*Range Vectors cannot be used as operands. You must aggregate them back to Instant Vectors using a built-in _function_.
7⃣ Vector matching
vector <op> vector is a tricky one!
Since vectors are on both sides, a by-element matching is required to perform such operations.
The actual matching rules depend on the type of the operation - arithmetic, comparison, or set operation.
Cheatsheet 🔽
8⃣ Hands-on learning
The best way to learn Prometheus and PromQL is by trying to feed a Prometheus node with some well-known dataset, issuing queries to it, and analyzing the results.
I often search for container images, and here is my pain:
- There is more than one place to go - Docker Hub, GCR, Quay
- Some software has multiple image providers - e.g Envoy
- Image trustworthiness and difference are obscure