L6b - Cloud Systems

Question 1

Amazon’s elastic block storage (EBS)

What is it?

Is it persistent?

Answer 1

Amazon Elastic Block Store (Amazon EBS) is a storage service for Amazon EC2 instances (VM).

short: EBS is a disk for VM

persistent

Question 2

Amazon’s elastic file system (EFS)

What is it?

Is it persistent?

Answer 2

It allows you to create and share file systems that can be accessed concurrently by multiple EC2 instances, providing a shared file storage solution for your applications.

persistent

Question 3

Amazon’s S3 storage

What is it?

Is it persistent?

Answer 3

persistent object storage (object storage means, objects are accessed via HTTP GET/PUT/DELETE)

short: slow but cheap storage

persistent

Question 4

What is S3 commonly used for?

Answer 4

1. backup
2. data archiving
3. content storage for websites
4. as a data lake for analytics

Question 5

What are two purposes of load balancers?

Answer 5

performance: distribute load across machines
availability: send work only to available machines

Question 6

What is DMZ?

Answer 6

It acts as a buffer zone to add an extra layer of security by isolating publicly accessible services, such as web servers or email servers, from the internal network to minimize the potential impact of security breaches.

Question 7

What is the purpose of DMZ? What does it provide?

Answer 7

1. protect the rest of the system
2. firewall access
3. create network groups
4. controlled SSH access
5. virtual network

Question 8

What is Azure’s Jump Box?

Answer 8

you access only to one VM (the Jump Box) and then access the rest of the machine over the Jump Box

You can control and monitor access, restrict IPs that can connect, etc.

extra: Bastion even better (no public IP needed to connect)

Question 9

The tiers in charge of processing requests are built as a pool of VMs. What are those called?

Answer 9

compute tiers

Question 10

Why do we have them?

Answer 10

For isolation. Tiers are isolated from each other for security.

extra: often, a tier can only be accessed form the tier above

Question 11

What are different approached to implement data tier?

Answer 11

1. using an VM and running a database on it
2. using a data service (no need to maintain the system, many additional features such as automatic replication, etc.)
3. growing trend is towards managed data services (cloud native databases)

Question 12

Amazon’s Route 53?

Answer 12

A distributed, reliable DNS

1. maps systems inside the cloud to URLs and external addresses
2. implements flow and traffic control according to user defined policies (location, latency, round robin, failures status, etc.), includes geo-routing (routing requests to other data centers)

Question 13

Why do we need DNS resolution for the cloud using an additional service?

Answer 13

Most of the system in the cloud sit on virtual private networks…

but systems needs to be visible from the outside

Question 14

What are the different storage needs?

Answer 14

1. local disk (EBS)
2. local file system (EFS)
3. large storage (S3)
4. archival (S3 Glacier)

Question 15

What is a CDN?

Answer 15

A CDN manages traffic to web sites so that the content is downloaded from a near-by location (stored or cached there).

Question 16

availability sets

Answer 16

VMs you deploy on Azure are distributed across multiple isolated hardware nodes in a cluster

Question 17

availability zones

Answer 17

separate physical locations within an Azure region

Each zone consists of one or more datacenters equipped with independent power, cooling, and networking.

Question 18

Amazon’s region

Answer 18

AWS has the concept of a Region, which is a physical location around the world where we cluster data centers.

short: multiple, isolated, and physically separate AZs within a geographic area

Question 19

Amazon’s availability zone

Answer 19

We call each group of logical data centers an Availability Zone.