Security Hardening
Container security is about reducing the blast radius if an application is compromised. Docker containers share the host kernel, so without hardening an attacker who escapes a container gains access to everything.
Defense in Depth
flowchart TD
A["Application Code<br/>Secure dependencies, input validation"] --> B["Container Runtime<br/>Non-root, drop capabilities, read-only FS"]
B --> C["Image Supply Chain<br/>Minimal base, scan CVEs, pin digests"]
C --> D["Host & Network<br/>Firewall, private networks, log monitoring"]
style A fill:#e8f5e9,stroke:#2e7d32
style B fill:#e3f2fd,stroke:#1565c0
style C fill:#fff3e0,stroke:#ef6c00
style D fill:#f3e5f5,stroke:#7b1fa2
What You Will Learn
| Lesson | What It Covers |
|---|---|
| Container Security Basics | Non-root users, capabilities, read-only filesystems |
| Image Security | Minimal base images, vulnerability scanning, digest pinning |
| Secrets Management | File-based secrets, environment variable risks, Compose secrets |
| Security Audit Checklist | Actionable pre-deployment security review |
The Golden Rule
Every container should run with the minimum privileges needed to function. If it does not need root, do not give it root. If it does not need a capability, drop it.