AWS - Create new instance from AMI, but lost keys?

1
votes

I have an AMI that I created a few weeks ago. I want to launch a new AWS EC2 instance and provide that AMI as the image. Problem is, I can't ssh into that box now.

I have tried to attach a new key pair when launching the new instance, but it's as if the configuration of the SSH keys on the box is ignoring my newly attached key pair.

Is there a way to overcome this issue?

I know my new key pair works, I've tested it on a totally blank new instance and I can SSH in just fine.

Any help is greatly appreciated!

1
amazon-web-servicesamazon-ec2key-pair
Is the security group for your EC2 instance allowing connections on port 22 from your IP address? – spg
Not port 22 no, I use a different port, but the security group does allow it. Networking shouldn't be an issue though. I can reach the instance, it just says "Permission denied (public key)". – user1840352
What linux distro is the AMI? What is the user did you try to ssh in as? – helloV
Distro is Ubuntu 14.04 – user1840352

1 Answers

4
votes

The keypair is only copied to the Amazon EC2 instance the first time that the disk is booted. Since you have already booted from that disk (or a disk from which the image was made), it will not copy the keypair again.

You will need to copy a new keypair to the /home/ec2-user/.ssh directory. This can be done by attaching the EBS volume to a different instance:

  • Stop the instance (Instance 1)
  • Detach the EBS volume (make a note of the device identifier, eg /dev/xvda)
  • Attach the EBS volume to another Linux instance (Instance 2)
  • Edit the /home/edc2-user/.ssh/authorized_keys file and insert your desired public key
  • Detach the EBS volume from Instance 1, re-attach it to Instance 2
  • Start Instance 1 and ssh to it using your new keypair

See documentation: Connecting to Your Linux Instance if You Lose Your Private Key