computing

1. School of Science and Technology
MIDDLESEX UNIVERSITY
EXAMINATION PAPER
Academic Year 2015/2016 (Aug/Sept)
CCE4370
Virtualisation and Cloud Technology
Dr Jonathan Loo
Time allowed: 2 hours
Total number of questions: 5
Instructions to candidates: Answer any 3 questions.
Each question is worth a maximum of 25 marks.
Materials provided:
Equipment permitted: Non-programmable calculators
Total number of pages: 6 (including front Cover)
EXAM PAPER CANNOT BE REMOVED FROM THE EXAM ROOM
No books, paper or electronic devices are permitted to be brought into the examination room
other than those specified above.
Candidates are warned that credit cannot be given for work that is illegible

2. Question 1
An increasing number of organisations in industry and business are now adopting cloud
systems. Answer the following questions regarding cloud computing:
a) List the main characteristics of cloud computing systems.
[5 marks]
b) Discuss different ways for cloud service providers to maximise their revenues.
[5 marks]
c) Characterise the following three cloud computing models:
i) Describe Infrastructure as a Service (IaaS).
[5 marks]
ii) Describe Platform as a Service (PaaS).
[5 marks]
iii) Describe Software as a Service (SaaS).
[5 marks]

3. Question 2
a) Define how system availability is measured.
[5 marks]
b) Consider a computer cluster that has little availability support. Upon a node failure,
the following sequence of events takes place:
• Step 1: The entire system is shut down and powered off.
• Step 2: The faulty node is replaced if the failure is in hardware.
• Step 3: The system is powered on and rebooted.
• Step 4: The user application is reloaded and rerun from the start.
c) Assume one of the cluster nodes fails every 100 hours. Other parts of the cluster
never fail. Steps 1 through 3 take two hours. On average, the mean time for step 4 is
two hours. What is the availability of the cluster? What is the yearly failure cost if
each one-hour downtime costs £2000?
[10 marks]
d) Following Part (b), assume that the cluster now has much increased availability
support. Upon a node failure, its workload automatically fails over to other nodes. The
failover time is only six minutes. Meanwhile, the cluster has hot swap capability: The
faulty node is taken off the cluster, repaired, replugged, and rebooted, and it rejoins
the cluster, all without impacting the rest of the cluster. What is the availability of this
ideal cluster, and what is the yearly failure cost?
[10 marks]

4. Question 3
a) Describe CPU virtualisation.
[5 marks]
b) Hardware-assisted CPU virtualisation is a technique that attempts to simplify
virtualisation.
i) Describe the fundamental of hardware-assisted CPU virtualisation.
[5 marks]
ii) Why the hardware-assisted CPU virtualisation is important?
[5 marks]
iii) What is Intel VT-x technology? Briefly describe the technology.
[5 marks]
c) Which virtualisation technique is shown in Figure Q3? Explain the operation of such
technique.
[5 marks]
Figure Q3

5. Question 4
a) MapReduce is a software framework which supports parallel and distributed
computing on large data sets. Explain the following 2 important functions of the
MapReduce framework.
i) Map function
[2.5 marks]
ii) Reduce function
[2.5 marks]
b) Figure Q4 shows an execution of a practical MapReduce programme called
WebVisCounter. The program counts the number of times users connect to or visit a
given website using a particular operating system (e.g. Windows or Mac). A single line
of a typical web server log file is fed into the MapReduce framework, which is shown
in the “Line offset” column.
Here, you are required to demonstrate your understanding of MapReduce execution
by working out the outcome of each task/box shown in Figure Q4 (e.g. MAP1, MAP2,
PAR1, PAR2, etc.) where the final outcome should match the expected result at the
Output stage.
[20 marks]
Figure Q4

6. Question 5
a) OpenStack cloud platform was built based on the Service-oriented Architecture (SOA).
i) Describe the service-oriented architecture (SOA).
[5 marks]
ii) Explain the operational nature of SOA.
[3 marks]
b) Describe the Representational State Transfer (REST) architecture.
[5 marks]
c) With the aid of Figure Q5, discuss the following four important principles of REST
architecture.
Figure Q5
i) Resource identification through URIs
[3 marks]
ii) Uniform, Constrained Interface
[3 marks]
iii) Self-Descriptive Message
[3 marks]
iv) Stateless interactions
[3 marks]