What to do if you lose your EC2 key pair
If you lose your EC2 key pair, you can register another key pair with your existing instance. You don't have to create a new instance.
The procedure for linux / MacOS is shown as an example.
Create a new key pair
Creating a new key pair is not mandatory. Skip if you want to use another existing key pair.
- Access the AWS Management Console
- ʻEC2
> Go toNetwork & Security>Key Pair` - Click "Create Key Pair"
- Enter the key pair name and click "Create Key Pair"
- pem file is downloaded
- Move the pem file to the appropriate directory and set the appropriate permissions
$ mv xxxxx.pem ~/.ssh/
$ chmod 400 ~/.ssh/xxxxx.pem
For Windows
Create a public key
$ ssh-keygen -y -f ~/.ssh/xxxxx.pem- Copy all the output public keys including "ssh-rsa"
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQClKsfkNkuSevGj3eYhCe53pcjqP3maAhDFcvBS7O6V
hz2ItxCih+PnDSUaw+WNQn/mZphTk/a/gU8jEzoOWbkM4yxyb/wB96xbiFveSFJuOp/d6RJhJOI0iBXr
lsLnBItntckiJ7FbtxJMXLvvwJryDUilBMTjYtwB+QhYXUMOzce5Pjz5/i8SeJtjnV3iAoG/cQk+0FzZ
qaeJAAHco+CY/5WrUBkrHmFJr6HcXkvJdWPkYQS3xqC0+FmUZofz221CBt5IMucxXPkX4rWi+z7wB3Rb
BQoQzd8v7yeb7OzlPnWOyN0qFU0XA246RA8QFYiCNYwI3f05p6KLxEXAMPLE
For Windows
Modify user data for EC2 instances
- Stop EC2 instance
- Click
Action>Instance Settings> ʻEdit user data`
- If there is already defined user data, save it somewhere
- Paste the script below into the user data
Content-Type: multipart/mixed; boundary="//"
MIME-Version: 1.0
--//
Content-Type: text/cloud-config; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="cloud-config.txt"
#cloud-config
cloud_final_modules:
- [users-groups, once]
users:
- name: username
ssh-authorized-keys:
- PublicKeypair
Modify * ** users.name ** and ** PublicKeypair ** and click "Save"
-
users.name ... ec2-user etc
-
PublicKeypair ... The public key you just created
-
Launch an instance
-
After booting, check that you can ssh connection using the downloaded pem file
ssh -i ~/.ssh/xxxxx.pem [email protected]
-
Stop the instance
-
Delete all the scripts pasted earlier, including the public key
-
Paste the saved user data if it exists
-
Click "Save"
-
Launch an instance
reference
[How do I connect to my Amazon EC2 instance if I lose my SSH key pair after the first boot?](Https://aws.amazon.com/jp/premiumsupport/knowledge-center/user-data-replace -key-pair-ec2 /)
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