Really great project. Instead of a fragile centralized approach Thanos embraced the federated nature of Prometheus. We see us using this for GitLab.com. I just discussed Thanos with Ben who works on the Prometheus project itself and who leads monitoring for GitLab: https://youtu.be/JzlwwGZ3yQ4
My interpretation is that Thanos is for massive scale, perhaps suitable for gitlab but most organisations would manage with just prometheus to start with and might scale up to thanos later.
Either that or just use basic Thanos setup (as described in a blog post) that gives you better Prometheus HA support and global view. You can always add setup for long-term metric retention later on.
