Docker containerization in Express - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Docker containerization?

Docker containerization is a way to package an application and its environment into a small, portable unit called a container. This container runs the app consistently on any system with Docker installed.

beginner

Why use Docker containers for an Express app?

Using Docker containers for an Express app ensures the app runs the same everywhere. It packages the app, Node.js, and all dependencies together, avoiding "it works on my machine" problems.

beginner

What is a Dockerfile in Docker containerization?

A Dockerfile is a simple text file with instructions to build a Docker image. It tells Docker how to set up the environment, install dependencies, and run the Express app inside a container.

intermediate

How does Docker help with environment consistency?

Docker containers include everything the app needs, like code, libraries, and system tools. This means the app behaves the same on any computer, avoiding differences in setups or missing software.

beginner

What command starts a Docker container from an image?

The command is docker run. It creates and starts a container from a Docker image, running the Express app inside it.

What does a Docker container include?

A App code, dependencies, and environment

B Only app code

C Only system files

D Only the operating system

A Docker container packages the app code, its dependencies, and the environment needed to run it.

Which file defines how to build a Docker image?

A package.json

B Dockerfile

C docker-compose.yml

D README.md

The Dockerfile contains instructions to build a Docker image.

What command runs a Docker container?

A docker run

B docker build

C docker push

D docker pull

docker run starts a container from an image.

Why is Docker useful for Express apps?

A Replaces Node.js

B Makes the app run faster

C Ensures app runs the same everywhere

D Removes the need for coding

Docker ensures the Express app runs consistently on any system.

Which of these is NOT part of Docker containerization?

A Packaging app and environment

B Running app in isolated container

C Sharing app as an image

D Changing app source code automatically

Docker does not change app source code automatically; it packages and runs it.

Explain how Docker containerization helps solve the 'it works on my machine' problem for Express apps.

Think about how packaging everything together helps.

Describe the role of a Dockerfile when containerizing an Express app.

It's like a recipe for making the container.