Virtualization is the engine underneath every IaaS cloud. This set covers Type 1 and Type 2 hypervisors, full, para and hardware-assisted virtualization, the Popek and Goldberg requirements, live migration techniques and memory management tricks like ballooning and page sharing. It includes small numerical problems on downtime and consolidation, making it useful for GATE, university exams, UGC NET and systems interviews.
How to practise: read each question and tap the option you think is correct. You will see right away whether you got it, along with a short explanation, and your score is tracked at the bottom of the screen. This set has 18 questions.
Topics covered in this set
- Type 1 vs Type 2 hypervisors
- Full, para and hardware-assisted virtualization
- Popek and Goldberg requirements
- Pre-copy and post-copy live migration
- Ballooning, page sharing and overcommit
- Server consolidation and I/O virtualization
Cloud Computing MCQs with answers and explanations
Q1. Which of the following is a Type 1 (bare-metal) hypervisor?
a) Oracle VirtualBox
b) VMware Workstation
c) VMware ESXi
d) Parallels Desktop
Q2. A Type 2 hypervisor differs from a Type 1 hypervisor mainly because it
a) Runs as an application on top of a conventional host operating system
b) Needs no CPU support at all
c) Cannot run more than one guest
d) Is always faster than Type 1
Q3. In para-virtualization, the guest operating system
a) Runs completely unmodified using binary translation
b) Has its kernel modified to issue hypercalls to the hypervisor instead of executing sensitive instructions
c) Is replaced by a container runtime
d) Emulates a different CPU architecture
Q4. Before hardware virtualization extensions existed, how did full virtualization on x86 handle sensitive instructions of an unmodified guest kernel?
a) By using paravirtual drivers
b) By using containerisation
c) By rebooting the host
d) By binary translation of guest kernel code
Q5. According to Popek and Goldberg, an instruction set architecture can be efficiently virtualized with trap-and-emulate if
a) The set of sensitive instructions is a subset of the set of privileged instructions
b) The set of privileged instructions is empty
c) All instructions execute only in user mode
d) The machine has no paging hardware
Q6. Intel VT-x and AMD-V primarily provide
a) Faster solid-state disk access
b) Dedicated graphics acceleration
c) Built-in disk encryption
d) A new CPU execution mode letting hypervisors run unmodified guests and trap sensitive operations without binary translation
Q7. In pre-copy live migration, what happens during the final stop-and-copy phase?
a) The VM is shut down and rebooted on the destination host
b) The VM is briefly paused while the remaining dirty pages and CPU state are transferred
c) The guest disk is reformatted
d) All memory is copied again from scratch
Q8. In the final round of a pre-copy migration, 200 MB of dirty pages remain and the migration link sustains 1000 MB/s. Ignoring CPU state, what is the approximate downtime?
a) 20 ms
b) 200 ms
c) 2 s
d) 4 s
Q9. Which migration technique transfers the CPU state first, resumes the VM at the destination and then fetches memory pages on demand from the source?
a) Pre-copy migration
b) Cold migration
c) Post-copy migration
d) Storage-only migration
Q10. A hypervisor reclaims memory by inflating a driver inside the guest that allocates pages, forcing the guest OS to free or swap its own memory. This technique is
a) Memory ballooning
b) Page colouring
c) Transparent huge pages
d) Memory-mapped I/O
Q11. A host has 64 GB of RAM and runs 20 VMs, each configured with 4 GB of memory. What is the memory overcommit ratio?
a) 0.8
b) 1.5
c) 2.0
d) 1.25
Q12. Which technique saves host memory by detecting identical memory pages across VMs and keeping a single copy-on-write copy?
a) Ballooning
b) Swapping
c) Transparent page sharing
d) NUMA pinning
Q13. Another common name for a hypervisor is
a) Virtual Machine Monitor
b) Virtual Memory Manager
c) Volume Management Module
d) Virtual Message Middleware
Q14. Running an unmodified ARM guest operating system on an x86 host requires
a) Para-virtualization
b) Hardware-assisted virtualization alone
c) Emulation that translates the guest instruction set
d) Memory ballooning
Q15. In the Xen hypervisor, the privileged domain that manages other guests and usually hosts the physical device drivers is
a) DomU
b) Dom0
c) Ring 3
d) The hypercall table
Q16. KVM is best described as
a) A Type 2 hypervisor available only on Windows
b) A container runtime
c) A block storage protocol
d) A Linux kernel module that turns the Linux kernel into a hypervisor using hardware virtualization extensions
Q17. A company has 40 physical servers averaging 10% CPU utilisation. If workloads are consolidated as VMs onto identical hosts targeting 80% utilisation, how many hosts are needed?
a) 4
b) 5
c) 8
d) 10
Q18. Which technology allows a single PCIe network adapter to present multiple virtual functions that can be assigned directly to different VMs?
a) SR-IOV
b) RAID
c) VLAN tagging
d) iSCSI
Quick revision notes
- Type 1 (bare metal): ESXi, Xen, Hyper-V, KVM. Type 2 (hosted): VirtualBox, VMware Workstation.
- Full virtualization: unmodified guest (binary translation or hardware assist). Para-virtualization: modified guest using hypercalls.
- Popek-Goldberg: sensitive instructions must be a subset of privileged instructions.
- Pre-copy: iterative memory copy then short stop-and-copy. Post-copy: CPU state first, pages on demand.
- Downtime approx = remaining dirty data / link bandwidth.
- Overcommit ratio = total configured VM memory / physical memory.
- Hosts needed = total utilisation demand / target utilisation per host.
- Memory reclamation: ballooning, page sharing (KSM), hypervisor swapping.
Frequently asked questions
What is the difference between Type 1 and Type 2 hypervisors?
A Type 1 hypervisor runs directly on the hardware and is used in data centres for performance and isolation. A Type 2 hypervisor runs as an application on a host OS and is mainly used on desktops for testing and development.
What is live migration of a virtual machine?
Live migration moves a running VM from one physical host to another with only a very short pause. It is used for maintenance, load balancing and power saving without interrupting users.
Why is virtualization important for cloud computing?
Virtualization lets one physical server be safely divided among many isolated tenants, which enables resource pooling, rapid provisioning and high utilisation. Without it, elastic multi-tenant IaaS would be impractical.
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