Service level indicator question

[nghson]

Hi, as I understand, when there is SLI metric violation then we try to find the root cause for that violation. But in my case, circa gives scores for non-parent nodes of the SLI which are not responsible for the change in it. Moreover, changing SLI still gives the same result and scores. Could you please clarify this?

[limjcst]

It sounds like a known "feature".

CIRCA does score every node. The underlying philosophy is that we treat the root causes as a fault's observed projection in the space defined by monitoring metrics. Because the fault is an unobserved confounder of root cause metrics, there may be a monitoring metric that is not an ancestor of the SLI but indicates the fault directly, as if it is the fault's "side effect". A node's score is calculated based on the node itself and its parents. Hence, the change in any other nodes will not influence the score.

If you are a researcher, this can be an opportunity for you to extend the existing literature. One necessary step may be answering what kind of root causes operators need. If you are looking for a satisfying RCA tool, a simple solution is to prune the graph and reserve the SLI's ancestors.

[nghson]

Thanks for the answer. In the sample code data = CaseData(

circa.model.data_loader.MemoryDataLoader is derived from

# circa.model.data_loader.DataLoader, which manages data with configurations
data_loader=MemoryDataLoader(mock_data_with_time),
sli=latency,
detect_time=240,
lookup_window=4,
detect_window=2,

), if changing sli does not influence the score then what is the purpose of the param sli?

[limjcst]

I am afraid that I have abused the word CIRCA.

• As an RCA algorithm, CIRCA (specifically speaking, circa.alg.ci.RHTScorer combined with circa.alg.ci.DAScorer) does not rely on sli.
• As a package, the param sli is prepared for other RCA algorithms. For example,
  • MicroHECL will traverse the call graph, starting from the initial anomalous service, where the anomalous metric of the initial anomalous service will be the sli.
  • circa.alg.dfs.MicroHECLScorer is our corresponding implementation.

[nghson]

Ok, many thanks :D