Prometheus author here (Julius). Generally agreed that you can get far with a single Prometheus server (or many independent vanilla Prometheus servers, potenti

Prometheus author here (Julius). Generally agreed that you can get far with a single Prometheus server (or many independent vanilla Prometheus servers, potentially also using Prometheus's own federation). But I still recommend Thanos as an extension to a lot of people. I like Thanos because it's so easy to deploy alongside an existing Prometheus installation, while itself being mostly stateless (long-term state is kept in object storage), and it gives people: - a global view over multiple Prometheus servers - deduplicated view over servers in an HA pair - durable long-term storage for little cost The Thanos architecture diagrams (especially the one in their README.md) can look a bit intimidating, but I find it sooo easy to get started with in practice, since you don't even need to deploy all of the components to begin with it. I usually tell people to just drop in a Thanos sidecar next to each of their Prometheus servers, so they will get backups of all their Prometheus server data (for those who are interested in long-term data retention). And then later, they can add the Querier component for an integrated view over multiple servers. And then later they can deploy the Store gateway to also integrate back long-term data into that view. And then at some point, the compactor... Without being a Thanos expert, it took me ~15 minutes to deploy all those components (+ Minio for object storage) in front of a training audience that wanted to know more about Thanos (while reading Thanos + Minio docs). Of course a proper production deployment always takes way more time, but still I like how conceptually simple it is to integrate Thanos with Prometheus.