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VMware disk loss

VMware disk loss detaches the disks that are attached to a Linux OS based VMware VM.

VMware Disk Loss

Use cases​

  • VMware disk loss determines the resilience of an application to the unplanned scaling of K8s pods.

Prerequisites​

  • Kubernetes > 1.16 is required to execute this fault.
  • The VM should be in a healthy state before and after injecting chaos.
  • The target disks should be attached to the VM.
  • 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.
  • Appropriate vCenter permissions should be provided 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

Mandatory tunables​

Tunable Description Notes
APP_VM_MOIDS MOIDs of the VMware instance. After you open the VM in VCenter WebClient, you can find the MOID in the address field (VirtualMachine:vm-5365). Alternatively you can use the CLI to fetch the MOID. For example, vm-5365. For more information, go to MOIDs of the VMware instance.
VIRTUAL_DISK_NAMES Name of the target disks provided as comma-separated values. For example, disk-1.vmdk,disk-2.vmdk. For more information, go to virtual disk names.

Optional tunables​

Tunable Description Notes
TOTAL_CHAOS_DURATION Duration that you specify, through which chaos is injected into the target resource (in seconds). Defaults to 30s. For more information, go to duration of the chaos.
CHAOS_INTERVAL Time interval between two successive instance terminations (in seconds). Defaults to 30s. For more information, go to chaos interval.
SEQUENCE Sequence of chaos execution for multiple instances. Defaults to parallel. Supports serial sequence as well. For more information, go to sequence of chaos execution.
RAMP_TIME Period to wait before and after injecting chaos (in seconds). For example, 30s. For more information, go to ramp time.
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.

Virtual disk names​

It specifies the name of the target disks attached to a particular VM. Tune it by using the VIRTUAL_DISK_NAMES environment variable.

Use the following example to tune it:

# Disk loss in the VMware VM
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  chaosServiceAccount: litmus-admin
  experiments:
  - name: VMware-disk-loss
    spec:
      components:
        env:
        # Name of the VM
        - name: APP_VM_MOIDS
          value: 'vm-2055'
        # Name of target disk
        - name: VIRTUAL_DISK_NAMES
          value: 'disk-1.vmdk'