Provide ability to add labels to Cluster object

[wahabmk]

Description

Provide ability to add labels to the Cluster object created when installing a clusterTemplate by:

1. Adding .Values.ClusterLabels to all clusterTemplate helm charts.
2. Using ManagedCluster's own labels via the HMC controller if none have been defined in .Values.ClusterLabels.

Testing

As can be seen from the output below, the .metadata.labels from ManagedCluster have been added to the Cluster object:

➜  ~ kubectl -n hmc-system get managedclusters.hmc.mirantis.com wali-dev-1 --show-labels
NAME         READY   STATUS                    LABELS
wali-dev-1   True    ManagedCluster is ready   labelA=A,labelB=B
➜  ~
➜  ~
➜  ~ kubectl -n hmc-system get cluster --show-labels                                
NAME         CLUSTERCLASS   PHASE         AGE   VERSION   LABELS
wali-dev-1                  Provisioned   13m             app.kubernetes.io/managed-by=Helm,helm.toolkit.fluxcd.io/name=wali-dev-1,helm.toolkit.fluxcd.io/namespace=hmc-system,labelA=A,labelB=B,sveltos-agent=present

[zerospiel]

lgtm, 2 charts-related-mostly-nit comments

[Kshatrix]

It doesn't seem reliable since there's no guarantee that all cluster templates have this field (unless you want to make this field required).

[wahabmk]

Yes, in this approach we are depending on the helm chart for cluster templates to use the clusterLabels value. We do need some way to assign labels to Cluster objects. Maybe the better approach would be?

1. In the HMC controller, use the values defined in clusterLabels in the ManagedCluster spec and patch Cluster to apply those labels to it.
2. Or if clusterLabels is not defined, then use the ManagedCluster's own labels.

[Kshatrix]

My understanding was that clusterSelector in MultiClusterService is supposed to refer hmc ManagedCluster instead of capi Cluster objects. In that case propagation should not be optional. Is my assumption valid?

[wahabmk]

Right now the ClusterSelector metav1.LabelSelector field is fed directly into the the .spec.clusterSelector field for the Sveltos ClusterProfile object. So the label selectors are matching Cluster objects.