OpenShift Container Platform

Creating a ClusterGroupUpgrade CR with pre-caching

For single-node OpenShift, the pre-cache feature allows the required container images to be present on the spoke cluster before the update starts.

For pre-caching, TALM uses the spec.remediationStrategy.timeout value from the ClusterGroupUpgrade CR. You must set a timeout value that allows sufficient time for the pre-caching job to complete. When you enable the ClusterGroupUpgrade CR after pre-caching has completed, you can change the timeout value to a duration that is appropriate for the update.

Prerequisites

Install the Topology Aware Lifecycle Manager (TALM).
Provision one or more managed clusters.
Log in as a user with cluster-admin privileges.

Procedure

Save the contents of the ClusterGroupUpgrade CR with the preCaching field set to true in the clustergroupupgrades-group-du.yaml file:

apiVersion: ran.openshift.io/v1alpha1
kind: ClusterGroupUpgrade
metadata:
  name: du-upgrade-4918
  namespace: ztp-group-du-sno
spec:
  preCaching: true
  clusters:
  - cnfdb1
  - cnfdb2
  enable: false
  managedPolicies:
  - du-upgrade-platform-upgrade
  remediationStrategy:
    maxConcurrency: 2
    timeout: 240

The preCaching field is set to true, which enables TALM to pull the container images before starting the update.

When you want to start pre-caching, apply the ClusterGroupUpgrade CR by running the following command:
```
$ oc apply -f clustergroupupgrades-group-du.yaml
```

Verification

Check if the ClusterGroupUpgrade CR exists in the hub cluster by running the following command:

$ oc get cgu -A

Example output:

NAMESPACE          NAME              AGE   STATE        DETAILS
ztp-group-du-sno   du-upgrade-4918   10s   InProgress   Precaching is required and not done

The CR is created.

Check the status of the pre-caching task by running the following command:

$ oc get cgu -n ztp-group-du-sno du-upgrade-4918 -o jsonpath='{.status}'

Example output:

{
  "conditions": [
    {
      "lastTransitionTime": "2022-01-27T19:07:24Z",
      "message": "Precaching is required and not done",
      "reason": "InProgress",
      "status": "False",
      "type": "PrecachingSucceeded"
    },
    {
      "lastTransitionTime": "2022-01-27T19:07:34Z",
      "message": "Pre-caching spec is valid and consistent",
      "reason": "PrecacheSpecIsWellFormed",
      "status": "True",
      "type": "PrecacheSpecValid"
    }
  ],
  "precaching": {
    "clusters": [
      "cnfdb1"
      "cnfdb2"
    ],
    "spec": {
      "platformImage": "image.example.io"},
    "status": {
      "cnfdb1": "Active"
      "cnfdb2": "Succeeded"}
    }
}

The output lists the identified clusters. The platformImage value in status.precaching.spec is derived by TALM from the ClusterVersion object in the managed policies.

Check the status of the pre-caching job by running the following command on the spoke cluster:

$ oc get jobs,pods -n openshift-talo-pre-cache

Example output:

NAME                  COMPLETIONS   DURATION   AGE
job.batch/pre-cache   0/1           3m10s      3m10s

NAME                     READY   STATUS    RESTARTS   AGE
pod/pre-cache--1-9bmlr   1/1     Running   0          3m10s

Check the status of the ClusterGroupUpgrade CR by running the following command:

$ oc get cgu -n ztp-group-du-sno du-upgrade-4918 -o jsonpath='{.status}'

Example output:

"conditions": [
    {
      "lastTransitionTime": "2022-01-27T19:30:41Z",
      "message": "The ClusterGroupUpgrade CR has all clusters compliant with all the managed policies",
      "reason": "UpgradeCompleted",
      "status": "True",
      "type": "Ready"
    },
    {
      "lastTransitionTime": "2022-01-27T19:28:57Z",
      "message": "Precaching is completed",
      "reason": "PrecachingCompleted",
      "status": "True",
      "type": "PrecachingSucceeded"
    }

The pre-cache tasks are done.