Week 7 - Cloud Computing

Question 1

Many enterprises do not own the computing infrastructure that provides their staging/production environment. What do they do instead?

Answer 1

Rent it in “the cloud”

Question 2

What 5 things does cloud architecture provide?

Answer 2

Broad network access
On-demand self service
Measured service
Rapid elasticity
Resource pooling

Question 3

Cloud architecture provides broad network access. What does this mean?

Answer 3

The cloud is available over standard networks, including Virtual Private Networks (VPNs)

Question 4

Cloud architecture provides on-demand self service. What does this mean?

Answer 4

Customers can easily acquire virtual machines, usually on a “drug-dealer” (free go) pricing model

Question 5

Cloud architecture provides measured service. What does this mean?

Answer 5

The provider monitors and measures usage for optimisation and billing purposes

Question 6

Cloud architecture provides rapid elasticity. What does this mean?

Answer 6

Customers can easily acquire or release virtual machines in response to changing demand

Question 7

Cloud architecture provides resource pooling. What does this mean?

Answer 7

Providers assign virtual machines to physical ones, so achieving multitenancy

Question 8

How does cloud computing offer more assurance than on-premises computing?

Answer 8

Staffed by top people
Built with the best kit
Hardened by continual hacking

Question 9

What have been the two phases of cloud computing?

Answer 9

Serverful computing and serverless computing

Question 10

What 3 things does serverful computing consider?

Answer 10

Serverful models, serverful implementation, the serverful cost model

Question 11

Name 3 models of serverful computing

Answer 11

Infrastructure-as-a-Service (IaaS)

Platform-as-a-Service (PaaS)

Software-as-a-Service (SaaS)

Question 12

Describe Infrastructure-as-a-Service (IaaS).

Answer 12

Cloud provider gives access to bare servers

Question 13

Describe Platform-as-a-Service (PaaS).

Answer 13

Cloud provider gives access to servers with operating systems and tools

Question 14

Describe Software-as-a-Service (SaaS).

Answer 14

Cloud provider gives access to applications on a subscription basis

Question 15

What do implementations of serverful computing make use of?

Answer 15

Multi-tenancy

Question 16

Multi-tenancy is implemented by virtualisation. What does this process use?

Answer 16

Virtual machines, containers, and orchestration and version control

Question 17

How are virtual machines run?

Answer 17

On a physical machine by a hypervisor which maps virtual resources to physical ones, ensuring that they are shared fairly

Question 18

How are containers run?

Answer 18

On a physical machine by the operating machine, which maps container resources to physical ones, ensuring that they are shared fairly

Question 19

What is the serverful cost model?

Answer 19

Charging customers for resource allocation on a rental basis

Question 20

Name two ways to implement serverful microservices.

Answer 20

Run a single microservice on a single virtual machine

Run a single microservice in a single container

Question 21

What does serverless computing consider?

Answer 21

Serverless models, serverless implementation, the serverless cost model

Question 22

Name 2 serverless computing models.

Answer 22

Backend-as-a-Service (BaaS)

Function-as-a-Service (FaaS)

Question 23

Describe Backend-as-a-Service (BaaS).

Answer 23

Cloud provider gives access to services such as authentication or database storage

Question 24

Describe Function-as-a-Service (FaaS).

Answer 24

Cloud provider runs custom code in response to requests or events

Question 25

What do implementations of serverless computing typically make use of?

Answer 25

“Hidden” containers to run custom function code

Question 26

What does serverless computing mean?

Answer 26

Most operational concerns are left to the cloud provider

Question 27

What is the serverless cost model?

Answer 27

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

Question 28

Give two ways to implement a serverless microservice.

Answer 28

Map a single microservice instance to a single function instance

Map a single microservice instance to multiple function instances

Question 29

What problems might mapping a single microservice instance to multiple function instances cause, and how can these be resolved?

Answer 29

Maintenance problems (keeping track of instances) and performance problems (keeping “warm” instances)

Can be resolved with an API gateway acting as a proxy through which HTTP requests and responses are used to make function calls and to return function results

Question 30

What does the Infrastructure-as-Code (IaC) approach do?

Answer 30

Configures (virtual) infrastructure using executable code, which can be stored in version control, with all the usual benefits