Shared storage is the solution. Caddy supports multiple different storage backends (filesystem by default, and Redis, Consul, DynamoDB via plugins) and uses the

Shared storage is the solution. Caddy supports multiple different storage backends (filesystem by default, and Redis, Consul, DynamoDB via plugins) and uses the storage to write locks so that one instance of Caddy can initiate the ACME order, and another can solve the challenge. See the docs: https://caddyserver.com/docs/automatic-https#storage https://caddyserver.com/docs/automatic-https#storage I'm doing this exact thing, with the Redis plugin behind DNSRR and it works seamlessly.