问题
I have lost private key of my AWS instance.I searched the option in console panel.
回答1:
I'm afraid you might be out of luck:
When you launch an instance, you should specify the name of the key pair you plan to use to connect to the instance. If you don't specify the name of an existing key pair when you launch an instance, you won't be able to connect to the instance. When you connect to the instance, you must specify the private key that corresponds to the key pair you specified when you launched the instance. Amazon EC2 doesn't keep a copy of your private key; therefore, if you lose a private key, there is no way to recover it. If you lose the private key for an instance store-backed instance, you can't access the instance; you should terminate the instance and launch another instance using a new key pair. If you lose the private key for an EBS-backed Linux instance, you can regain access to your instance. For more information, see Connecting to Your Linux Instance if You Lose Your Private Key.
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-key-pairs.html
回答2:
Yes, you can't recover the old key. Still, you can generate a new key to access that machine
When we loose private key, You can't login to that machine.
Please follow the below steps to recover the key.
Step 1) Detach your root volume from your machine using AWS console.
Step 2) Launch a fresh EC2 instance(Not from your old machine AMI)
Step 3) Attach your old volume to new EC2 machine
Step 4) Now login to new ec2 machine and mount the old EBS volume
Step 5) Now go to that partition then visit home directory inside that machine and go to .ssh folder.
Step 6) Now generate a new private and public key. Then paste public key into authorized_keys file.
Step 7) Once you done with above steps, detach that volume from this ec2 machine.
Step 8) Now attach this volume to your old machine as root volume
Step 9) Now try to login to your old machine with the newly generated key.
Hope it helps !!
来源：https://stackoverflow.com/questions/32739421/how-to-recover-lost-private-key-of-instance-of-aws-server