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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'