L15 - Cloud Computing 1 (Part 3: Operations)

Question 1

What is meant by Staging Environment?

Answer 1

• Environment where a version of the software is run before being moved to end users (production)
• Company stakeholders can give feedback on product in the staging environment before moving to production.

Question 2

What is meant by Staging in the Cloud?

Answer 2

Many companies don’t own their own staging environment, but rather rent it in the cloud. This is cheaper, more flexible, and more scalable.

Question 3

What are the benefits of staging in the cloud?

Answer 3

• Cheaper
• Flexible
• More scalable

Question 4

What are 5 benefits of using Cloud Computing? Define each…

Answer 4

Broad Network Access:
- Cloud is accessible across a variety of networks from any location.
- Networks are faster and more reliable than they used to be, so cloud is almost always accessible regardless of where you are.

On demand, self service:
- Cloud architecture means that anyone can acquire Virtual Machines and start interacting with or working in the cloud.

Measure service:
- Only pay for what you use
- Providers monitor usage and billed accordingly

Rapid elasticity:
- Cloud architecture enables scaling dynamically and rapidly depending on business requirements.
- This caters for uncertain demand of companies in current companies, and their often requirement to scale very fast. Especially with start-ups.

Resource pooling:
- Providers assign virtual machines to physical ones.
- Enables software multi-tenancy to be achieved.

Question 5

Define Software Multi-tenancy…

Answer 5

Cloud architecture in which a single software running in the cloud serves multiple clients at once.

Question 6

What is Serverful Computing?

Answer 6

Cloud provider provisions users with physical or virtual servers to manage in the cloud

Question 7

What is Serverless Computing?

Answer 7

Cloud computing architecture where cloud providers provide users to compute in the cloud through cloud based servers, VM’s and containers.

Question 8

What are the 3 models of Serverful Computing?

Answer 8

IaaS → Cloud provider gives access to bare servers.

PaaS → Cloud provider gives access to servers with operating systems and tools.

SaaS → Cloud provider gives access to applications on a subscription basis.

Question 9

What are the implementations used in Serverful Computing? Give pros and cons of each…

Answer 9

• Virtual Machines:
  
  • Pro: Enables multi customers to run VM’s on one physical device, enable greater scalability.
  • Con: Deploying is long and computationally expensive since need to boot OS for each one.
• Containers:
  
  • Run on shared kernel
  • Pro: Much cheaper than VM’s. More lightweight.
  • Con: Have to cluster users by OS. No isolation means central point of failure. If things go wrong, it can be very bad.

Question 10

What is the Cost Model of Serverful Computing?

Answer 10

• Rent VM’s for a period of time
• You are responsible for loading up software and using it as you wish.
• Comparable to renting a car

Question 11

In Serverful Computing, is a Microservice Implementation more expensive on VM’s or Containers?

Answer 11

• VM’s are expensive.
• Containers are cheaper and more efficient.

Question 12

What are the models of Serverless Computing?

Answer 12

BaaS → Cloud provider gives access to features such as authentication and databases

FaaS → Cloud provider runs functions in response to requests and events

Question 13

In the context of Serverless Computing, what does Serverless mean?

Answer 13

Refers to not the absence of servers, but rather to the fact that operation concerns are left for the cloud provider to deal with.

Question 14

Explain the implementation of Serverless Computing…

Answer 14

Typically makes use of hidden containers to run custom code.

Question 15

What is the cost model of serverless computing?

Answer 15

Charges customers for execution time on a pay-as-you-go basis.

Question 16

What are the methods of implementing a microservice architecture using serverless computing?

Answer 16

Method 1 → Map a single microservice to a single function instance in the cloud

Method 2 → Map a single microservice instance to multiple function instances in the cloud

Question 17

What issues may occur when implementing a microservice architecture using serverless computing?

Answer 17

• Maintenance problems → Keeping track of instances
• Performance problems → Keeping warm instances