DevOps and Containers

Question 1

What are containers?

Answer 1

Containers are a method of operating system virtualization that enables you to run an application and its dependencies in resource-isolated processes.

Question 2

How do containers work?

Answer 2

Build a container image
With containers, you can package your code and its dependencies into a container.

Automate testing and deployment
Because you are using an image that can be thought of as a template, you can standardized your code. When you make changes, think of them as consistent building blocks.

Run anywhere
Containers package your code with the configuration files and dependencies it needs to consistently run in any environment. Containers also provide process isolation that lets you granularly set CPU and memory utilization for better use of compute resources.

Scale quickly
Each container runs as a separate process that shares the resources of the underlying operating system. This enables containers to start and stop quickly.

Question 3

What is Docker?

Answer 3

Docker is a software platform that you can use to build, test, and deploy applications quickly. Docker packages software into standardized units called containers that have everything the software needs to run, including libraries, system tools, code, and runtime. Using Docker, you can quickly deploy and scale applications into any environment and know that your code will run. By using containers, you decouple applications from operating systems.

Question 4

What is a Dockerfile?

Answer 4

Dockerfile is the file that is used to build the Docker image. It contains all the commands you would normally run manually in to build a Docker image.

Question 5

What is an image?

Answer 5

A Docker image is the file for Docker containers at runtime. It is an ordered collection of root filesystem changes and the corresponding parameters for use within a container runtime.

Question 6

What is a Docker Registry?

Answer 6

A Docker Registry stores Docker images, which can be public or private.

Question 7

What is a Docker container?

Answer 7

A Docker container is a runnable instance of an image.

Question 8

What is a Docker Host?

Answer 8

In this context, host is the machine (physical or virtual) that is running the host OS on which the Docker containers are run.

Question 9

Versions in Docker

Answer 9

• simplifies

Question 10

What are the challenges?

Answer 10

Managing a single container is easy
Managing a fleet is difficult
Solution: 
- Management - 12ECS, 34EKS
  - Deployment, scheduling, scaling and management of containerized applications
- Hosting - 13EC2, 24AWS Fargate
- Image registry - 1ECR