FYI, I was hired by Gravitational back in April 2018 and I was given that same take-home assignment as part of the interview process - to write a CNI plugin for k8s which created an encrypted mesh network between nodes. My work is here: https://github.com/webvictim/k8s-ipsec-cni
I found some other resources/projects online while I was writing this which indicated that I certainly wasn't the first interviewee to be asked to do this - I evidently wasn't the last either as your project shows.
My point is that it seems Gravitational has had this 'idea' for quite some time as they've been using it as an interview question for at least the year 2018. I don't feel like that constitutes them using anyone's interview work as free labour.
I found some other resources/projects online while I was writing this which indicated that I certainly wasn't the first interviewee to be asked to do this - I evidently wasn't the last either as your project shows.
My point is that it seems Gravitational has had this 'idea' for quite some time as they've been using it as an interview question for at least the year 2018. I don't feel like that constitutes them using anyone's interview work as free labour.