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101-500 Exam - Question 28


Which of the following properties of a Linux system should be changed when a virtual machine is cloned? (Choose two.)

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Correct Answer: CE

When cloning a virtual machine, two critical properties that should be changed to avoid conflicts and security vulnerabilities are the D-Bus Machine ID and the SSH host keys. The D-Bus Machine ID is a unique identifier for the machine, and if not changed, it can lead to conflicts within networked environments. Similarly, the SSH host keys are used for secure communication between machines, and duplicating these keys across cloned machines can create serious security risks. Changing these properties ensures that each cloned virtual machine operates securely and correctly within the network.

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JilNOptions: CE
May 25, 2021

Additional information. We must change the following as well. 1. The hostname 2. NIC MAC address 3. NIC IP address 4. Any item employing a UUID. 5. Machine ID 6. Configuration settings on the clone that employ any item in the list above

SScott
Oct 21, 2021

Yes, C and E are right The recommendation is to ensure the D-Bus Machine ID is unique. https://wiki.debian.org/MachineId#:~:text=The%20machine%20id%20is%20something%20that%20is%20frequently%20missed%20to%20change%20when%20cloning%20a%20machine https://unix.stackexchange.com/questions/402999/is-it-ok-to-change-etc-machine-id https://askubuntu.com/questions/1179897/ubuntu-18-04-guests-which-cloned-by-virtualbox-have-the-same-ip-but-different-ma For security reasons, E SSH host keys must not be duplicated https://blog.technodrone.cloud/2013/01/the-ssh-key-problem-with-cloned-linux.html

slobber20
Aug 1, 2020

Disagree see: https://www.thegeekdiary.com/centos-rhel-7-how-to-change-the-machine-id/

ellen_AA
Mar 6, 2021

I agree, but the question mentions the "D-bus machine-id"

MashkoorQadirOptions: CE
Dec 16, 2020

host SSH keys needs to replace because the host name IP of the cloned machine will be changed.

MashkoorQadirOptions: CE
Dec 16, 2020

/root/ permission remains same in any case.

tzahiOptions: CE
Mar 21, 2022

Machine ID is a unique hexadecimal 32 character string given to your machine during installation. So it should be changed if the machine is cloned to prevent duplicate ID on a network. SSH keys are unique to each server/client and also should be changed to securely SSH

oladessyOptions: DE
Jul 31, 2020

D and E is the correct answer, can anyone explain why C is correct

SScott
Oct 21, 2021

As for D, don't see this being something that necessarily needs to be changed. https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/configuring_and_managing_virtualization/cloning-virtual-machines_configuring-and-managing-virtualization#:~:text=Note%20that%20disk%20images%20for%20VMs%20created%20in%20the%20system%20connection%20of%20libvirt%20are%20by%20default%20located%20in%20the%20/var/lib/libvirt/images%20directory%20and%20owned%20by%20the%20root%20user

LazylinuxOptions: CE
Mar 24, 2022

Below link states all https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/virtualization_deployment_and_administration_guide/cloning_virtual_machines

NinymoOptions: CE
Mar 24, 2024

Answer: CE