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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.
  • Simulates the situation of time skew for processes running on the application, which degrades their performance.
  • 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 engine 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'