StressChaos Experiment

This document helps you create StressChaos experiments.

StressChaos can generate plenty of stresses over a collection of pods. The stressors is injected into the target pods via the chaos-daemon internally.

Configuration

A StressChaos shares common configurations like other chaos, such as how to select pods, how to specify periodic chaos. You can refer to other docs for details. It defines stressors in either of the following two ways:

• stressors

  Stressors defines a plenty of stressors supported to stress system components out. You can use one or more of them to make up various kinds of stresses. At least one of the stressors should be specified. The following is supported stressors for now:

  1. memory

     A memory stressor will continuously stress virtual memory out.

     Option	Type	Required	Description
     workers	Integer	True	Specifies concurrent stressing instance.
     size	String	False	Specifies memory size consumed per worker, default is the total available memory. One can also specify the size as % of total available memory or in units of B, KB/KiB, MB/MiB, GB/GiB, TB/TiB.

  2. cpu

     A cpu stressor will continuously stress CPU out.

     Option	Type	Required	Description
     workers	Integer	True	Specifies concurrent stressing instance. Actually it specifies how many CPUs to stress when it’s less than available CPUs.
     load	Integer	False	Specifies percent loading per worker. 0 is effectively a sleep (no load) and 100 is full loading.

• stressngStressors

  StressngStressors defines a plenty of stressors just like Stressors except that it’s an experimental feature and more powerful.

  You can define stressors in stress-ng (see also man stress-ng) dialect.

  Note:

  However, not all of the supported stressors are well tested. It might be retired in later releases. Therefore, it is recommended to use Stressors to define the stressors and use this only when you want more stressors unsupported by Stressors.

  When both StressngStressors and Stressors are defined, StressngStressors wins.

Usage

Below is an example YAML file of StressChaos which is set to burn 1 CPU for 30 seconds in every 2 minutes:

apiVersion: chaos-mesh.org/v1alpha1
kind: StressChaos
metadata:
  name: burn-cpu
  namespace: chaos-testing
spec:
  mode: one
  selector:
    namespaces:
      - tidb-cluster-demo
  stressors:
    cpu:
      workers: 1
  duration: '30s'
  scheduler:
    cron: '@every 2m'

1. Create a namespace for your application. For example, tidb-cluster-demo:

   kubectl create ns tidb-cluster-demo

2. Create your pods in the target namespace:

   kubectl apply -f *your-pods.yaml*

3. Inject a StressChaos:

   kubectl apply -f *your-stress-chaos.yaml*

Then, your pod’s CPU will burn for 30 seconds.