There is a disturbing consistency in the kinds of project requests I see these days. Organizations call me because they are in the midst of their first transition to cloud, and they are spending many months planning out their exact AWS environment and all the security controls “before we move any workloads up”. More often than not some consulting firm advised them they need to spend 4-9 months building out 1-2 virtual networks in their cloud provider and implementing all the security controls before they can actually start in the cloud.

This is exactly what not to do.

As I discussed in an earlier post on blast radius, you definitely don’t want one giant cloud account/network with everything shoved into it. This sets you up for major failures down the road, and will slow down cloud initiatives enough that you lose many of the cloud’s advantages. This is because:

  • One big account means a larger blast radius (note that ‘account’ is the AWS term – Azure and Google use different structures, but you can achieve the same goals). If something bad happens, like someone getting your cloud administrator credentials, the damage can be huge.
  • Speaking of administrators, it becomes very hard to write identity management policies to restrict them to only their needed scope, especially as you add more and more projects. With multiple accounts/networks you can better segregate them out and limit entitlements.
  • It becomes harder to adopt immutable infrastructure (using templates like CloudFormation or Terraform to define the infrastructure and build it on demand) because developers and administators end up stepping on each other more often.
  • IP address space management and subnet segregation become very hard. Virtual networks aren’t physical networks. They are managed and secured differently in fundamental ways. I see most organizations trying to shove existing security tools and controls into the cloud, until eventually it all falls apart. In one recent case it became harder and slower to deploy things into the company’s AWS account than to spend months provisioning a new physical box on their network. That’s like paying for Netflix and trying to record Luke Cage on your TiVo so you can watch it when you want.

Those are just the highlights, but the short version is that although you can start this way, it won’t last. Unfortunately I have found that this is the most common recommendation from third-party “cloud consultants”, especially ones from the big firms. I have also seen Amazon Solution Architects (I haven’t worked with any from the other cloud providers) not recommend this practice, but go along with it if the organization is already moving that way. I don’t blame them. Their job is to reduce friction and get customer workloads on AWS, and changing this mindset is extremely difficult even in the best of circumstances.

Here is where you should start instead:

  • Accept that any given project will have multiple cloud accounts to limit blast radius. 2-4 is average, with dev/test/prod and a shared services account all being separate. This allows developers incredible latitude to work with the tools and configurations they need, while still protecting production environments and data, as you pare down the number of people with administrative privileges.
    • I usually use “scope of admin” to define where to draw the account boundaries.
  • If you need to connect back into the datacenter you still don’t need one big cloud account – use what I call a ‘bastion’ account (Amazon calls these transit VPCs). This is the pipe back to your data center; you peer other accounts off it.
  • You still might want or need a single shared account for some workloads, and that’s okay. Just don’t make it the center of your strategy.
  • A common issue, especially for financial services clients, is that outbound ssh is restricted from the corporate network. So the organization assumes they need a direct/VPN connection to the cloud network to enable remote access. You can get around this with jump boxes, software VPNs, or bastion accounts/networks.
  • Another common concern is that you need a direct connection to manage security and other enterprise controls. In reality I find this is rarely the case, because you shouldn’t be using all the same exact tools and technologies anyway. There is more than I can squeeze into this post, but you should be adopting more cloud-native architectures and technologies. You should not be reducing security – you should be able to improve it or at least keep parity, but you need to adjust existing policies and approaches.

I will be writing much more on these issues and architectures in the coming weeks. In short, if someone tells you to build out a big virtual network that extends your existing network before you move anything to the cloud, run away. Fast.