## 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. !!! tip "Scenario: Stop the azure instance" ![Azure Instance Stop](../../images/azure-instance-stop.png) ## Uses ??? info "View the uses of the experiment" coming soon ## Prerequisites ??? info "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 ](https://docs.microsoft.com/en-us/azure/developer/go/azure-sdk-authorization#use-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: ```yaml 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.yaml`with the same name. ## Default Validations ??? info "View the default validations" - Azure instance should be in healthy state. ## Minimal RBAC configuration example (optional) !!! tip "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](https://litmuschaos.github.io/litmus/litmus-admin-rbac.yaml) RBAC, which is pre installed in the cluster as part of the agent setup. ??? note "View the Minimal RBAC permissions" [embedmd]:# (https://raw.githubusercontent.com/litmuschaos/chaos-charts/master/charts/azure/azure-instance-stop/rbac.yaml yaml) ```yaml --- 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: - apiGroups: [""] resources: ["pods","events","secrets"] verbs: ["create","list","get","patch","update","delete","deletecollection"] - apiGroups: [""] resources: ["pods/exec","pods/log"] verbs: ["create","list","get"] - apiGroups: ["batch"] resources: ["jobs"] verbs: ["create","list","get","delete","deletecollection"] - apiGroups: ["litmuschaos.io"] resources: ["chaosengines","chaosexperiments","chaosresults"] verbs: ["create","list","get","patch","update"] --- 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 ??? info "check the experiment tunables"

Mandatory Fields

Variables Description Notes
AZURE_INSTANCE_NAME 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](../common/common-tunables-for-all-experiments.md) 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: [embedmd]:# (https://raw.githubusercontent.com/litmuschaos/litmus/master/mkdocs/docs/experiments/categories/azure/azure-instance-stop/azure-instance.yaml yaml) ```yaml ## 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_NAME value: 'instance-01,instance-02' # name of the resource group - name: RESOURCE_GROUP value: '' - 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: [embedmd]:# (https://raw.githubusercontent.com/litmuschaos/litmus/master/mkdocs/docs/experiments/categories/azure/azure-instance-stop/azure-scale-set-instance.yaml yaml) ```yaml ## 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_NAME value: 'instance-01,instance-02' # name of the resource group - name: RESOURCE_GROUP value: '' # 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: [embedmd]:# (https://raw.githubusercontent.com/litmuschaos/litmus/master/mkdocs/docs/experiments/categories/azure/azure-instance-stop/chaos-interval.yaml yaml) ```yaml # 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_NAME value: 'instance-01,instance-02' - name: RESOURCE_GROUP value: '' ```