How can I connect multiple EC2 instance together in AWS?

Question

I created four EC2 free-tier instances of Windows Server 2019 to be used for a Windows Server lab. Two of those instances will be used as workstations. The other two instances will be a Domain Controller and a second server, possibly used as a File Server.

Since I am new to AWS, but not new to the cloud in general, how do I configure things so all four instances talk to each other? I do not see a need to connect them to my home network, but want to be able to connect remotely and run my lab scenarios that way.

Thanks! Chris

Answer 1

First, please note that there is no such thing as an "EC2 free-tier instance". The AWS Free Tier is a pricing discount that gives 750 hours per month of free usage of certain Amazon EC2 instances. So, if you are running 4 instances for the entire month, only one quarter of the charges will be covered by the Free Tier. (But you can stop the instances when they aren't being used to reduce your costs.)

Amazon EC2 instances within the same VPC can communicate with each other. However, you will need to configure the Security Groups associated with each instance to permit this communication. The simplest way might be to assign the same Security Group to all instances, and then add an Inbound rule to the Security Group that permits connections from the Security Group itself. This is required because the rules of the Security Group apply to each instance individually, so there needs to a rule that allows inbound communications from the same security group when it is associated with another instance.

You mention that you want to be able to "connect remotely and run my lab scenarios". This will also require you to configure the Security Group to permit the necessary connections from your home IP address, such as ports for RDP and maybe HTTP/S.