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27 Nov 2020, 13:25
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A cloud computing environment leverages many fundamental technologies. One such technology is virtualization, which allows for a number of virtual machines to share the physical resources of a single physical machine. A large number of physical machines with virtualization could be networked together to form what is known as a cloud environment. A virtual machine that is hosted on a physical machine is often referred to as a guest virtual machine.
The increase in the number of organizations using the same physical host machine for guest virtual machines creates opportunities for certain types of attacks. One example is a side channel attack, in which one virtual machine monitors how another uses shared processor memory to infer sensitive information.
A technique that allows a virtual machine to accommodate increased resource needs or protect against such attacks is migration. Migration is the process of moving a guest virtual machine from one physical host to another. Two migration types considered through experimentation were cloning migration and offline migration. To compare different migration types, a Denial of Service (DoS) scenario was created to increase the resource needs of a host and cause a migration of a virtual machine from one physical host to another.
The increase in the number of organizations using the same physical host machine for guest virtual machines creates opportunities for certain types of attacks. One example is a side channel attack, in which one virtual machine monitors how another uses shared processor memory to infer sensitive information.
A technique that allows a virtual machine to accommodate increased resource needs or protect against such attacks is migration. Migration is the process of moving a guest virtual machine from one physical host to another. Two migration types considered through experimentation were cloning migration and offline migration. To compare different migration types, a Denial of Service (DoS) scenario was created to increase the resource needs of a host and cause a migration of a virtual machine from one physical host to another.
Based on the information provided, which of the following statements is most strongly supported?
| Offline and cloning are the only available types of virtual machine migration. | |
| In the experiment, a Denial of Service (DoS) scenario was created to trigger migration for comparison purposes. | |
| For all virtual machine migration types, the total migration time is equal to the guest virtual machine’s downtime. | |
| Side channel attacks pose a greater risk to virtual machines than Denial of Service (DoS) attacks. | |
| Virtual machines eliminate the need for physical machines in cloud environments. |
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Official Answer
In the experiment, a Denial of Service (DoS) scenario was created to trigger migration for comparison purposes.
27 Nov 2020, 13:25
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Official Solution:
Offline and cloning are the only available types of virtual machine migration.
• Tab 1 states that offline and cloning migrations were tested in the experiment, but it does not claim they are the only available types. Other migration types may exist. Not supported.
In the experiment, a Denial of Service (DoS) scenario was created to trigger migration for comparison purposes.
• Tab 1 clearly states that a Denial of Service (DoS) scenario was created in order to compare different migration types. This was a constructed condition used to trigger migration during the experiment. Supported.
For all virtual machine migration types, the total migration time is equal to the guest virtual machine’s downtime.
• Tabs 2 and 3 confirm that total time equals downtime for offline and cloning migrations. However, no information is provided about all migration types, so the statement overgeneralizes. Not supported.
Side channel attacks pose a greater risk to virtual machines than Denial of Service (DoS) attacks.
• Tab 1 defines what a side channel attack is, but the tabs do not compare the severity or risk level of side channel attacks versus DoS attacks. No such conclusion can be drawn. Not supported.
Virtual machines eliminate the need for physical machines in cloud environments.
• Tab 1 explains that virtual machines run on physical machines. It does not state or suggest that physical machines are unnecessary. In fact, physical machines are essential to cloud environments. Not supported.
Correct answer:
Based on the information provided, which of the following statements is most strongly supported?
"In the experiment, a Denial of Service (DoS) scenario was created to trigger migration for comparison purposes."
Bunuel
Offline and cloning are the only available types of virtual machine migration.
• Tab 1 states that offline and cloning migrations were tested in the experiment, but it does not claim they are the only available types. Other migration types may exist. Not supported.
In the experiment, a Denial of Service (DoS) scenario was created to trigger migration for comparison purposes.
• Tab 1 clearly states that a Denial of Service (DoS) scenario was created in order to compare different migration types. This was a constructed condition used to trigger migration during the experiment. Supported.
For all virtual machine migration types, the total migration time is equal to the guest virtual machine’s downtime.
• Tabs 2 and 3 confirm that total time equals downtime for offline and cloning migrations. However, no information is provided about all migration types, so the statement overgeneralizes. Not supported.
Side channel attacks pose a greater risk to virtual machines than Denial of Service (DoS) attacks.
• Tab 1 defines what a side channel attack is, but the tabs do not compare the severity or risk level of side channel attacks versus DoS attacks. No such conclusion can be drawn. Not supported.
Virtual machines eliminate the need for physical machines in cloud environments.
• Tab 1 explains that virtual machines run on physical machines. It does not state or suggest that physical machines are unnecessary. In fact, physical machines are essential to cloud environments. Not supported.
Correct answer:
Based on the information provided, which of the following statements is most strongly supported?
"In the experiment, a Denial of Service (DoS) scenario was created to trigger migration for comparison purposes."
03 Apr 2025, 16:36
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This MSR question and its solutions have been completely revised and improved.
