AWS module 6.6 Container services

Question 1

What is a container and how does it differ from a virtual machine?

Answer 1

A container packages an application with its dependencies and runs on a shared OS.

VM:
* Includes full OS
* Heavier

Container:
* Lightweight
* Faster startup
* Shares host OS

Question 2

Why are containers more efficient than virtual machines?

Answer 2

Because they share the host OS, reducing overhead and improving performance.

Question 3

What is Amazon ECS?

Answer 3

Elastic Container Service is a managed container orchestration service used to run and manage containers.

Question 4

What is container orchestration?

Answer 4

Managing deployment, scaling, networking, and lifecycle of containers automatically.

Question 5

What are the key components of ECS architecture?

Answer 5

• Cluster
• Task definition
• Task
• Service
• Container

Question 6

What is a task definition in ECS?

Answer 6

A blueprint that defines:
* Container image
* CPU/memory
* Ports
* Environment variables

Question 7

What is a task in ECS?

Answer 7

A running instance of a task definition.

Question 8

What is a service in ECS?

Answer 8

A component that ensures a specified number of tasks are running continuously.

Question 9

What is an ECS cluster?

Answer 9

A logical group of resources (EC2 or Fargate) where containers run.

Question 10

What is Amazon ECR?

Answer 10

Elastic Container Registry — a Docker image storage repository.

Question 11

Why is ECR important in container workflows?

Answer 11

It stores container images so ECS can pull and run them.

Question 12

Describe the flow of running a container using ECS.

Answer 12

Build container image
Push to ECR
Create task definition
Run task/service in ECS
ECS pulls image and runs container

Question 13

What are the two launch types in ECS?

Answer 13

• EC2 launch type
• Fargate launch type

Question 14

What is ECS EC2 launch type?

Answer 14

You manage EC2 instances that run containers.

Question 15

What is ECS Fargate launch type?

Answer 15

Serverless container execution where AWS manages infrastructure.

Question 16

Compare EC2 launch type vs Fargate.

Answer 16

EC2:
* More control
* Requires management

Fargate:
* No server management
* Easier but less control

Question 17

Why would a company choose Fargate over EC2?

Answer 17

To avoid managing servers and focus only on running containers.

Question 18

What is a key benefit of EC2 launch type over Fargate?

Answer 18

Greater control over infrastructure and cost optimisation.

Question 19

What is container scaling and how does ECS support it?

Answer 19

Increasing/decreasing number of running containers.

ECS supports scaling via:
* Services
* Auto Scaling

Question 20

What is load balancing in ECS?

Answer 20

Distributing traffic across multiple containers for performance and reliability.

Question 21

How does ECS achieve high availability?

Answer 21

By running containers across:
* Multiple instances
* Multiple Availability Zones

Question 22

What is the role of networking in ECS?

Answer 22

To allow containers to communicate internally and externally.

Question 23

Why is container portability important?

Answer 23

Containers can run anywhere consistently (dev, test, production).

Question 24

What is a Docker image?

Answer 24

A packaged file containing application code + dependencies used to create containers.

Question 25

What happens if a container fails in ECS?

Answer 25

The service automatically restarts or replaces it.

Question 26

A company wants full control over servers and cost optimisation. Which ECS launch type?

Answer 26

EC2 launch type

Question 27

A startup wants minimal management and fast deployment. Which option?

Answer 27

Fargate

Question 28

A system must always have 5 containers running. What ECS feature ensures this?

Answer 28

ECS Service

Question 29

Why are containers ideal for microservices architecture?

Answer 29

Because they allow independent deployment, scaling, and isolation of services.

Question 30

Explain how ECS, ECR, and Fargate work together in a containerised system.

Answer 30

* ECR stores container images * ECS manages deployment * Fargate runs containers without servers