How to Securely Manage Secrets in Docker

Read the full article here: https://blog.gitguardian.com/how-to-handle-secrets-in-docker/?soure=nhimg

Managing secrets in Docker can make or break your container security. From leaked API keys to hardcoded passwords, mishandled secrets can expose your infrastructure to serious risks.

In this guide, we’ll walk through four proven ways to manage secrets in Docker—and help you avoid common pitfalls like storing sensitive data in plaintext or baking it into your Dockerfiles.

1. Use Docker Secrets with Docker Swarm

Docker Secrets lets you securely store sensitive data and makes it available only to containers that need it. When combined with Docker Swarm, it gives you encrypted secret handling and access control at scale.

2. Docker Compose with External Secret Files

If you’re not using Swarm, Docker Compose still lets you inject secrets using local files.

3. Use Sidecar Containers (e.g., with HashiCorp Vault)

A powerful pattern is using a sidecar container that handles secrets (like Vault), and shares them securely with your main app container via a mounted volume.

This separates secret management from the application logic, and can be automated using tools like Kubernetes or CI/CD.

4. Mozilla SOPS

If you need to decrypt secrets locally before passing them to Docker (especially in development), Mozilla SOPS is your friend.

Scan Docker Images for Leaked Secrets

Even if your Dockerfiles are clean, your base image might not be.

Scan every image you build using tools like ggshield (GitGuardian CLI) to catch hardcoded secrets across layers—before they go to production.