Add aliases to ssh using session manager

[vshimoda]

example usage

 $ aws ssh i-xxxxxxxxxxxxxxxxxxxxxx

Starting session with SessionId: vshimoda-xxxxxxxxxxxxxxxxxxxxxx
sh-4.2$ 

[virgilwashere]

You can achieve this without spawning a subshell:

  ssm start-session --target

However, this is NOT actually an ssh session, so I would suggest renaming the alias:

shell =
  ssm start-session --target

NB: An SSM SSH session would require something similar to this in ~/.ssh/config

# SSH over Session Manager
host i-*
    IdentityFile ~/.ssh/ec2-instance-sshkey.pem
    ProxyCommand sh -c "aws ssm start-session --target %h --document-name AWS-StartSSHSession --parameters 'portNumber=%p'"