Azure Instance Stop

Introduction¶

It causes PowerOff an Azure instance before bringing it back to running state after the specified chaos duration.
It helps to check the performance of the application/process running on the instance.

Scenario: Stop the azure instance

Azure Instance Stop

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 azure-instance-stop 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 Azure access to stop and start the an instance.
We will use azure file-based authentication to connect with the instance using azure GO SDK in the experiment. For generating auth file run az ad sp create-for-rbac --sdk-auth > azure.auth Azure CLI command.

Ensure to create a Kubernetes secret having the auth file created in the step in CHAOS_NAMESPACE. A sample secret file looks like:

apiVersion: v1
kind: Secret
metadata:
  name: cloud-secret
type: Opaque
stringData:
  azure.auth: |-
    {
      "clientId": "XXXXXXXXX",
      "clientSecret": "XXXXXXXXX",
      "subscriptionId": "XXXXXXXXX",
      "tenantId": "XXXXXXXXX",
      "activeDirectoryEndpointUrl": "XXXXXXXXX",
      "resourceManagerEndpointUrl": "XXXXXXXXX",
      "activeDirectoryGraphResourceId": "XXXXXXXXX",
      "sqlManagementEndpointUrl": "XXXXXXXXX",
      "galleryEndpointUrl": "XXXXXXXXX",
      "managementEndpointUrl": "XXXXXXXXX"
    }

If you change the secret key name (from azure.auth) please also update the AZURE_AUTH_LOCATION ENV value on experiment.yamlwith the same name.

Default Validations¶

View the default validations

Azure instance should be in 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: azure-instance-stop-sa
  namespace: default
  labels:
    name: azure-instance-stop-sa
    app.kubernetes.io/part-of: litmus
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: azure-instance-stop-sa
  labels:
    name: azure-instance-stop-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 creating and managing to execute comands inside target container
  - apiGroups: [""]
    resources: ["pods/exec"]
    verbs: ["get","list","create"]
  # 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"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: azure-instance-stop-sa
  labels:
    name: azure-instance-stop-sa
    app.kubernetes.io/part-of: litmus
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: azure-instance-stop-sa
subjects:
- kind: ServiceAccount
  name: azure-instance-stop-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
AZURE_INSTANCE_NAMES	Instance name of the target azure instance	For AKS nodes, the instance name is from the scale set section in Azure and not the node name from AKS node pool
RESOURCE_GROUP	The resource group of the target instance

Optional Fields

Variables	Description	Notes
SCALE_SET	Whether instance is part of Scale set	Accepts "enable"/"disable". Default is "disable"
TOTAL_CHAOS_DURATION	The total time duration for chaos insertion (sec)	Defaults to 30s
CHAOS_INTERVAL	The interval (in sec) between successive instance power off.	Defaults to 30s
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.

Stop Instances By Name¶

It contains comma separated list of instance names subjected to instance stop chaos. It can be tuned via AZURE_INSTANCE_NAME ENV.

Use the following example to tune this:

## contains the azure instance details
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  chaosServiceAccount: azure-instance-stop-sa
  experiments:
  - name: azure-instance-stop
    spec:
      components:
        env:
        # comma separated list of azure instance names
        - name: AZURE_INSTANCE_NAMES
          value: 'instance-01,instance-02'
        # name of the resource group
        - name: RESOURCE_GROUP
          value: '<resource group of AZURE_INSTANCE_NAME>'
        - name: TOTAL_CHAOS_DURATION
          value: '60'

Stop Scale Set Instances¶

It contains comma separated list of instance names subjected to instance stop chaos belonging to Scale Set or AKS. It can be tuned via SCALE_SET ENV.

Use the following example to tune this:

## contains the azure instance details for scale set instances or AKS nodes
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  chaosServiceAccount: azure-instance-stop-sa
  experiments:
  - name: azure-instance-stop
    spec:
      components:
        env:
        # comma separated list of azure instance names
        - name: AZURE_INSTANCE_NAMES
          value: 'instance-01,instance-02'
        # name of the resource group
        - name: RESOURCE_GROUP
          value: '<resource group of Scale set>'
        # accepts enable/disable value. default is disable
        - name: SCALE_SET
          value: 'enable'
        - name: TOTAL_CHAOS_DURATION
          value: '60'

Multiple 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:

# defines delay between each successive iteration of the chaos
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  chaosServiceAccount: azure-instance-stop-sa
  experiments:
  - name: azure-instance-stop
    spec:
      components:
        env:
        # delay between each iteration of chaos
        - name: CHAOS_INTERVAL
          value: '10'
         # time duration for the chaos execution
        - name: TOTAL_CHAOS_DURATION
          value: '60'
        - name: AZURE_INSTANCE_NAMES
          value: 'instance-01,instance-02'
        - name: RESOURCE_GROUP
          value: '<resource group of AZURE_INSTANCE_NAME>'