A key setup task that is required if you are going to running any EC2 instances in your AWS account is to establish one or more EC2 key pairs, which for Linux EC2 instances, can be used to define an SSH key pair that grants SSH access to your EC2 instances.

When you create an EC2 key pair, an SSH public/private key pair will be automatically generated, with the SSH public key being stored as a named EC2 key pair in AWS, and the corresponding SSH private key downloaded to your local client.  If you subsequently create any EC2 instances and reference a named EC2 key pair at instance creation, you will be able to automatically use the associated SSH private key to access your EC2 instances.