We are using Traefik as reverse proxy, with a Traefik instance on each of our 3 proxy servers, orchestrated by Docker Swarm. We would like to start using LetsEncrypt TLS/SSL certificates for some admin domains, but have trouble with the verification and certificate distribution among those instances.
Docker Swarm volume and secret can not be updated from within a container, and for concurrency reasons you should not share the acme.json file across multiple instances of Traefik.
So how do you make LetsEncrypt work with multiple Traefik instances on Docker Swarm?