Docker Container Guide: Run, Build, and Deploy Faster

If you’ve landed here, you probably want to get comfortable with containers without drowning in documentation. This Docker Container Guide walks you from basic concepts to practical workflows — images, Dockerfile tips, Compose, and a bit on Kubernetes — with real examples and clear next steps. I’ll share what I’ve learned from building and shipping apps: the shortcuts that save time, the pitfalls that trip teams up, and the commands you’ll use every day.

What is a Docker container (and why it matters)

Containers package an application with its dependencies so it runs the same anywhere. Unlike virtual machines, containers share the host OS kernel. That makes them lightweight, fast, and portable. If you want the formal background, see the history of containerization on Wikipedia.

When to use containers

• Microservices: isolate services for independent deployment.
• Local dev parity: run the stack the same as CI and production.
• CI pipelines: build, test, and publish reproducible images.

Docker basics: images, containers, and Dockerfile

Three terms you’ll use constantly: image (immutable snapshot), container (running instance), and Dockerfile (instructions to build an image). Images are layered — changes sit on top of a base image. That layering is why small, focused images matter.

Minimal Dockerfile example

Here’s a tiny Node.js Dockerfile pattern I use a lot to keep images lean:

FROM node:18-alpine
WORKDIR /app
COPY package*.json ./
RUN npm ci –only=production
COPY . .
CMD [“node”,”index.js”]

Tip: Use alpine or slim variants for smaller images; separate dependency install steps to leverage build cache.

Common Docker commands you’ll actually run

• docker build -t myapp:latest . — build an image
• docker run -d -p 8080:80 –name myapp myapp:latest — start a container
• docker ps — list running containers
• docker logs -f myapp — stream logs
• docker exec -it myapp /bin/sh — inspect container shell

Docker Compose: orchestrating local multi-container apps

Compose is the easiest way to define multi-container apps (web + db + cache). Use a docker-compose.yml to declare services, networks, and volumes. The official docs have practical examples and best practices at Docker Compose documentation.

Example docker-compose.yml

version: ‘3.8’
services:
web:
build: .
ports:
– “8080:80”
depends_on:
– db
db:
image: postgres:15-alpine
environment:
POSTGRES_PASSWORD: example

Containers vs Virtual Machines: quick comparison

Short table to clear the fog. This matters when you plan infrastructure or migrations.

Building production-ready images and security

From what I’ve seen, teams rush to CI/CD without considering image security and size. Two small habits reduce risk: minimize the attack surface and scan images regularly.

Best practices

• Use minimal base images (alpine, distroless).
• Run as non-root user inside the container.
• Remove build tools in multi-stage builds.
• Scan images with tools like Trivy or Clair in CI.

Multi-stage build snippet

# build stage
FROM golang:1.20-alpine AS builder
WORKDIR /src
COPY . .
RUN go build -o /app/myapp

# final stage
FROM alpine:3.18
COPY –from=builder /app/myapp /usr/local/bin/myapp
USER 1000
CMD [“/usr/local/bin/myapp”]

Deploying containers: quick paths

There are three approachable paths depending on scale:

• Single host — docker run + systemd or restart policies for small services.
• Docker Swarm / Compose on Swarm — built-in clustering, simpler than Kubernetes.
• Kubernetes — for complex, highly-available production systems. If you need an entry point to Kubernetes concepts, the Cloud Native Computing Foundation offers valuable resources at CNCF.

Real-world example: staging deployment

I once used a tiny CI pipeline: build image, push to registry, and remote-run a rolling update on a small cluster with Compose and a simple healthcheck. It’s not fancy, but it cut deployment time from 30 minutes to under 5.

Performance and storage tips

• Prefer read-only layers and bind-mounts for development only.
• Clean up unused images with docker image prune.
• Use image registries with geo-replication for global teams.

Troubleshooting checklist

If a container misbehaves, try these quick checks:

• Check logs: docker logs -f.
• Inspect container state: docker inspect.
• Run lightweight debugging shell: docker exec -it.
• Verify image layers and rebuild without cache if necessary.

Next steps and learning path

Start small: containerize a single app, add Compose, then look at CI integration. Once you’re comfortable, try migrating a staging app to Kubernetes. The official Docker site has walkthroughs and tutorials that are handy when you need step-by-step guides: Docker Docs.

Further reading and trusted references

• Docker: Get Started guide — hands-on tutorials
• Containerization (Wikipedia) — history and context
• CNCF — cloud native ecosystem resources

Final nudge: pick a small app, write a Dockerfile, and run it locally. You’ll learn more in an afternoon than reading a week of docs. If you want, I can provide a tailored Dockerfile for your stack.