SSH access and metadata in GCP - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding SSH Key Metadata in GCP

In Google Cloud Platform, when you add an SSH public key to a VM instance's metadata, what does this metadata entry control?

A It allows the specified user to SSH into the VM using the corresponding private key.

B It disables password authentication for all users on the VM.

C It restricts SSH access only to users with the Google Cloud Console account.

D It automatically installs the SSH server software on the VM instance.

💡 Hint

Think about what SSH keys do in general for secure access.

Adding an SSH public key to the VM's metadata authorizes the corresponding private key holder to connect via SSH. It does not install software or restrict access to console users only.

❓ Configuration

intermediate

Configuring SSH Access via Project-wide Metadata

You want to allow a new user to SSH into all VM instances in your GCP project without adding keys to each VM individually. Where should you add the user's SSH public key?

A Add the SSH public key to each VM instance's local metadata individually.

B Add the SSH public key to the project-wide metadata under the 'ssh-keys' entry.

C Add the SSH public key to the firewall rules to allow SSH traffic.

D Add the SSH public key to the service account attached to the VM instances.

💡 Hint

Think about how project-wide metadata affects all instances.

Project-wide metadata applies to all VM instances in the project, so adding SSH keys there grants access to all VMs without per-instance configuration.

❓ security

advanced

Preventing Unauthorized SSH Access via Metadata

Which of the following practices best prevents unauthorized SSH access to your GCP VM instances when using SSH keys in metadata?

A Allow SSH access only from any IP address to avoid connection issues.

B Disable the SSH service on all VM instances and use only serial console access.

C Add all users' SSH keys to the default service account metadata.

D Regularly rotate SSH keys and remove unused keys from instance and project metadata.

💡 Hint

Think about key management and minimizing access.

Rotating keys and removing unused keys reduces risk of compromised keys being used. Disabling SSH or allowing all IPs is not practical or secure.

❓ service_behavior

advanced

Effect of Removing SSH Keys from Metadata

If you remove a user's SSH public key from the project-wide metadata, what happens when that user tries to SSH into a VM instance that does not have their key in its local metadata?

A The user will be prompted to enter a password instead of using the key.

B The user will still be able to SSH because keys are cached on the VM.

C The user will be denied SSH access because their key is no longer authorized.

D The VM instance will automatically add the user's key back from the Google Cloud Console.

💡 Hint

Consider how SSH key authorization works with metadata.

Removing the key from project-wide metadata revokes access unless the key exists in local metadata. Keys are not cached permanently on VMs.

❓ Architecture

expert

Designing Secure SSH Access with Metadata and OS Login

You want to enforce centralized SSH access control using Google Cloud OS Login instead of managing SSH keys in metadata. Which statement correctly describes the behavior when OS Login is enabled on VM instances?

A SSH keys in instance or project metadata are ignored; access is controlled by IAM roles assigned to users.

B SSH keys in metadata override OS Login settings and grant access regardless of IAM roles.

C OS Login disables SSH access completely and requires use of the Google Cloud Console only.

D OS Login requires manually adding SSH keys to each VM's local metadata for access.

💡 Hint

Think about how OS Login integrates with IAM and metadata.

When OS Login is enabled, SSH key management moves to IAM roles and user accounts, ignoring SSH keys in metadata for access control.