My Docker Cheat Sheet: A Newbie’s Toolkit

Simple Docker Commands for Everyday Development on a MacBook M2

Hey everyone! I’m pretty new to the whole Docker scene and I’ve been hacking around with it to develop a container for Juno devs. I thought I’d share some commands that I’ve found helpful along the way. They’re easy to follow and have been a great aid to me, a self-proclaimed newbie in this domain.

Dockerfile

Before we delve into the Docker commands, let’s begin with a basic Dockerfile as an example, such as the following for a basic Node.js application:

# Use the official Node.js 18 Alpine image as a base
FROM node:18-alpine

# Set the working directory inside the container
WORKDIR /app

# Copy the package.json and package-lock.json
COPY package*.json ./

# Install production dependencies
RUN npm ci

# Copy the application source code
COPY . .

# Command to run the application
CMD ["node", "src/index.js"]

# Expose port 3000
EXPOSE 3000

A Dockerfile is a blueprint for building Docker images. It contains the commands that are executed when the image is assembled with docker build. This command does not start the container. Instead, it reads the Dockerfile and executes the instructions within it, resulting in a Docker image. This image contains everything needed to run your application - the base operating system, application code, dependencies, environment variables, and other configurations.

On the contrary, docker run will start a container from that image. This is when your application actually starts running. docker run takes the image created by docker build and starts a container from it. You can start, stop, and restart this container without having to rebuild the image, unless there are changes to the Dockerfile or the context that require a new image to be built.

Now, Let’s Explore the Docker Commands…

Building Your Image

When you’re just getting started, the first step is to build your Docker image. Here’s the command I typically use:

docker build . --file Dockerfile -t my-project --platform=linux/amd64