I currently use traefik as my reverse proxy in my homelab. It sits between my firewall and every service that I expose publicly. I have it running in docker and use docker compose to run the container and to define some traefik configuration. While this is not an overview of how to use traefik in docker, this is how you can add multiple domains to your traefik configuration with two or more wildcard certificates.
These are two of the labels defined in the docker compose file that specify your domain to create a wildcard cert to be used later.
- "traefik.http.routers.traefik-secure.tls.domains[0].main=exampledomain.com"
- "traefik.http.routers.traefik-secure.tls.domains[0].sans=*.exampledomain.com"But what if you want more than one domain? To use multiple domains with traefik in docker, you need to add a few more lines to this configuration. While it may not be completly clear, domains is actually an array. So its pretty simple to add more domains. We just need to duplicate those two lines and change the number in the brackets to 1, and then set the main and sans to your new domain.
- "traefik.http.routers.traefik-secure.tls.domains[0].main=exampledomain.com"
- "traefik.http.routers.traefik-secure.tls.domains[0].sans=*.exampledomain.com"
- "traefik.http.routers.traefik-secure.tls.domains[1].main=anoutherdomain.com"
- "traefik.http.routers.traefik-secure.tls.domains[1].sans=*.anoutherdomain.com"That's it. After restarting traefik, a new wildcard cert will be created and your new domain that we added to the array should now be available to use.