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VMware Windows Time Chaos

VMware Windows Time Chaos simulates a time skew scenario on Windows OS based VMware VM.

  • It checks the performance of the application running on the VMware Windows VMs under time skew conditions.

VMware Windows Time Chaos

Use cases​

  • VMware Windows Time Chaos determines the resilience of an application when a time skew scenario is simulated on a VMware Windows virtual machine.
  • VMware Windows Time Chaos simulates the situation of time skew for processes running on the application, which degrades their performance.
  • It also helps verify the application's ability to handle time failures and its failover mechanisms.

Prerequisites​

  • Kubernetes > 1.16 is required to execute this fault.

  • Execution plane should be connected to vCenter and host vCenter on port 443.

  • VMware tool should be installed on the target VM with remote execution enabled.

  • Adequate vCenter permissions should be provided to access the hosts and the VMs.

  • The VM should be in a healthy state before and after injecting chaos.

  • Kubernetes secret has to be created that has the Vcenter credentials in the CHAOS_NAMESPACE.

  • Run the fault with a user possessing admin rights, preferably the built-in Administrator, to guarantee permissions for memory stress testing. See how to enable the built-in Administrator in Windows.

  • VM credentials can be passed as secrets or as a chaos enginer environment variable.

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

Mandatory tunables​

Tunable Description Notes
VM_NAME Name of the target VM. For example, win-vm-1
VM_USER_NAME Username of the target VM. For example, vm-user.
VM_PASSWORD User password for the target VM. For example, 1234. Note: You can take the password from secret as well.

Optional tunables​

Tunable Description Notes
OFFSET Time offset to induce in the VM. For example, +24h. For more information, go to offset.
TOTAL_CHAOS_DURATION Duration that you specify, through which chaos is injected into the target resource (in seconds). Default: 60 s. For more information, go to duration of the chaos.
RAMP_TIME Period to wait before and after injecting chaos (in seconds). Default: 0 s. For more information, go to ramp time.
SEQUENCE Sequence of chaos execution for multiple instances. Default: parallel. Supports serial and parallel sequence. For more information, go to sequence of chaos execution.
DEFAULT_HEALTH_CHECKDetermines if you wish to run the default health check which is present inside the fault. Default: 'true'. For more information, go to default health check.

Offset​

The OFFSET environment variable specifies the time offset to induce in the target Windows VM.

Use the following example to specify time offset:

apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  chaosServiceAccount: litmus-admin
  experiments:
  - name: vmware-windows-time-chaos
    spec:
      components:
        env:
        # Name of the VM
        - name: VM_NAME
          value: 'test-vm-01'
       # Time offset to induce
        - name: OFFSET 
          value: '+24h'