Let's Encrypt

Overview

Traefik can automatically generate and renew TLS certificates using an ACME provider, such as Let’s Encrypt. This simplifies certificate management while ensuring secure HTTPS connections.

Let’s Encrypt and Rate Limiting

Let’s Encrypt imposes rate limits for API requests, which last up to one week and cannot be overridden. To avoid reaching these limits:

• Persist the acme.json file across container restarts to prevent Traefik from requesting new certificates unnecessarily.
• Use the Let’s Encrypt staging server with the caServer configuration option for testing.

 

Certificate Resolvers

Certificate resolvers are defined in the static configuration and retrieve certificates from an ACME server. Each router that requires a certificate must reference a resolver explicitly using the tls.certresolver option.

Configuration Reference

• Domain Definition: Certificates are requested for domain names specified in the router’s dynamic configuration. Multiple domain names are supported, with one acting as the main domain and others as Subject Alternative Names (SANs).
• ACME Challenges: Each resolver must define an ACME challenge type: HTTP-01, DNS-01, or TLS-ALPN-01.

 

Configuration Examples

Enable ACME

# Static configuration
dentryPoints:
  web:
    address: ":80"

  websecure:
    address: ":443"

certificatesResolvers:
  myresolver:
    acme:
      email: [email protected]
      storage: acme.json
      httpChallenge:
        entryPoint: web

Single Domain from Router’s Rule

# Dynamic configuration
labels:
  - traefik.http.routers.blog.rule=Host(`example.com`) && Path(`/blog`)
  - traefik.http.routers.blog.tls=true
  - traefik.http.routers.blog.tls.certresolver=myresolver

Multiple Domains from Router’s Rule

# Dynamic configuration
labels:
  - traefik.http.routers.blog.rule=(Host(`example.com`) && Path(`/blog`)) || Host(`blog.example.org`)
  - traefik.http.routers.blog.tls=true
  - traefik.http.routers.blog.tls.certresolver=myresolver

Multiple Domains from Router’s tls.domain

# Dynamic configuration
labels:
  - traefik.http.routers.blog.rule=Host(`example.com`) && Path(`/blog`)
  - traefik.http.routers.blog.tls=true
  - traefik.http.routers.blog.tls.certresolver=myresolver
  - traefik.http.routers.blog.tls.domains[0].main=example.com
  - traefik.http.routers.blog.tls.domains[0].sans=*.example.org

 

ACME Challenges

HTTP-01 Challenge

# Static configuration
entryPoints:
  web:
    address: ":80"
  websecure:
    address: ":443"

certificatesResolvers:
  myresolver:
    acme:
      httpChallenge:
        entryPoint: web

DNS-01 Challenge

# Static configuration
certificatesResolvers:
  myresolver:
    acme:
      dnsChallenge:
        provider: digitalocean
        delayBeforeCheck: 0
        resolvers:
          - "1.1.1.1:53"
          - "8.8.8.8:53"

TLS-ALPN-01 Challenge

# Static configuration
certificatesResolvers:
  myresolver:
    acme:
      tlsChallenge: {}

 

Automatic Renewals

Traefik manages 90-day certificates and renews them automatically 30 days before expiry. For resolvers issuing custom-duration certificates, configure the renewal duration with the certificatesDuration option.

For more details, refer to the official Traefik documentation.