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Avoid These Common Mistakes in Docker and Follow These Amazing Best Practices
For non-members, read this article for free on my blog: Top 10 Common Mistakes in Docker and How to Avoid Them.
Docker has revolutionized the way we build, ship, and deploy applications. However, many developers and DevOps engineers unknowingly make mistakes that lead to performance issues, security vulnerabilities, and broken deployments. In this guide, we’ll explore the 10 most common Docker mistakes and how to fix them. Let’s dive in! 🚀
🔴 1️⃣ Running Containers as Root
❌ Mistake: Running Containers with Root Privileges
By default, Docker containers run as the root user, which is a major security risk.
# BAD: Running as root (default behavior)
FROM node:18
WORKDIR /app
COPY . .
CMD ["node", "server.js"]✅ Best Practice: Use a Non-Root User
Create a dedicated user inside the container to improve security.
# GOOD: Running as non-root user
FROM node:18
WORKDIR /app
COPY . .
RUN useradd -m appuser && chown -R appuser /app
USER appuser
CMD ["node", "server.js"]🔹 Fix: Always run containers with a non-root user to reduce security risks.
🔴 2️⃣ Using latest Tag for Images
❌ Mistake: Pulling the latest Image Version
Using the latest tag doesn't guarantee a stable version, leading to unexpected updates.
docker pull node:latest # ❌ BAD - Unpredictable updates✅ Best Practice: Pin Image Versions
Specify exact image versions to ensure stability.
docker pull node:18.16.0 # ✅ GOOD - Stable and predictable🔹 Fix: Always pin image versions instead of using latest.
🔴 3️⃣ Ignoring .dockerignore File
❌ Mistake: Copying Unnecessary Files into the Container
If you don’t use a .dockerignore file, unnecessary files like .git, node_modules, and logs bloat the image.
# BAD: Copies everything, including unnecessary files
COPY . /app
