VMware CPU hog

VMware CPU hog applies stress on the CPU resources on Linux OS based VMware VM.

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

Usage

View the uses of the fault

This fault helps determine how resilient an application is when stress is applied on the CPU resources of a VMware virtual machine. The fault causes CPU stress on the target resource(s). It simulates the situation of lack of CPU for processes running on the application, which degrades their performance. It also helps verify metrics-based horizontal pod autoscaling as well as vertical autoscale, i.e. demand based CPU addition. It helps scalability of nodes based on growth beyond budgeted pods. It verifies the autopilot functionality of (cloud) managed clusters. It benefits include verifying multi-tenant load issues (when the load increases on one container, it does not cause downtime in other containers).

Prerequisites

• Kubernetes > 1.16
• Execution plane is connected to vCenter and the hosts on port 443.
• VMware tool is installed on the target VM with remote execution enabled.
• Adequate vCenter permissions to access the hosts and the VMs.
• Create a Kubernetes secret that has the Vcenter credentials in the CHAOS_NAMESPACE. Below is a sample secret file:

apiVersion: v1
kind: Secret
metadata:
  name: vcenter-secret
  namespace: litmus
type: Opaque
stringData:
    VCENTERSERVER: XXXXXXXXXXX
    VCENTERUSER: XXXXXXXXXXXXX
    VCENTERPASS: XXXXXXXXXXXXX

Note

You can pass the VM credentials as secrets or as a ChaosEngine environment variable.

Default validations

The VM should be in a healthy state.

Fault tunables

Fault tunables

Mandatory fields

Variables	Description	Notes
VM_NAME	Name of the target VM.	For example, ubuntu-vm-1code>.

Optional fields

Variables	Description	Notes
CPU_CORES	Number of CPU cores subject to CPU stress.	Default to 1.
CPU_LOAD	Load exerted on each CPU core (in percentage).	Defaults to 100%.
TOTAL_CHAOS_DURATION	Duration that you specify, through which chaos is injected into the target resource (in seconds).	Defaults to 30s.
CHAOS_INTERVAL	Time interval between two successive instance terminations.	Defaults to 30s.
RAMP_TIME	Period to wait before and after injecting chaos (in seconds).	For example, 30s.
SEQUENCE	Sequence of chaos execution for multiple instances.	Defaults to parallel. Supports serial sequence as well.

Fault examples

Common fault tunables

Refer to the common attributes to tune the common tunables for all the faults.

CPU_CORES

It stresses the CPU_CORE of the target VM for the duration defined by the TOTAL_CHAOS_DURATION environment variable.

Use the following example to tune it:

# CPU hog in the VMware VM
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  chaosServiceAccount: litmus-admin
  experiments:
  - name: VMware-cpu-hog
    spec:
      components:
        env:
        # Name of the VM
        - name: VM_NAME
          value: 'test-vm-01'
       # CPU cores for stress
        - name: CPU_CORES 
          value: '1'

CPU load

It specifies the load exerted on each VM CPU core (in percentage). You can tune it using the CPU_LOAD environment variable.

Use the following example to tune it:

# CPU hog in the VMware VM
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  chaosServiceAccount: litmus-admin
  experiments:
  - name: VMware-cpu-hog
    spec:
      components:
        env:
        # Name of the VM
        - name: VM_NAME
          value: 'test-vm-01'
        # CPU load in percentage for the stress
        - name: CPU_LOAD
          value: '100'