Project: Litmus (Observability and Analysis / Chaos Engineering)
File: gcp-vm-disk-loss.md

It causes chaos to disrupt state of GCP persistent disk volume by detaching it from its VM instance for a certain chaos duration using the disk name. !!! tip "Scenario: detach the gcp disk" ??? info "View the uses of the experiment" coming soon ??? info "Verify the prerequisites" Ensure that Kubernetes Version > 1.16 Ensure that the Litmus Chaos Operator is running by executing <code>kubectl get pods</code> in operator namespace (typically, <code>litmus</code>).If not, install from <a href="https://v1-docs.litmuschaos.io/docs/getstarted/#install-litmus">here</a> Ensure that the <code>gcp-vm-disk-loss</code> experiment resource is available in the cluster by executing <code>kubectl get chaosexperiments</code> in the desired namespace. If not, install from <a href="https://hub.litmuschaos.io/api/chaos/master?file=faults/gcp/gcp-vm-disk-loss/fault.yaml">here</a> Ensure that your service account has an editor access or owner access for the GCP project. Ensure that the target disk volume is not a boot disk of any VM instance. 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: privatekeyid: private_key: client_email: client_id: auth_uri: token_uri: authproviderx509certurl: clientx509cert_url: ``` ??? info "View the default validations" Disk volumes are attached to their respective instances !!! 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 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-disk-loss-sa namespace: default labels: name: gcp-vm-disk-loss-sa app.kubernetes.io/part-of: litmus apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRole metadata: name: gcp-vm-disk-loss-sa labels: name: gcp-vm-disk-loss-sa app.kubernetes.io/part-of: litmus rules: apiGroups: [""] resources: ["pods"] verbs: ["create","delete","get","list","patch","update", "deletecollection"] apiGroups: [""] resources: ["events"] verbs: ["create","get","list","patch","update"] apiGroups: [""] resources: ["secrets","configmaps"] verbs: ["get","list",] apiGroups: [""] resources: ["pods/log"] verbs: ["get","list","watch"] apiGroups: [""] resources: ["pods/exec"] verbs: ["get","list","create"] apiGroups: ["batch"] resources: ["jobs"] verbs: ["create","list","get","delete","deletecollection"] apiGroups: ["litmuschaos.io"] resources: ["chaosengines","chaosexperiments","chaosresults"] verbs: ["create","list","get","patch","update","delete"] apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRoleBinding metadata: name: gcp-vm-disk-loss-sa labels: name: gcp-vm-disk-loss-sa app.kubernetes.io/part-of: litmus roleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: gcp-vm-disk-loss-sa subjects: kind: ServiceAccount name: gcp-vm-disk-loss-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

??? info "check the experiment tunables" <h2>Mandatory Fields</h2> <table> <tr> <th> Variables </th> <th> Description </th> <th> Notes </th> </tr> <tr> <td> GCPPROJECTID </td> <td> The ID of the GCP Project of which the disk volumes are a part of </td> <td> All the target disk volumes should belong to a single GCP Project </td> </tr> <tr> <td> DISKVOLUMENAMES </td> <td> Target non-boot persistent disk volume names</td> <td> Multiple disk volume names can be provided as disk1,disk2,... </td> </tr> <tr> <td> ZONES </td> <td> The zones of respective target disk volumes </td> <td> Provide the zone for every target disk name as zone1,zone2... in the respective order of <code>DISKVOLUMENAMES</code> </td> </tr> <tr> <td> DEVICE_NAMES </td> <td> The device names of respective target disk volumes </td> <td> Provide the device name for every target disk name as deviceName1,deviceName2... in the respective order of <code>DISKVOLUMENAMES</code> </td> </tr> </table> <h2>Optional Fields</h2> <table> <tr> <th> Variables </th> <th> Description </th> <th> Notes </th> </tr> <tr> <td> TOTALCHAOSDURATION </td> <td> The total time duration for chaos insertion (sec) </td> <td> Defaults to 30s </td> </tr> <tr> <td> CHAOS_INTERVAL </td> <td> The interval (in sec) between the successive chaos iterations (sec) </td> <td> Defaults to 30s </td> </tr> <tr> <td> SEQUENCE </td> <td> It defines sequence of chaos execution for multiple disks </td> <td> Default value: parallel. Supported: serial, parallel </td> </tr> <tr> <td> RAMP_TIME </td> <td> Period to wait before and after injection of chaos in sec </td> <td> </td> </tr> </table> Refer the to tune the common tunables for all the experiments. It contains comma separated list of volume names subjected to disk loss chaos. It will detach all the disks with the given `DISKVOLUMENAMES` disk names and corresponding `ZONES` zone names and the `DEVICENAMES` device names in `GCPPROJECTID` project. It reattached the volume after waiting for the specified `TOTALCHAOS_DURATION` duration. `NOTE:` The `DISKVOLUMENAMES` contains multiple comma-separated disk names. The comma-separated zone names should be provided in the same order as disk names. Use the following example to tune this: ```yaml apiVersion: litmuschaos.io/v1alpha1 kind: ChaosEngine metadata: name: engine-nginx spec: engineState: "active" annotationCheck: "false" chaosServiceAccount: gcp-vm-disk-loss-sa experiments: name: gcp-vm-disk-loss spec: components: env: name: DISKVOLUMENAMES value: 'disk-01,disk-02' name: ZONES value: 'zone-01,zone-02' name: DEVICE_NAMES value: 'device-01,device-02' name: GCPPROJECTID value: 'project-id' name: TOTALCHAOSDURATION value: '60' ``` 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: ```yaml apiVersion: litmuschaos.io/v1alpha1 kind: ChaosEngine metadata: name: engine-nginx spec: engineState: "active" annotationCheck: "false" chaosServiceAccount: gcp-vm-disk-loss-sa experiments: name: gcp-vm-disk-loss spec: components: env: name: CHAOS_INTERVAL value: '15' name: TOTALCHAOSDURATION value: '60' name: DISKVOLUMENAMES value: 'disk-01,disk-02' name: ZONES value: 'zone-01,zone-02' name: DEVICE_NAMES value: 'device-01,device-02' name: GCPPROJECTID value: 'project-id' ```