プロキシありで、Discourseインスタンスをもう一つ作成する設定はうまくいきますか？

[pfaffman (Jay Pfaffman)]

Also, it’s probably better to use a two container setup to have just one database, but you need two redis. You could also consider multisite.

Multisite configuration with Docker

Setup Multisite Configuration with Let’s Encrypt and no Reverse Proxy