@gabor oh wow. If I spin a new Jekyll site, it takes me 10 mins to get going. If simplicity is the key for you here, adding Docker to the equation seems like adding unnecessary complication?
If you add the sitemap plugin to Jekyll, you don't need to worry about it - it's done for you during build.
Fosstodon is an English speaking Mastodon instance that is open to anyone who is interested in technology; particularly free & open source software.