Docker in production with Nginx — reverse proxy, TLS and hardening

Docker solves "works on my machine", but in production you need a controlled entry point: Nginx in front of the containers, with TLS terminated in one place, isolated networks and closed ports. A practical, step-by-step guide with docker-compose.

Why Docker + Nginx

• Isolation and reproducibility — each app with its own dependencies, identical on dev and prod.
• A single entry point — Nginx terminates TLS once and routes to containers by domain/path.
• Small attack surface — only 80/443 exposed; databases stay on the internal Docker network, no public port.
• Simple operations — restart policy, healthcheck, updates via image re-pull.

Architecture

The internet reaches only Nginx (80/443). Nginx proxies to the app containers over an internal Docker bridge network. The database is on the same network but publishes NO port to the outside.

Step 1 — Install Docker

• Install Docker Engine + the compose plugin (Debian/Ubuntu): packages docker-ce docker-ce-cli containerd.io docker-compose-plugin from the official Docker repo.
• Verify: docker run --rm hello-world and docker compose version.
• Create a dedicated network: docker network create web (user-defined network = DNS resolution between containers by name).

Step 2 — docker-compose for the app

Example docker-compose.yml with an app + Postgres, healthcheck and restart policy:

• services.app: image, restart: unless-stopped, expose: ["8080"] (NOT ports — do not publish), networks: [web], healthcheck with test: curl -f http://localhost:8080/health.
• services.db: image: postgres:16, volumes: [dbdata:/var/lib/postgresql/data], networks: [web], NO ports — reachable only internally.
• Secrets (passwords) via environment from a .env file (not baked into the image), or secrets.
• Start: docker compose up -d; check: docker compose ps, docker compose logs -f app.

Step 3 — Nginx reverse proxy

Nginx (on the host or as a container on the same web network) proxies to the container by service name:

• upstream or proxy_pass http://app:8080; (the name "app" resolves via the Docker network DNS).
• Correct headers: proxy_set_header Host $host; X-Real-IP $remote_addr; X-Forwarded-For $proxy_add_x_forwarded_for; X-Forwarded-Proto $scheme;
• WebSocket (if needed): proxy_http_version 1.1; + Upgrade / Connection.
• Multi-app routing: by server_name (different domains) or location /app2/ to proxy_pass http://app2:3000;.

Step 4 — TLS with Let's Encrypt

• Redirect 80 -> 443 for all human traffic; leave only /.well-known/acme-challenge/ open on 80.
• Certificate: certbot --webroot (or a certbot container in compose) with automatic renewal.
• In the 443 block: ssl_certificate / ssl_certificate_key, ssl_protocols TLSv1.2 TLSv1.3.

Step 5 — Hardening

• No needless ports: only Nginx publishes 80/443. DB and app use expose, not ports.
• Non-root in the container: user: in compose or USER in the Dockerfile; avoid running as root.
• Read-only + no-new-privileges: read_only: true, security_opt: [no-new-privileges:true], cap_drop: [ALL].
• Resource limits: deploy.resources.limits (CPU/RAM) so one container cannot take down the host.
• Security headers at Nginx: HSTS, X-Content-Type-Options, X-Frame-Options, Referrer-Policy, CSP.
• Small images + updates: -slim/alpine bases, scan with docker scout / Trivy, re-pull regularly.

Automatic Let's Encrypt

The certificate should not be renewed by hand. Certbot installs a systemd timer (certbot.timer) that runs certbot renew twice a day and only renews what expires in under 30 days.

• Reload nginx after renewal: certbot renew --deploy-hook "nginx -s reload".
• Test without real issuance: certbot renew --dry-run.
• In Docker: either a certbot container with a volume shared with nginx (renew loop), or the nginx-proxy + acme-companion pattern that issues and renews certificates per container automatically, based on the VIRTUAL_HOST / LETSENCRYPT_HOST variables.

GeoIP + nftables firewall

Country blocking can happen at two levels. At the nginx level (GeoIP2 module + map $geoip2_country_code) you reply with 403. It is more efficient to drop packets in nftables before they reach nginx — that also blocks scans, not just HTTP requests.

• Put country prefixes into an nftables set (interval): set blocked_cc { type ipv4_addr; flags interval; }.
• Rule in the input chain: ip saddr @blocked_cc drop (or the inverse whitelist: accept only allowed countries).
• Prefix source: per-country lists (e.g. ipdeny.com) or a GeoIP database; a cron script reloads the set daily.
• Persist in /etc/nftables.conf; check with nft list ruleset.
• Blacklist vs whitelist: blacklist (block a few high-risk countries) is safe; whitelist (only your country + a few) is aggressive — it may block legitimate bots/CDNs, so test first.

CrowdSec on Nginx logs

CrowdSec reads the nginx logs (access.log / error.log), applies scenarios and blocks hostile IPs — with collective intelligence (IPs reported across the whole CrowdSec network).

• Acquisition: in /etc/crowdsec/acquis.yaml add the nginx log paths (type nginx).
• Collections: cscli collections install crowdsecurity/nginx crowdsecurity/base-http-scenarios crowdsecurity/http-cve — detects brute-force, path scanning, flood, malicious user-agents, exploit attempts.
• Bouncer (enforces the block): crowdsec-firewall-bouncer puts IPs into an nftables set (crowdsec-blacklists) → drop; or crowdsec-nginx-bouncer which replies 403 at the nginx level.
• Operations: cscli decisions list, cscli metrics, cscli alerts list; enroll in the CrowdSec console for a dashboard + community blocklists (CTI).
• vs fail2ban: CrowdSec has richer scenarios and collaborative reputation; fail2ban is still fine for simple, local rules.

Logging and operations

• Logs: docker compose logs; for production, the json-file driver with max-size/max-file or ship to a log stack (Loki).
• App update: docker compose pull && docker compose up -d (recreates only what changed).
• Backup: the volumes (dbdata) — docker run --rm -v dbdata:/data ... or a scheduled pg_dump.
• Health: docker compose ps shows healthcheck status; the restart policy brings a crashed container back.

Conclusion

The Nginx + Docker pattern gives you reproducible deploys, a single TLS entry point and a minimal attack surface — from a single VPS to multiple nodes. We design it, secure it and monitor it for you.