzzese figures Hyper-V in Windows 8 Server could finally beat VMware. | Read the InfoWorld Test Center’s take on Microsoft Windows Server 2008 R2 Hyper-V in the virtualization shoot-out. | Stay abreast of key Microsoft technologies in our Technology: Microsoft newsletter. ]

In wanting to truly grasp the nuances of a DAG failover across sites, I needed to build a lab that exceeds all others I’ve worked with. Typically when you consult, you walk into an existing setup with connectivity in place, or if you are building from the ground up, you might hire folks to handle all the wiring and hardware side for connectivity. But if you’ve ever tried to build a dual-site lab with multiple subnets, you could find yourself struggling simply because your lab may not have the same-quality hardware you expect in a real world deployment.

I was working with two Dell servers (a T310 with two NICs) and a T110 (with a single NIC) setup with Windows Server 2008 R2 with Hyper-V. I had two addressing schemes in play — 192.168.1.x and 10.x.x.x — to illustrate the distinction between the two networks. I had all my 192-address servers on one Hyper-V box and all my 10-address servers on the other Hyper-V box. It was time to get these two communicating with each other and with the Internet.

I grabbed a couple of basic $50 home routers and started setting up the subnets. The problem is that home routers are simply four-port switches that have a single WAN connection out to the Internet. They don’t actually route anything, and it’s impossible to have two subnets with Internet access through these devices. I was stuck.

Typically in a business deployment, I’d go with a Cisco business router to resolve this problem, but here I was forced to look at solutions, both old and new, to make things work. I also had the twist of working with Hyper-V, which sets up virtual networks that are a bit funky compared to the VMware counterpart. I needed additional brainstorming help, so I contacted two colleagues at TrainSignal, David Davis (a noted vExpert) and Ed Liberman (a technical speaker and network infrastructure guru), to see what they recommended. I also consulted a great article to better understand basic networking, Hyper-V, and virtual switches to help me master the concepts.

Davis recommended I use my dual-NIC server to handle routing and pointed me to a virtual router from Vyatta. I downloaded and installed it into Hyper-V without an issue. There’s a GUI side if you have the subscription version, but I had the open source, free version, so I had to set up my router through the command line. It was a blast from the past, establishing static routes through the command line, especially in Linux, but once I got ahold of some online command assistance, it was pretty simple. The Vyatta virtual router is a solid option because it doesn’t take a ton of resources from your Hyper-V server, which you most likely want to leave for your production virtual machines.

Virtual routers are great on the enterprise level because they can save you money on the hardware of a fully functional system. Also, as virtual boxes, they also take up no room in your network. The negative is that you may have to learn enough command-line configuration to kick off the GUI features, then you can work through a browser interface.

Liberman, my Windows guru, recommended I use Microsoft’s routing and remote access (RRAS) solution through Windows Server 2008 R2. I liked the idea and saw that others were using virtual machines to do this, but I wanted to save my VMs for Exchange servers for my DAG. Instead, I installed it directly on the Hyper-V parent system — probably not a best practice.

The benefit is that I felt comfortable immediately because it’s Windows. Wizards and action items helped me configure the server and establish static routes where necessary, until I had a fully functional setup. The value of RRAS is that it’s included with Windows, so you don’t have to pay extra to turn a dual-NIC server into an enterprise router, even if only for a lab setup.

One other tip from Liberman: If you’re doing this in a home office and have a family Internet connection, you’ll want to use subnetting to ensure both sides of your networks can access the Internet. In my case, the 192-address network can easily get out through my home router that uses 192 address, but the 10-address network is jammed because the home router doesn’t know how to respond. By splitting the 192.168.1.x network with a 255.255.255.248 subnet mask, I could’ve accomplished both goals of securing Internet connectivity from both sides with multiple subnets and two distinct sites on either side of the router. Brilliant stuff.

Everything is now up and running, and I can move forward with my DAG testing.

Sleepless nights are part of the IT geek’s life, and we wear them like badges. Do you have a tale from the trenches you’d like to share? Share your war story in the comments (Add a comment) below.

This article, “Virtual routers save the day,” was originally published at InfoWorld.com. Read more of J. Peter Bruzzese’s Enterprise Windows blog and follow the latest developments in Windows at InfoWorld.com. For the latest business technology news, follow InfoWorld.com on Twitter.