Did you start to investigate that topic?
mongo:
https://www.mongodb.com/licensing/server-side-public-license
I mean, this looks really good for us And we could say to the world, if you use libre.sh and declarative open source infrastructure, you are covered!
redis:
This looks a bit more crazy… So even ecobytes would be screwed I guess. Do you know what are the plans? Is there a fork with pre-license change binaries?
[edit] actually on redis side, it looks good also: http://antirez.com/news/120
So basically, if you just use core, you should be fine. And I think it is what most open source projects use.