Windows CPU stress

Windows CPU stress applies stress on the CPU resources of Windows OS VM.

• It checks the performance of the application running on the Windows VMs.

Use cases

• Windows CPU stress determines the resilience of an application when stress is applied on the CPU resources of Windows VM.
• Windows CPU stress simulates the situation of lack of CPU for processes running on the application, which degrades their performance.
• It helps verify metrics-based horizontal pod autoscaling as well as vertical autoscale, that is, demand based CPU addition.
• It verifies the autopilot functionality of cloud managed clusters.

Prerequisites

• Ensure that the prerequisites are fulfilled before executing the experiment.

Mandatory tunables

Tunable	Description	Notes
CPU_CORES	Number of CPU cores subject to CPU stress.	CPU_CORES and CPU_PERCENTAGE are mututally exclusive, and if values for both there tunables are provided, the latter takes precedence. For example, if CPU_CORES is 1 and CPU_PERCENTAGE is 0, one of the cores are stressed. For more information, go to CPU cores.
CPU_PERCENTAGE	Percentage of CPU core that is consumed.	CPU_CORES and CPU_PERCENTAGE are mututally exclusive, and if values for both there tunables are provided, the latter takes precedence. For example, if CPU_CORES is 1 and CPU_PERCENTAGE is 50, 50 percent of the resources are stressed. For more information, go to CPU percentage.
TOTAL_CHAOS_DURATION	Duration that you specify, through which chaos is injected into the target resource (in seconds).	Default: 60s. For more information, go to duration of the chaos.

Optional tunables

Tunable	Description	Notes
RAMP_TIME	Period to wait before and after injecting chaos (in seconds).	For example, 30s. For more information, go to ramp time.

CPU cores

The CPU_CORE environment variable applies stress on the target Windows VM for a specific duration. If the variable is set to 0, the fault consumes all the available CPU resources.

Following YAML snippet illustrates the use of this input variable.

# CPU hog in the Windows VM
apiVersion: litmuschaos.io/v1alpha1
kind: MachineChaosExperiment
metadata:
  infraType: "windows"
spec:
  engineState: "active"
  steps:
    - - name: windows-cpu-stress
  tasks:
    - name: windows-cpu-stress
      infraId: ""
      definition:
        chaos:
          fault: windows-cpu-stress
          env:
           # CPU cores for stress
            - name: CPU_CORES 
              value: '1'

CPU percentage

The CPU_PERCENTAGE environment variable specifies the percentage of stress applied on the target Windows VM for a specific duration. If the variable is set to 0, the fault consumes all the available CPU cores.

Following YAML snippet illustrates the use of this input variable.

# CPU hog in the Windows VM
apiVersion: litmuschaos.io/v1alpha1
kind: MachineChaosExperiment
metadata:
  name: windows-cpu-stress
spec:
  infraType: "windows"
  steps:
    - - name: windows-cpu-stress
  tasks:
    - name: windows-cpu-stress
      infraId: ""
      definition:
        chaos:
          fault: windows-cpu-stress
          env:
           # CPU cores for stress
            - name: CPU_PERCENTAGE 
              value: '50'

note

If both CPU_CORE and CPU_PERCENTAGE are set to 0, no stress is applied on any of the Windows machine resources.