Bug 1375676

Summary: metrics: line not rendered on x-axis just before leaving 0 and after returning to 0
Product: OpenShift Container Platform Reporter: Mike Fiedler <mifiedle>
Component: Management ConsoleAssignee: Samuel Padgett <spadgett>
Status: CLOSED WONTFIX QA Contact: Yadan Pei <yapei>
Severity: low Docs Contact:
Priority: unspecified    
Version: 3.3.0CC: aos-bugs, jokerman, mifiedle, mmccomas, yanpzhan
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Hardware: x86_64   
OS: Linux   
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Last Closed: 2019-06-04 20:09:07 UTC Type: Bug
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Description Mike Fiedler 2016-09-13 16:25:38 UTC
Created attachment 1200562 [details]
Metrics

Description of problem:

There are breaks in the metrics graph just before and after a metric value changes from 0 to non-zero and then back again.


Version-Release number of selected component (if applicable): 3.3.0.30


How reproducible: Always


Steps to Reproduce:
1. Install OpenShift with metrics enabled
2. Create some hello-openshift pods
3. Periodically hit the pods with curl
4. View metrics for the pods

Actual results:

See attached image


Expected results:

It seems and unbroken line would be more correct.

Comment 1 Jessica Forrester 2016-09-13 16:45:21 UTC
This a known side effect of using splines, which otherwise look much better than  plain line graphs.

Comment 2 Samuel Padgett 2016-09-13 16:59:54 UTC
Some background from c3.js.

https://github.com/c3js/c3/issues/479
https://github.com/c3js/c3/issues/1608

We might be able to use a different interpolation option.

https://github.com/c3js/c3/pull/1268

Comment 3 Samuel Padgett 2016-09-13 18:16:09 UTC
Looked at this a bit. None of the out-of-the-box interpolation types prevent values dipping below 0. "monotone" helped in some cases, but not all. We'd need to write a custom interpolation function or go back to a line chart to fix this completely.

Comment 4 Samuel Padgett 2019-06-04 20:09:07 UTC
We've changed charting libraries in 4.1 to plotly, which does not have this issue. We do not plan to update the charts in the 3.x.