Key pairs for SSH access in AWS - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the primary purpose of an AWS key pair?

In AWS, what is the main reason you create a key pair?

A To manage user permissions in IAM

B To configure network routing tables

C To securely connect to EC2 instances via SSH

D To encrypt data stored in S3 buckets

💡 Hint

Think about how you access a virtual server securely.

A key pair in AWS is used to securely connect to EC2 instances using SSH. It consists of a public key stored by AWS and a private key you keep safe.

❓ Configuration

intermediate

Which AWS CLI command creates a new key pair and saves the private key locally?

You want to create a new key pair named my-key and save the private key to a file. Which AWS CLI command should you use?

A aws ec2 create-key-pair --key-name my-key --query 'KeyMaterial' --output text > my-key.pem

B aws ec2 create-key --name my-key --output json > my-key.pem

C aws ec2 generate-key-pair --name my-key > my-key.pem

D aws ec2 new-key-pair --key-name my-key --save my-key.pem

💡 Hint

Look for the official AWS CLI command to create key pairs and how to extract the private key.

The correct command is aws ec2 create-key-pair. Using --query 'KeyMaterial' extracts the private key material, and redirecting output saves it to a file.

❓ Architecture

advanced

How to securely manage SSH access to multiple EC2 instances in a production environment?

You have many EC2 instances and want to manage SSH access securely and efficiently. Which approach is best?

A Disable SSH access and rely only on HTTP connections

B Use AWS Systems Manager Session Manager to connect without SSH keys

C Create a unique key pair for each instance and distribute private keys to users

D Use a single key pair for all instances and share the private key with all users

💡 Hint

Consider AWS services that allow secure access without managing SSH keys.

AWS Systems Manager Session Manager lets you connect to instances securely without SSH keys, improving security and simplifying access management.

❓ security

advanced

What happens if you lose the private key of an AWS key pair used for EC2 access?

You lost the private key file (.pem) for an EC2 instance's key pair. What is the impact and best recovery method?

A You can reset the key pair directly from the EC2 instance settings

B You can download the private key again from AWS console anytime

C AWS automatically regenerates the private key and emails it to you

D You lose SSH access; best practice is to create a new key pair and update the instance's authorized keys

💡 Hint

Think about AWS security design and private key handling.

AWS does not store your private key. Losing it means you cannot SSH in. The recovery is to create a new key pair and update the instance's authorized keys manually or via Systems Manager.

❓ service_behavior

expert

What is the behavior when you delete an AWS key pair that is associated with running EC2 instances?

You delete a key pair in AWS that is currently associated with several running EC2 instances. What happens to SSH access on those instances?

A Nothing changes; instances keep the public key and allow SSH access

B SSH access is immediately revoked and connections fail

C Existing SSH sessions remain, but new SSH connections using that key fail

D AWS automatically replaces the deleted key pair on instances with a new one

💡 Hint

Consider how AWS stores public keys on instances and the effect of deleting key pairs in the console.

Deleting a key pair in AWS only removes it from the AWS console. The public key remains on the EC2 instances, so SSH access using the private key still works unless you manually remove the key from the instance.