Don’t Ship Bloated Container Images

Hey there,

If you’ve ever said, “It works on my machine,” and then watched your app break in production, Docker was built to fix that.

It’s been nearly a decade since containerization went mainstream, yet teams still run into preventable deployment issues simply because the fundamentals get overlooked or forgotten.

In Today’s Issue:

→ A fast refresher on building, tagging, and pushing images that don’t break in prod.
→ A few best practices that still hold up

Let’s dive in.

The Core Docker Workflow

Containerization remains the fastest way to package your app and run it consistently across machines, clouds, or teams. It isolates dependencies, minimizes drift, and makes rollbacks and rebuilds predictable. All without needing to virtualize an entire OS.

It also underpins most CI/CD setups, supports microservice scaling, and cuts down provisioning time.

Image → Container: The Core of it

• Image: Your application blueprint, dependencies, config, code, environment.

• Container: A live, running instance created from that image

You build an image once, push it to Docker Hub (or a private registry), and spin up containers from it wherever you need them.

From Dockerfile to Deployment

To get Docker’s full benefits, your build process needs to be clean, versioned, and pushable.

Here’s a minimal Dockerfile for a Node.js app:

FROM node:24

WORKDIR /usr/src/app

COPY package*.json ./

RUN npm install

COPY . .

EXPOSE 8080

CMD ["node", "app.js"]

Build the image:

docker build -t my-node-app .

Run the Container:

docker run -p 8080:8080 my-node-app

Tag & Pushing to Docker Hub

Tag while building

docker build -t my-username/my-node-app:1.0 .

Or tag it afterward:

docker tag my-node-app:latest my-username/my-node-app:1.0

Log in:

docker login

Push the image:

docker push my-username/my-node-app:1.0
docker push my-username/my-node-app:latest

Once your workflow is solid, small improvements can have a big impact. Here’s how to get the most out of your Docker setup.

A few best practices that still hold up:

• Use .dockerignore : Exclude unnecessary files and speed up builds.

• Minimize layers: Combine RUN, COPY, and ADD where possible.

• Take advantage of caching: Place rarely changed instructions (like base image and dependencies) at the top.

• Use multistage builds: To reduce final image size, build artifacts in one stage, then copy only what you need into a lightweight base image.

• Pick smaller base images: Use options like (node:24-alpine) to trim megabytes off your builds.

• Tag with purpose: Use tags like (1.0, 2.0-alpha, etc.) and prune unused images from your registry.

• Automate it: Integrate Docker build, tag, and push into your CI/CD pipeline. No more manual pushes on Friday evenings.

These tweaks can shave hundreds of megabytes (MB) off your image and reduce cold start time.
Read the full guide to be well-grounded in building and pushing Docker images to Docker Hub→ here. 

What Keeps Docker in Every Pipeline

DevOps is all about repeatability, reliability, and speed. A clean, versioned image in Docker Hub means:

• Reduced build times

• More stable deploys

• Easier rollback and testing

• Happier developers

The basics aren’t old news; they’re the foundation of every smooth deployment. Skip them, and you ship chaos instead of code.