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inac
Asked: 2021-10-21 19:14:46 +0800 CST

No associated key pair, add key pair to EC2 with no key pair

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How do you add an existing key to a live EC2 instance that has no key pair?

I have tried using Session Manager to vi /.ssh/authorized_keys and add in the public key of the pair, but I get this error:

"~/.ssh/authorized_keys"
"~/.ssh/authorized_keys" E212: Can't open file for writing

Is this something that has to be done using the console?

No associated key pair
This instance is not associated with a key pair. Without a key pair, you can't connect to the instance through SSH.
You can connect using EC2 Instance Connect with just a valid username. You can connect using Session Manager if you have been granted the necessary permissions.
amazon-ec2 public-key private-key key

1 Answers

  1. Since you’ve got Systems Manager configured you’re half-way there. The only thing standing between you and success is the fact that Systems Manager Session opens the session as ssm-user and you’ll need to do sudo -u ec2-user -i first and once you're logged in as ec2-user do the subsequent steps.

    Then you may have to create the ~ec2-user/.ssh directory if it doesn’t exist and chmod it to 700.

    And finally you can add the public key to ~ec2-user/.ssh/authorized_keys and chmod that file to 600.

    That should do the trick :)

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