Updating a Single Standalone Cluster#

k0rdent ClusterTemplate objects are immutable, so the only way to change a ClusterDeployment is to change the template that forms its basis.

To update the ClusterDeployment, modify the .spec.template field to use the name of the new ClusterTemplate. This enables you to apply changes to the cluster configuration. These changes will then be applied to the actual cluster. For example, if the cluster currently uses t2.large instances, that will be specified in its current template. To change the cluster to use t2.xlarge instances, you would simply apply a template that references that new size; k0rdent will then realize the cluster is out of sync and will attempt to remedy the situation by updating the cluster.

Follow these steps to update the ClusterDeployment:

Patch the ClusterDeployment with the new template

Run the following command, replacing the placeholders with the appropriate values:

kubectl patch clusterdeployment.kcm <cluster-name> -n <namespace> --patch '{"spec":{"template":"<new-template-name>"}}' --type=merge

Check the status of the ClusterDeployment

After applying the patch, verify the status of the ClusterDeployment object:
```
kubectl get clusterdeployment.kcm <cluster-name> -n <namespace>
```
Inspect the detailed status

For more details, use the -o=yaml option to check the .status.conditions field:
```
kubectl get clusterdeployment.kcm <cluster-name> -n <namespace> -o=yaml
```

Note that not all updates are possible; ClusterTemplateChain objects limit what templates can be applied. Consider, for example, this ClusterTemplateChain:

apiVersion: k0rdent.mirantis.com/v1alpha1
kind: ClusterTemplateChain
metadata:
  name: aws-standalone-cp-0-2-0
  namespace: kcm-system
spec:
  supportedTemplates:
    - name: aws-standalone-cp-0-0-2
      availableUpgrades:
        - name: aws-standalone-cp-0-2-0
    - name: aws-standalone-cp-0-2-0

As you can see from the .spec, the aws-standalone-cp-0-2-0 template can be applied to a cluster that also uses the aws-standalone-cp-0-2-0 template, or it can be used as an upgrade from a cluster that uses aws-standalone-cp-0.0.2. You wouldn't be able to use this template to update a cluster that uses any other ClusterTemplate.

Similarly, the AccessManagement object must have properly configured spec.accessRules with a list of allowed ClusterTemplateChain object names and their namespaces. For more information, see Template Life Cycle Management.

Note

Support for displaying all available Cluster Templates for updates in the ClusterDeployment status is planned.