This talk will cover the dynamic nature of cloud-based services, and how approaches that worked when everything had a dedicated machine no longer work out both technically and in terms of human operational effort. This includes the dynamic nature of cloud-based environments where there can be high churn due to releases potentially several times an hour, heterogeneous performance of replicas and complex micro-service dependency graphs. There will be a quick overview of the history of the TSDB of Prometheus, giving context to the new storage engine in the 2.0 release and how it helps with the above technical problems. Following that will be a look at service discovery to find what to monitor in dynamic environments, the aggregation abilities of PromQL and how these can be combined to perform symptom rather than cause based alerting using techniques such as the RED method.