If I were running fastly, I'd donate bandwidth so that you would implement turn-key, bring-your-api-key fastly support to your open source setup!
As for other cdns - I remember https://neocities.org/ built their own cdn - but I couldn't immediately find a blog post about the cdn, or something related in their GitHub (unless every node runs part of it, which would make sense, I guess).
As for other cdns - I remember https://neocities.org/ built their own cdn - but I couldn't immediately find a blog post about the cdn, or something related in their GitHub (unless every node runs part of it, which would make sense, I guess).