How-To

Upgrading Windows Server 2012 EC2 Instances, Part 1: Planning

Brien demonstrates the process of upgrading AWS EC2 instances running Windows Server 2012 R2 to newer OSes.

• By Brien Posey
• 11/30/2021

Windows Server 2012 and 2012 R2 are approaching their scheduled end of life in 2023. As such, organizations need to begin considering how they are going to migrate away from Windows Server 2012 and move workloads onto a newer OS. I wanted to take the opportunity to demonstrate the process of upgrading AWS EC2 instances running Windows Server 2012 R2 to newer OSes.

I'm going to cover the hands on portion of the upgrade process in Parts 2 and 3. For right now though, I want to talk about some important things that you will need to consider before jumping into an OS upgrade.

One of the first things that you need to check when preparing for an OS upgrade is the hardware resources that are available on the EC2 instance. There are two main things that you need to look for with regard to hardware:

• First, workloads tend to change over time and it is possible that the virtual hardware that was initially used might not be all that well suited for the workload as it exists today. As such, this is a good time to consider whether you need to use a larger or smaller instance type. Changing instance types is beyond the scope of this blog series, but I plan to cover it in a future post.
• The second thing that you need to consider with regard to hardware is whether there is enough space available on the boot drive to accommodate the OS upgrade. When you create a Windows Server virtual machine (VM) instance, EC2 defaults to creating a 30 GB boot drive. This isn't going to be large enough to accommodate an OS upgrade, even if nothing is running on the instance other than the Windows Server OS. You are most likely going to end up needing to expand the boot volume. Again, this is a topic that I intend to cover in the near future. Incidentally, Amazon recommends making sure that your instance is equipped with at least two vCPUs and 4 GB of RAM if you are going to attempt an in-place upgrade.

Another thing that you will need to consider is whether you are going to be performing an in-place upgrade or a clean install. An in-place upgrade is often preferred because it allows you to retain your applications and your OS configuration. Even so, there are situations in which a clean installation is preferred. This is especially true if the instance is currently experiencing stability issues or if the server is running an application that does not support the new OS (meaning that both the OS and the applications will have to be upgraded). For the purposes of this blog series, I am going to be walking through an in-place upgrade.

Amazon also recommends that you check to make sure that your instance is equipped with the latest network drivers prior to attempting an in-place upgrade. Performing a driver upgrade probably won't be necessary if your VM instance is relatively new. However, there is a chance that a Windows Server 2012 machine is running the older PV style drivers and will need to be upgraded. You can find information on PV driver upgrades.

I also strongly recommend that you create a full backup of your instance prior to attempting an OS upgrade. I have personally never experienced a problem while upgrading and instance's OS, but any time that you do something as invasive as an OS upgrade there is a very real chance that something will go wrong during the upgrade process or that problems will manifest themselves later on. Having a reliable backup ensures that you can put everything back to normal in the event that something goes wrong with your OS upgrade.

Finally, before you begin an OS upgrade it is extremely important to disable any low-level software that you have running on the instance. This can include things like anti-malware software, backup agents and security software. These types of software have been known to cause OS upgrades to fail. This is especially true for antivirus software and security software because the upgrade process can sometimes be misinterpreted as malicious activity.

Now that I have discussed some of the finer points of the OS upgrade planning process, I want to turn my attention to performing an in-place upgrade. Before you read the second blog post in this series however, I strongly recommend reading Amazon's documentation.

Part 2 is now available here, and Part 3 is now available here.