GCP VM Instance Stop By Label

Introduction

• It causes power-off of GCP VM instances filtered by a label before bringing it back to the running state after the specified chaos duration.
• It helps to check the performance of the application/process running on the VM instance.
• When the MANAGED_INSTANCE_GROUP is enable then the experiment will not try to start the instances post chaos, instead it will check the addition of new instances to the instance group.

Scenario: stop the gcp vm

Uses

View the uses of the experiment

coming soon

Prerequisites

Verify the prerequisites

• Ensure that Kubernetes Version > 1.16
• Ensure that the Litmus Chaos Operator is running by executing kubectl get pods in operator namespace (typically, litmus).If not, install from here
• Ensure that the gcp-vm-instance-stop-by-label experiment resource is available in the cluster by executing kubectl get chaosexperiments in the desired namespace. If not, install from here
• Ensure that you have sufficient GCP permissions to stop and start the GCP VM instances.

• Ensure to create a Kubernetes secret having the GCP service account credentials in the default namespace. A sample secret file looks like:

  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

View the default validations

• All the VM instances having the target label are in a healthy state

Minimal RBAC configuration example (optional)

NOTE

If you are using this experiment as part of a litmus workflow scheduled constructed & executed from chaos-center, then you may be making use of the litmus-admin RBAC, which is pre installed in the cluster as part of the agent setup.

View the Minimal RBAC permissions

---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: gcp-vm-instance-stop-by-label-sa
  namespace: default
  labels:
    name: gcp-vm-instance-stop-by-label-sa
    app.kubernetes.io/part-of: litmus
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: gcp-vm-instance-stop-by-label-sa
  labels:
    name: gcp-vm-instance-stop-by-label-sa
    app.kubernetes.io/part-of: litmus
rules:
  # Create and monitor the experiment & helper pods
  - apiGroups: [""]
    resources: ["pods"]
    verbs: ["create","delete","get","list","patch","update", "deletecollection"]
  # Performs CRUD operations on the events inside chaosengine and chaosresult
  - apiGroups: [""]
    resources: ["events"]
    verbs: ["create","get","list","patch","update"]
  # Fetch configmaps & secrets details and mount it to the experiment pod (if specified)
  - apiGroups: [""]
    resources: ["secrets","configmaps"]
    verbs: ["get","list",]
  # Track and get the runner, experiment, and helper pods log 
  - apiGroups: [""]
    resources: ["pods/log"]
    verbs: ["get","list","watch"]
  # for configuring and monitor the experiment job by the chaos-runner pod
  - apiGroups: ["batch"]
    resources: ["jobs"]
    verbs: ["create","list","get","delete","deletecollection"]
  # for creation, status polling and deletion of litmus chaos resources used within a chaos workflow
  - apiGroups: ["litmuschaos.io"]
    resources: ["chaosengines","chaosexperiments","chaosresults"]
    verbs: ["create","list","get","patch","update","delete"]
  # for experiment to perform node status checks
  - apiGroups: [""]
    resources: ["nodes"]
    verbs: ["get","list"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: gcp-vm-instance-stop-by-label-sa
  labels:
    name: gcp-vm-instance-stop-by-label-sa
    app.kubernetes.io/part-of: litmus
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: gcp-vm-instance-stop-by-label-sa
subjects:
- kind: ServiceAccount
  name: gcp-vm-instance-stop-by-label-sa
  namespace: default

Use this sample RBAC manifest to create a chaosServiceAccount in the desired (app) namespace. This example consists of the minimum necessary role permissions to execute the experiment.

Experiment tunables

check the experiment tunables

Mandatory Fields

Variables	Description	Notes
GCP_PROJECT_ID	GCP project ID to which the VM instances belong	All the VM instances must belong to a single GCP project
INSTANCE_LABEL	Name of target VM instances	The INSTANCE_LABEL should be provided as key:value or key if the corresponding value is empty ex: vm:target-vm
ZONES	The zone of the target VM instances	Only one zone can be provided i.e. all target instances should lie in the same zone

Optional Fields

Variables	Description	Notes
TOTAL_CHAOS_DURATION	The total time duration for chaos insertion (sec)	Defaults to 30s
CHAOS_INTERVAL	The interval (in sec) between successive instance termination	Defaults to 30s
MANAGED_INSTANCE_GROUP	Set to enable if the target instance is the part of a managed instance group	Defaults to disable
INSTANCE_AFFECTED_PERC	The percentage of total VMs filtered using the label to target	Defaults to 0 (corresponds to 1 instance), provide numeric value only
SEQUENCE	It defines sequence of chaos execution for multiple instance	Default value: parallel. Supported: serial, parallel
RAMP_TIME	Period to wait before and after injection of chaos in sec

Experiment Examples

Common Experiment Tunables

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

Target GCP Instances

It will stop all the instances with filtered by the label INSTANCE_LABEL and corresponding ZONES zone in GCP_PROJECT_ID project.

NOTE: The INSTANCE_LABEL accepts only one label and ZONES also accepts only one zone name. Therefore, all the instances must lie in the same zone.

Use the following example to tune this:

apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  chaosServiceAccount: gcp-vm-instance-stop-by-label-sa
  experiments:
  - name: gcp-vm-instance-stop-by-label
    spec:
      components:
        env:
        - name: INSTANCE_LABEL
          value: 'vm:target-vm'

        - name: ZONES
          value: 'us-east1-b'

        - name: GCP_PROJECT_ID
          value: 'my-project-4513'

        - name: TOTAL_CHAOS_DURATION
          value: '60'

Manged Instance Group

If vm instances belong to a managed instance group then provide the MANAGED_INSTANCE_GROUP as enable else provided it as disable, which is the default value.

Use the following example to tune this:

apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  chaosServiceAccount: gcp-vm-instance-stop-by-label-sa
  experiments:
  - name: gcp-vm-instance-stop-by-label
    spec:
      components:
        env:
        - name: MANAGED_INSTANCE_GROUP
          value: 'enable'

        - name: INSTANCE_LABEL
          value: 'vm:target-vm'

        - name: ZONES
          value: 'us-east1-b'

        - name: GCP_PROJECT_ID
          value: 'my-project-4513'

        - name: TOTAL_CHAOS_DURATION
          value: '60'

Mutiple Iterations Of Chaos

The multiple iterations of chaos can be tuned via setting CHAOS_INTERVAL ENV. Which defines the delay between each iteration of chaos.

Use the following example to tune this:

apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  chaosServiceAccount: gcp-vm-instance-stop-by-label-sa
  experiments:
  - name: gcp-vm-instance-stop-by-label
    spec:
      components:
        env:
        - name: CHAOS_INTERVAL
          value: '15'

        - name: TOTAL_CHAOS_DURATION
          value: '60'

        - name: INSTANCE_LABEL
          value: 'vm:target-vm'

        - name: ZONES
          value: 'us-east1-b'

        - name: GCP_PROJECT_ID
          value: 'my-project-4513'