Description

When running Sitecore container environments on Docker 29, the existing Traefik version (v2.11.0) is not compatible and may lead to Docker API communication errors. To resolve this, Traefik must be upgraded to a compatible version (v3.x).

After upgrading to Traefik v3.x, the environment may still return HTTP 404 responses if required service port labels are not configured. In this case, Traefik can detect the containers but fails to determine the backend service port, resulting in errors such as port is missing and failed routing.

To fully resolve the issue, explicit service port labels must be configured for the affected services.

Solution

1. Upgrade Traefik from v2.11.0 to v3.7.5 or later for compatibility with Docker 29.
2. Update the Traefik image in the .env file to match the container OS version:
   • For ltsc2022:
     TRAEFIK_IMAGE=traefik:v3.7.5-windowsservercore-ltsc2022
     
   • For ltsc2025:
     TRAEFIK_IMAGE=traefik:v3.7.5-windowsservercore-ltsc2025
3. Update the docker-compose.yml file to include explicit Traefik service port labels for the relevant Sitecore roles:
   • For ID:
     traefik.http.services.id-secure.loadbalancer.server.port=80
     
   • For CD:
     traefik.http.services.cd-secure.loadbalancer.server.port=80
     
   • For CM:
     traefik.http.services.cm-secure.loadbalancer.server.port=80
     

Note:

• This solution applies to container environments running on Windows Server 2022 and 2025.
• The Traefik image tag must match the container OS version in use.
• Windows Server 2019 containers are not supported, as they are limited to older Traefik versions that rely on outdated Docker API versions and are not compatible with Docker 29.
• Traefik v3.x images required for compatibility are only published for ltsc2022 and ltsc2025 (see Traefik Docker image tags).