User Request: Support for percentage in CPU stress about chaos-controller HOT 3 CLOSED

Hi Nikos, sorry for the late reply, we didn't link this issue in the related PR but the feature is now available (for a few versions actually).

from chaos-controller.

Hi Nikos, we have such a thing in our backlog with no ETA at the moment though we didn't plan to support a specific percentage, more a number of cores (that could be specified as a percentage per say but that would be rounded depending on the number of cores). A concrete example would be that specifying something like

spec:
  cpuPressure:
    pct: 40%

would result in using half of the cores at 100% (so in reality 50%). The reason is that it we can easily eat all allocated cores (and we can also easily decide how many cores we want to allocate to the injector process) but we can't easily precisely compute a percentage of CPU usage within the injector itself.

Another spec format could be:

spec:
  cpuPressure:
    cores: 2

But then it is less dynamic depending on the target since we have a fix number of cores.

Would it fit your needs or did you think about using a specific percentage of CPUs?

from chaos-controller.

Thanks Joris.

Got it, it gets tricky due to its implementation.

I think a percentage would be more user-friendly, but if it is not deterministic it may confuse the users.

Do you know how tools like stress-ng achieve that? It seems to support number of workers (cores) and load (percentage).

from chaos-controller.