Change key pair for ec2 instance

Question

How do I change the key pair for my ec2 instance in AWS management console? I can stop the instance, I can create new key pair, but I don't see any link to modify the instance's key pair.

Answer 1

I went through this approach, and after some time, was able to make it work. The lack of actual commands made it tough, but I figured it out. HOWEVER - much easier approach was found and tested shortly after:

1. Save your instance as an AMI (reboot or not, I suggest reboot). This will only work if EBS backed.
2. Then, simply start an instance from this AMI and assign your new Keyfile.
3. Move over your elastic IP (if applicable) to your new instance, and you are done.

Answer 2

Run this command after you download your AWS pem.

ssh-keygen -f YOURKEY.pem -y

Then dump the output into authorized_keys.

Or copy pem file to your AWS instance and execute following commands

chmod 600 YOURKEY.pem

and then

ssh-keygen -f YOURKEY.pem -y >> ~/.ssh/authorized_keys

Answer 3

I have tried below steps and it worked without stopping the instance. My requirement was - as I have changed my client machine, the old .pem file was not allowing me to log in to the ec2 instance.

1. Log in to the ec2 instance using your old .pem file from the old machine. Open ~/.ssh/authorized_keys

You will see your old keys in that file.

2. ssh-keygen -f YOUR_PEM_FILE.pem -y It will generate a key. Append the key to ~/.ssh/authorized_keys opened in step#1. No need to delete the old key.

3. From AWS console, create a new key pair. Store it in your new machine. Rename it to the old pem file - reason is old pem file is still associated with the ec2 instance in AWS.

All done.

I am able to log in to the AWS ec2 from my new client machine.

Answer 4

In case you are using ElasticBeanstalk platform, you can change the keys by going:

• Elastic Beanstalk panel
• Configuration
• Instances (cog top-right)
• EC2 key pair

This will terminate current instance and creates new one with chosen keys/settings.

Answer 5

I believe the simpliest aproach is to :

1. Create AMI image of original iinstance.
2. Launch new EC2 instance using AMI image (from step 1) with new key pair.
3. Login to new EC2 instance with new key.

Answer 6

The simplest solution is to copy the contents of

~/.ssh/id_rsa.pub

into your AWS instance's authorized_keys at

~/.ssh/authorized_keys

This will allow you to ssh into the EC2 instance without specifying a pem file for the ssh command. You can remove all other keys once you've tested connecting to it.

If you need to create a new key to share it with someone else, you can do that with:

ssh-keygen -t rsa

which will create the private key.pem file, and you can get the public key of that with:

ssh-keygen -f private_key.pem -y > public_key.pub

Anyone who has private_key.pem will be able to connect with

ssh [e-mail] -i private_key.pem