For those of you who like scripting your installs as much as I do there’s something you should be aware of when installing 2012 on Windows 2012 R2. I don’t remember coming across it in Windows 2012 RTM, but maybe I’m wrong. All the same though…

When you install SQL 2012 on Windows 2012 R2 you’ll get an error part way through saying that you have to install NetFx3.
Normally you’d do this in PS as part of your script like this:

Add-WindowsFeature net-framework-features 

Unfortunately you’ll get an error when you try to install this by default on a fresh Windows install. Look at the pic below…

You can see that while the net-framework-features are present, the net-framework-core is ‘Removed’. This is actually what you’re looking for. So where do you get it? On the Windows DVD of course. So now your PS code to install this features looks like this… I’m assuming your Windows DVD in in the D:

Add-WindowsFeature net-framework-features -source D:\Sources\sxs

Now that leaves us with a problem. How do we get the Windows guys to install this for us by default when they give us our box? Because I’ve had very limited success getting them to change their image in a lot of places and they don’t want to go in afterward and install anything manually. So here’s what you do.
Get a hold of the Windows media just once. You can pull it from your MSDN account, or from the network share where they keep the Windows install, or just ask them for it. When you get it copy that entire folder to your SQL install folder. It’s only 275MB. Now you can have a copy of it for yourself and you don’t have to bother them about it. And being able to pass in the -source param means you can point it to any directory you like.
So now the top of your PS install script will look like this:

Add-WindowsFeature as-net-framework
Add-WindowsFeature net-framework-features -source D:\Sources\sxs

Now, if you’re doing your install through the wizard you will have to do this step. And I think I’ve heard that setup will complete just fine if you don’t install this feature, but I haven’t confirmed that personally yet. I also suspect that if it does complete manually just fine without it that it may go ahead and complete if it scripted, but it may shoot up an error in the log. And there’s just no reason to create errors when you don’t have to.

I’ll try to find time to test a couple different scenarios and let you know how it goes… you know, in all my copious free time.