1. When should you consider sharding Prometheus?
2. What's the difference between sharding vertically and horizontally?
3. Is there anything you can do before opting for a sharding strategy?
4. What type of metrics are best suited for being federated in a hierarchical pattern?
5. Why might you require cross-service federation?
6. What protocol is used between Thanos querier and sidecar?
7. If a replica label is not set in a Thanos querier that is configured with sidecars running alongside Prometheus HA pairs, what happens to the results of queries that are executed there?