I am working on a project to move classic EC2 to a VPC of it's own. I have read that using ClassicLink allows me to keep the security groups and potentially communicate with classic EC2 instances within this newly created VPC to other EC2 instances outside of the VPC.

My question is this: I am pondering whether to keep going this route of using ClassicLink and connecting classic EC2 instances to this new VPC or to create a brand new VPC and use the current EC2s and recreate the Security Groups (I'd rather go with this option to get with the times). What are the pros and cons to both options? In addition, say I go with the latter and there is a classic EC2 instance I would need to do some kind of VPC Peering or even classic Link on that particular instance. Is that possible with creating a current VPC?

Thanks for the help.


Both options are really the same.

The way the ClassicLink works is that you create a new VPC, create new Security Groups (VPC-SG), and then link the EC2 instances to the new VPC via assigning them a VPC-SG.

It is like adding a layer over your existing instances. EC2 instances keep using EC2-SG to connect to each other, but use the VPC-SG to connect to the new resources in the VPC.

  • Thanks!! I did observe i can adopt preexisting security groups using classic link..
    – ryekayo
    Mar 14 '17 at 14:22

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.