## Introduction - It causes power-off of a GCP VM instance by instance name or list of instance names 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. !!! tip "Scenario: stop the gcp vm" ![GCP VM Instance Stop](../../images/gcp-vm-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 gcp-vm-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 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: ```yaml 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 ??? info "View the default validations" - VM 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" ```yaml --- apiVersion: v1 kind: ServiceAccount metadata: name: gcp-vm-instance-stop-sa namespace: default labels: name: gcp-vm-instance-stop-sa app.kubernetes.io/part-of: litmus --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRole metadata: name: gcp-vm-instance-stop-sa labels: name: gcp-vm-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"] # 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-sa labels: name: gcp-vm-instance-stop-sa app.kubernetes.io/part-of: litmus roleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: gcp-vm-instance-stop-sa subjects: - kind: ServiceAccount name: gcp-vm-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
GCP_PROJECT_ID GCP project ID to which the VM instances belong All the VM instances must belong to a single GCP project
VM_INSTANCE_NAMES Name of target VM instances Multiple instance names can be provided as instance1,instance2,...
ZONES The zones of the target VM instances Zone for every instance name has to be provided as zone1,zone2,... in the same order of VM_INSTANCE_NAMES

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
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. ### Target GCP Instances It will stop all the instances with the given `VM_INSTANCE_NAMES` instance names and corresponding `ZONES` zone names in `GCP_PROJECT_ID` project. `NOTE:` The `VM_INSTANCE_NAMES` contains multiple comma-separated vm instances. The comma-separated zone names should be provided in the same order as instance names. Use the following example to tune this: [embedmd]:# (https://raw.githubusercontent.com/litmuschaos/litmus/master/mkdocs/docs/experiments/categories/gcp/gcp-vm-instance-stop/gcp-instance.yaml yaml) ```yaml ## details of the gcp instance apiVersion: litmuschaos.io/v1alpha1 kind: ChaosEngine metadata: name: engine-nginx spec: engineState: "active" annotationCheck: "false" chaosServiceAccount: gcp-vm-instance-stop-sa experiments: - name: gcp-vm-instance-stop spec: components: env: # comma separated list of vm instance names - name: VM_INSTANCE_NAMES value: 'instance-01,instance-02' # comma separated list of zone names corresponds to the VM_INSTANCE_NAMES # it should be provided in same order of VM_INSTANCE_NAMES - name: ZONES value: 'zone-01,zone-02' # gcp project id to which vm instance belongs - name: GCP_PROJECT_ID value: 'project-id' - name: TOTAL_CHAOS_DURATION value: '60' ``` ### Managed 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: [embedmd]:# (https://raw.githubusercontent.com/litmuschaos/litmus/master/mkdocs/docs/experiments/categories/gcp/gcp-vm-instance-stop/managed-instance-group.yaml yaml) ```yaml ## scale up and down to maintain the available instance counts apiVersion: litmuschaos.io/v1alpha1 kind: ChaosEngine metadata: name: engine-nginx spec: engineState: "active" annotationCheck: "false" chaosServiceAccount: gcp-vm-instance-stop-sa experiments: - name: gcp-vm-instance-stop spec: components: env: # tells if instances are part of managed instance group # supports: enable, disable. default: disable - name: MANAGED_INSTANCE_GROUP value: 'enable' # comma separated list of vm instance names - name: VM_INSTANCE_NAMES value: 'instance-01,instance-02' # comma separated list of zone names corresponds to the VM_INSTANCE_NAMES # it should be provided in same order of VM_INSTANCE_NAMES - name: ZONES value: 'zone-01,zone-02' # gcp project id to which vm instance belongs - name: GCP_PROJECT_ID value: 'project-id' - 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: [embedmd]:# (https://raw.githubusercontent.com/litmuschaos/litmus/master/mkdocs/docs/experiments/categories/gcp/gcp-vm-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: gcp-vm-instance-stop-sa experiments: - name: gcp-vm-instance-stop spec: components: env: # delay between each iteration of chaos - name: CHAOS_INTERVAL value: '15' # time duration for the chaos execution - name: TOTAL_CHAOS_DURATION value: '60' - name: VM_INSTANCE_NAMES value: 'instance-01,instance-02' - name: ZONES value: 'zone-01,zone-02' - name: GCP_PROJECT_ID value: 'project-id' ```