An administrator deploys a new virtual machine. After logging in, she notices that the VM's time differs from the host time. What is the most likely cause?

An administrator deploys a new virtual machine. After logging in, she notices that the VM's time differs from the host time. What is the most likely cause?

• A. The virtual machine cannot communicate with the network.
• B. The guest tools are not installed.
• C. The vNIC is not configured correctly.
• D. The VLAN tag is incorrect.

Answer: (B)

Time synchronization inside a virtual machine is typically handled by integration components installed in the guest OS. When those guest tools (or the equivalent integration services) aren’t installed or enabled, the VM doesn’t receive the host’s time updates and relies on its own clock, which can drift relative to the host. That mismatch is the common reason you’d see the VM’s time differ after deployment. Installing the guest tools enables time synchronization with the hypervisor (and often with an external time source as a backup) to keep clocks aligned. The other options don’t directly affect timekeeping: a misconfigured virtual NIC or VLAN tag isn’t related to clock synchronization, and while lack of network access could prevent external time sources from updating the clock, the scenario specifically points to the absence of the guest integration components as the most likely cause.

Time synchronization inside a virtual machine is typically handled by integration components installed in the guest OS. When those guest tools (or the equivalent integration services) aren’t installed or enabled, the VM doesn’t receive the host’s time updates and relies on its own clock, which can drift relative to the host. That mismatch is the common reason you’d see the VM’s time differ after deployment. Installing the guest tools enables time synchronization with the hypervisor (and often with an external time source as a backup) to keep clocks aligned. The other options don’t directly affect timekeeping: a misconfigured virtual NIC or VLAN tag isn’t related to clock synchronization, and while lack of network access could prevent external time sources from updating the clock, the scenario specifically points to the absence of the guest integration components as the most likely cause.