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GCP VM disk loss by label

GCP VM disk loss by label disrupts the state of GCP persistent disk volume filtered using a label by detaching it from its VM instance for a specific duration.

GCP VM Disk Loss By Label

Usage​

View fault usage
This fault can be used to determine the resilience of the GKE infrastructure. It helps determine how quickly a node can recover when a persistent disk volume is detached from the VM instance associated with it.

Prerequisites​

  • Kubernetes > 1.16.
  • Service account should have editor access (or owner access) to the GCP project.
  • Target disk volume should not be a boot disk of any VM instance.
  • Kubernetes secret that has the GCP service account credentials in the default namespace. Below is a sample secret file:
apiVersion: v1
kind: Secret
metadata:
  name: cloud-secret
type: Opaque
stringData:
  type:
  project_id:
  private_key_id:
  private_key:
  client_email:
  client_id:
  auth_uri:
  token_uri:
  auth_provider_x509_cert_url:
  client_x509_cert_url:

Default validations​

All the disk volumes that have the target label are attached to their respective instances.

Fault tunables​

Fault tunables

Mandatory Fields

Variables Description Notes
GCP_PROJECT_ID The ID of the GCP project, of which the disk volumes are a part. All the target disk volumes should belong to a single GCP project.
DISK_VOLUME_LABEL Label of the target non-boot persistent disk volume. This value is provided as a key:value pair or as a key if the corresponding value is empty. For example, disk:target-disk.
ZONES The zone of the target disk volumes. Only one zone is provided, which indicates that all target disks reside in the same zone.

Optional Fields

Variables Description Notes
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 chaos iterations (in seconds). Defaults to 30s.
DISK_AFFECTED_PERC Percentage of total disks that are filtered using the target label (specify numeric values only. Defaults to 0 (that corresponds to 1 disk).
SEQUENCE Sequence of chaos execution for multiple target disks. Defaults to parallel. It supports serial sequence as well.
RAMP_TIME Period to wait before and after injecting chaos (in seconds). For example, 30s.

Fault examples​

Common fault tunables​

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

Detach volumes by label​

It contains the label of disk volumes that are subject to disk loss. It detaches all the disks with the DISK_VOLUME_LABEL label in the ZONES zone within the GCP_PROJECT_ID project. It re-attaches the disk volume after waiting for the duration specified by TOTAL_CHAOS_DURATION environment variable.

NOTE: The DISK_VOLUME_LABEL accepts only one label and ZONES accepts only one zone name. Therefore, all the disks must reside in the same zone.

Use the following example to tune it:

apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  chaosServiceAccount: litmus-admin
  experiments:
  - name: gcp-vm-disk-loss-by-label
    spec:
      components:
        env:
        - name: DISK_VOLUME_LABEL
          value: 'disk:target-disk'
        - name: ZONES
          value: 'us-east1-b'
        - name: GCP_PROJECT_ID
          value: 'my-project-4513'
        - name: TOTAL_CHAOS_DURATION
          VALUE: '60'