I made a little twitter thread here (shameless ploy for followers) (I work for AWS): https://twitter.com/jrhunt/status/1144402767890436096

* Works on amzn linux 2 - installed by default on newer versions

* otherwise: $ sudo yum install ec2-instance-connect

* The SSH public keys are only available for one-time use for 60 seconds in the instance metadata.

* you can send up your own SSH keys `aws ec2-instance-connect send-ssh-public-key`

* cloudtrail logs connections for auditing

* doesn't support tag based auth but it's on the roadmap

* plans to enable it in popular linux distros in addition to amzn linux 2

Install local client:

$ aws s3 cp s3://ec2-instance-connect/cli/ec2instanceconnectcli-latest.tar.gz .

$ pip install ec2instanceconnectcli-latest.tar.gz

$ mssh instanceid