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HTTPS and TLS

Updated Feb 05, 2023 ·

Overview​

To secure your app with HTTPS, Traefik lets you use different types of TLS certificates.

  • Let Traefik auto-generate, if no cert is given (not trusted)
  • Use your own (manual)
  • Let’s Encrypt (automated and trusted)

This keeps your app safe with HTTPS, whether you set up the certificates yourself or let Traefik manage them.

  • TLS settings can go in static or dynamic config
  • If Let’s Encrypt is used, Traefik creates and renew certs for you
info

Let’s Encrypt is usually the best choice if you want easy, secure, and automated certificate management.

Self-Signed Certificates​

If you don’t provide any certificate, Traefik will create a self-signed one.

  • Automatically generated by Traefik
  • Browser shows warning that it's not trusted

This is useful for testing, but not recommended for production.

User-Defined Certificates​

You can provide your own certificates if needed.

  • Upload your cert and key files to Traefik
  • Define their path in the configuration
  • You can set more fine-grained configurations
  • Traefik matches them to the correct entry points

You’re responsible for renewing these certificates before they expire.

Sample Configuration (User-defined certificate):

tls:
  certificates:
    - certFile: "/certs/domain.crt"
      keyFile: "/certs/domain.key"
    - certFile: "/certs/another-domain.crt"
      keyFile: "/certs/another-domain.key"

Once mounted, Traefik will handle the rest automatically.

Let’s Encrypt with Traefik​

Let’s Encrypt lets Traefik create and renew certs for you automatically.

  • No need to manually manage cert files
  • Works well for testing and general use
  • Certificates are renewed automatically before they expire

This is the easiest option when you don’t have strict company requirements.

Types of Let’s Encrypt Challenges​

Traefik supports different methods to prove domain ownership.

  • HTTP Challenge

    • A temporary URL is created for verification

    • Let’s Encrypt gives a token to Traefik

    • Token is then served back to Let’s Encrypt for verification

      http://<YOUR_DOMAIN>/.well-known/acme-challenge/<TOKEN>

  • DNS Challenge

    • A DNS TXT record is created using your DNS provider
    • Let’s Encrypt looks at the record to verify ownership
    • Works with wildcard certificates

  • TLS Challenge

    • Performs a handshake between Traefik and Let’s Encrypt
    • Uses port 443 and handles everything at the TLS level

Here’s how the HTTP Challenge works:

[certificatesResolvers.myresolver.acme]
  email = "admin@example.com"
  storage = "acme.json"
  [certificatesResolvers.myresolver.acme.httpChallenge]
    entryPoint = "web"

DNS challenges work similarly but require access to your DNS provider’s API.

Matching Certificates to Entry Points​

Traefik automatically links the certificate to the right port and domain.

  • Port 443 is usually mapped to websecure
  • Traefik uses the domain to choose the correct certificate

Once matched, your website will show the secure lock icon in the browser.

Configuring TLS in Routers​

You also need to tell Traefik when to use TLS in your router.

labels:
  - "traefik.http.routers.myapp.tls=true"
  - "traefik.http.routers.myapp.entrypoints=websecure"
  - "traefik.http.routers.myapp.tls.certresolver=myresolver"

This enables TLS and tells Traefik to use Let’s Encrypt with your selected method.

Static versus Dynamic Config​

You can add your TLS settings to either config type.

  • Static config requires a restart to update
  • Dynamic config lets you reload without restarting

If you change certs often, use dynamic config for easier updates.

Clone the Repository​

To try out the examples, clone the project repository from GitHub.

Clone and move into the project directory:

git clone https://github.com/joseeden/labs-traefik.git 
cd labs-traefik/04-https-tls

Project structure:

Lab: Enabling Encryption (HTTPS)​

Cleanup​

To remove the resources:

docker compose -f <CONFIG_FILE_PATH> down

To check all stacks in your Swarm:

docker stack ls

To remove the specific stack:

docker stack rm <STACK_NAME>

To remove all stacks currently deployed in your Swarm:

docker stack ls --format '{{.Name}}' | xargs -r docker stack rm