Running cluster checkups

OKD Virtualization 4.11 includes a diagnostic framework to run predefined checkups that can be used for cluster maintenance and troubleshooting.

About the OKD cluster checkup framework

A checkup is an automated test workload that allows you to verify if a specific cluster functionality works as expected. The cluster checkup framework uses native Kubernetes resources to configure and execute the checkup.

By using predefined checkups, cluster administrators can improve cluster maintainability, troubleshoot unexpected behavior, minimize errors, and save time. They can also review the results of the checkup and share them with experts for further analysis. Vendors can write and publish checkups for features or services that they provide and verify that their customer environments are configured correctly.

Running a predefined checkup in the cluster involves setting up the namespace and service account for the framework, creating the ClusterRole and ClusterRoleBinding objects for the service account, enabling permissions for the checkup, and creating the input config map and the checkup job. You can run a checkup multiple times.

Checking network connectivity and latency for virtual machines on a secondary network

As a cluster administrator, you use a predefined checkup to verify network connectivity and measure latency between virtual machines (VMs) that are attached to a secondary network interface.

To run a checkup for the first time, follow the steps in the procedure.

If you have previously run a checkup, skip to step 5 of the procedure because the steps to install the framework and enable permissions for the checkup are not required.

Prerequisites

• You installed the OpenShift CLI (oc).

• You logged in to the cluster as a user with the cluster-admin role.

• The cluster has at least two worker nodes.

• The Multus Container Network Interface (CNI) plug-in is installed on the cluster.

• You configured a network attachment definition for a namespace.

Procedure

1. Create a configuration file that contains the resources to set up the framework. This includes a namespace and service account for the framework, and the ClusterRole and ClusterRoleBinding objects to define permissions for the service account.

   Example framework manifest file

   ---
   apiVersion: v1
   kind: Namespace
   metadata:
     name: kiagnose
   ---
   apiVersion: v1
   kind: ServiceAccount
   metadata:
     name: kiagnose
     namespace: kiagnose
   ---
   apiVersion: rbac.authorization.k8s.io/v1
   kind: ClusterRole
   metadata:
     name: kiagnose
   rules:
     - apiGroups: [ "" ]
       resources: [ "configmaps" ]
       verbs:
         - get
         - list
         - create
         - update
         - patch
     - apiGroups: [ "" ]
       resources: [ "namespaces" ]
       verbs:
         - get
         - list
         - create
         - delete
         - watch
     - apiGroups: [ "" ]
       resources: [ "serviceaccounts" ]
       verbs:
         - get
         - list
         - create
     - apiGroups: [ "rbac.authorization.k8s.io" ]
       resources:
         - roles
         - rolebindings
         - clusterrolebindings
       verbs:
         - get
         - list
         - create
         - delete
     - apiGroups: [ "rbac.authorization.k8s.io" ]
       resources:
         - clusterroles
       verbs:
         - get
         - list
         - create
         - bind
     - apiGroups: [ "batch" ]
       resources: [ "jobs" ]
       verbs:
         - get
         - list
         - create
         - delete
         - watch
   ---
   apiVersion: rbac.authorization.k8s.io/v1
   kind: ClusterRoleBinding
   metadata:
     name: kiagnose
   roleRef:
     apiGroup: rbac.authorization.k8s.io
     kind: ClusterRole
     name: kiagnose
   subjects:
     - kind: ServiceAccount
       name: kiagnose
       namespace: kiagnose
   ...

2. Apply the framework manifest:

   $ oc apply -f <framework_manifest>.yaml

3. Create a configuration file that contains the ClusterRole and Role objects with permissions that the checkup requires for cluster access:

   Example cluster role manifest file

   apiVersion: rbac.authorization.k8s.io/v1
   kind: ClusterRole
   metadata:
     name: kubevirt-vm-latency-checker
   rules:
   - apiGroups: ["kubevirt.io"]
     resources: ["virtualmachineinstances"]
     verbs: ["get", "create", "delete"]
   - apiGroups: ["subresources.kubevirt.io"]
     resources: ["virtualmachineinstances/console"]
     verbs: ["get"]
   - apiGroups: ["k8s.cni.cncf.io"]
     resources: ["network-attachment-definitions"]
     verbs: ["get"]

4. Apply the checkup roles manifest:

   $ oc apply -f <latency_roles>.yaml

5. Create a ConfigMap manifest that contains the input parameters for the checkup. The config map provides the input for the framework to run the checkup and also stores the results of the checkup.

   Example input config map

   apiVersion: v1
   kind: ConfigMap
   metadata:
     name: kubevirt-vm-latency-checkup
     namespace: kiagnose
   data:
     spec.image: registry.redhat.io/container-native-virtualization/vm-network-latency-checkup:v4.11.0
     spec.timeout: 10m
     spec.clusterRoles: |
       kubevirt-vmis-manager
     spec.param.network_attachment_definition_namespace: "default" (1)
     spec.param.network_attachment_definition_name: "bridge-network" (2)
     spec.param.max_desired_latency_milliseconds: "10" (3)
     spec.param.sample_duration_seconds: "5" (4)

   1	The namespace where the NetworkAttachmentDefinition object resides.
   2	The name of the NetworkAttachmentDefinition object.
   3	Optional: The maximum desired latency, in milliseconds, between the virtual machines. If the measured latency exceeds this value, the check fails.
   4	Optional: The duration of the latency check, in seconds.

6. Create the config map in the framework’s namespace:

   $ oc apply -f <latency_config_map>.yaml

7. Create a Job object to run the checkup:

   Example job manifest

   apiVersion: batch/v1
   kind: Job
   metadata:
     name: kubevirt-vm-latency-checkup
     namespace: kiagnose
   spec:
     backoffLimit: 0
     template:
       spec:
         serviceAccount: kiagnose
         restartPolicy: Never
         containers:
           - name: framework
             image: registry.redhat.io/container-native-virtualization/checkup-framework:v4.11.0
             env:
               - name: CONFIGMAP_NAMESPACE
                 value: kiagnose
               - name: CONFIGMAP_NAME
                 value: kubevirt-vm-latency-checkup

8. Apply the Job manifest. The checkup uses the ping utility to verify connectivity and measure latency.

   $ oc apply -f <latency_job>.yaml

9. Wait for the job to complete:

   $ oc wait --for=condition=complete --timeout=10m job.batch/kubevirt-vm-latency-checkup -n kiagnose

10. Review the results of the latency checkup by retrieving the status of the ConfigMap object. If the measured latency is greater than the value of the spec.param.max_desired_latency_milliseconds attribute, the checkup fails and returns an error.

    $ oc get configmap kubevirt-vm-latency-checkup -n kiagnose -o yaml

    Example output config map (success)

    apiVersion: v1
    kind: ConfigMap
    metadata:
     name: kubevirt-vm-latency-checkup
     namespace: kiagnose
    ...
     status.succeeded: "true"
     status.failureReason: ""
     status.result.minLatencyNanoSec: 2000
     status.result.maxLatencyNanoSec: 3000
     status.result.avgLatencyNanoSec: 2500
     status.results.measurementDurationSec: 300
    ...

11. Delete the framework and checkup resources that you previously created. This includes the job, config map, cluster role, and framework manifest files.

    Do not delete the framework and cluster role manifest files if you plan to run another checkup.

    $ oc delete -f <file_name>.yaml

Additional resources

• Attaching a virtual machine to multiple networks