How to Use the Command 'qm guest passwd' (with Examples)
The qm guest passwd command is a useful tool within the QEMU/KVM Virtual Machine Manager environment. It allows administrators to set or modify the password for a user within a specific virtual machine (VM). This utility is particularly advantageous for managing and controlling user access to VMs without needing to log in directly to the virtual system via a console or remote desktop. The command has the capability to set both plain and hashed passwords, providing flexibility in password management.
Use Case 1: Set a Password for a Specific User in a Virtual Machine Interactively
Code:
qm guest passwd vm_id username
Motivation:
Setting a password interactively for a user in a virtual machine is crucial for maintaining security and user authentication protocols. This approach eliminates the need to access the VM directly, streamlining the process of credential management. Administrators often face scenarios where they need to reset or establish a user password due to various administrative duties such as onboarding or adjusting access rights. Using this command helps in swiftly completing such tasks without compromising security protocols.
Explanation:
qm: The command-line tool used within the Proxmox Virtual Environment for managing virtual machines.guest passwd: A subcommand that specifically handles password operations for users on guest VMs.vm_id: This is a placeholder for the virtual machine’s ID. It uniquely identifies the VM you are targeting for password setting.username: The username parameter specifies whose password is being set within the VM.
Example Output:
Upon executing the command, the user will be prompted to enter a new password. The system will not echo the password for security reasons. If successful, no output is given, indicating that the password change was completed without issues.
Use Case 2: Set an Already Hashed Password for a Specific User in a Virtual Machine Interactively
Code:
qm guest passwd vm_id username --crypted 1
Motivation:
Setting a hashed password is essential when security policies dictate that plain-text passwords must not be transmitted or stored. By using a hashed password, administrators can comply with higher security standards and leverage existing password hashes from secure sources, streamlining the integration of the VM into broader security frameworks. This is particularly useful in environments where maintaining password integrity is crucial, such as in enterprise or cloud-based operations.
Explanation:
qm: Just like in the first use case, this is the command-line tool for Proxmox VM management.guest passwd: This part of the command deals specifically with setting or changing a password within the VM.vm_id: The unique identifier for the virtual machine for which the user password is being modified.username: Specifies the username within the selected VM whose password needs updating.--crypted: This option tells the tool that the password provided is already hashed.1: This is a flag that activates the--cryptedoption, confirming that the input password is in hashed form.
Example Output:
After executing the command with the proper parameters, there won’t be any visible output or confirmation if everything proceeds as expected, ensuring the hashed password has been set securely without any intermediate leakages.
Conclusion:
The qm guest passwd command is an essential utility for system administrators managing user accesses in a Proxmox Virtual Environment. It simplifies password management tasks by enabling dynamic password settings without direct VM access. The ability to set both plain and hashed passwords enhances the security and adaptability of this tool, making it invaluable for efficiently handling user credentials in virtualized infrastructures.
