A Dockerfile 🐬 is a text-based document that provides instructions for creating a container image. Let's walk through the basics of writing one:

1. Choose a Base Image:
Start by specifying the base image you want to use. It serves as the foundation for your custom image. For example:
FROM node:14

2. Set the Working Directory:
Use the WORKDIR instruction to define the working directory inside the container:
WORKDIR /usr/src/app

3. Copy Files:
Use COPY or ADD to copy files from your local machine into the image:
COPY package\.json package-lock\.json \./

4. Install Dependencies:
Run any necessary commands to install dependencies (e.g., using RUN npm install for Node.js):
RUN npm install

5. Expose Ports:
Specify which ports your application will listen on using EXPOSE:
EXPOSE 3000

6. Define Startup Command:
Finally, set the command that runs when the container starts:
CMD ["npm", "start"]

Remember, this is just a basic example. You can customize your Dockerfile based on your specific application and requirements.

For a hands-on tutorial, check out this Dockerfile tutorial from Docker's official documentation. [1]

➡️Reference links: [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14]


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