yet more downvotes, with no reasoning, on a relevant comment. hacker news is like that significant other that abuses you and you keep going back to. i can't keep making excuses for you hacker news.
FoundationDB was closed source, they just allowed to use their product for free in small deployments.
By the way, if you did not see it there was an update posted that states that FDB was closed source. It also doesn't matter that some components were open source or not, because without FDB they are useless either way.