Do not report host deletion as completed on an unknown API error

deleteHost() fetches the host StatefulSet and treats any error from that
Get as "StatefulSet not found - already deleted", emitting a
DeleteCompleted event and returning nil. Only NotFound actually means the
host is gone; a Forbidden, a timeout or any other transient API error
takes the same branch.

That early return skips both deleteTables() - which the surrounding
comment notes is required so ZooKeeper stops tracking the host's tables -
and Controller.deleteHost(), which deletes the host's PVCs. Those PVCs
carry no owner reference (see model/common/creator/pvc.go, where it is
commented out to stay compatible with the PV retain policy), so the
operator's own call is the only thing that ever reclaims them.

Classify the error instead: keep the existing behaviour for NotFound, and
on any other error emit DeleteFailed and return it rather than claiming
the host was deleted. apiErrors.IsNotFound is already used this way
elsewhere in the package, for example in worker-pdb.go.

Signed-off-by: Somanchi Poorna Sobhita <somanchi004@gmail.com>

Author: somanchi004-code

pkg/controller/chi/worker-deleter.go

@@ -20,6 +20,7 @@ import (
 	"time"
 
 	core "k8s.io/api/core/v1"
+	apiErrors "k8s.io/apimachinery/pkg/api/errors"
 	meta "k8s.io/apimachinery/pkg/apis/meta/v1"
 
 	log "github.com/altinity/clickhouse-operator/pkg/announcer"
@@ -539,12 +540,25 @@ func (w *worker) deleteHost(ctx context.Context, chi *api.ClickHouseInstallation
 
 	var err error
 	if host.Runtime.CurStatefulSet, err = w.c.kube.STS().Get(ctx, host); err != nil {
-		w.a.WithEvent(host.GetCR(), a.EventActionDelete, a.EventReasonDeleteCompleted).
-			WithAction(host.GetCR()).
+		if apiErrors.IsNotFound(err) {
+			// StatefulSet is gone for sure - the host is already deleted.
+			w.a.WithEvent(host.GetCR(), a.EventActionDelete, a.EventReasonDeleteCompleted).
+				WithAction(host.GetCR()).
+				M(host).F().
+				Info("Delete host: %s/%s - completed StatefulSet not found - already deleted",
+					host.Runtime.Address.ClusterName, host.GetName())
+			return nil
+		}
+		// Unable to tell whether the StatefulSet exists.
+		// Do not report deletion as completed - the cleanup below is skipped, and the host's
+		// PVCs carry no owner reference (see model/common/creator/pvc.go), so nothing else
+		// would reclaim them. Report the failure and let the caller decide.
+		w.a.WithEvent(host.GetCR(), a.EventActionDelete, a.EventReasonDeleteFailed).
+			WithError(host.GetCR()).
 			M(host).F().
-			Info("Delete host: %s/%s - completed StatefulSet not found - already deleted? err: %v",
+			Error("Delete host: %s/%s - unable to get StatefulSet, host deletion not performed. err: %v",
 				host.Runtime.Address.ClusterName, host.GetName(), err)
-		return nil
+		return err
 	}
 
 	// Pre-delete host hooks: run BEFORE we touch the host's k8s objects so the pod is