How to SSH to an AWS EC2 Instance Running Linux from a CircleCI 2 Build
If you use EC2 to host your application, and a tool like CircleCI to automate the deployment of new versions of your application, chances are, you've run into the problem of Circle not being able to SSH into your servers.
The problem is Circle could change the public IP of your runner for every new Build which prevents it from being able to access (SSH) the EC2 Instance. Unfortunately, Circle is not able to provide a list of public IP addresses to whitelist on a Security Group attached to the EC2 Instance. More on this here: https://discuss.circleci.com/t/circleci-source-ip/1202