treewide: add missing error handling

Change-Id: I55ccf3ff490b58f6af93e665c668428acddc8d65
Reviewed-on: https://review.monogon.dev/c/monogon/+/3019
Vouch-Run-CI: Tim Windelschmidt <tim@monogon.tech>
Tested-by: Jenkins CI
Reviewed-by: Serge Bazanski <serge@monogon.tech>
diff --git a/metropolis/node/kubernetes/service_controller.go b/metropolis/node/kubernetes/service_controller.go
index ccb5b29..c1cec27 100644
--- a/metropolis/node/kubernetes/service_controller.go
+++ b/metropolis/node/kubernetes/service_controller.go
@@ -85,6 +85,9 @@
 	}
 
 	clientConfig, err := rawClientConfig.ClientConfig()
+	if err != nil {
+		return fmt.Errorf("could not fetch generate client config: %w", err)
+	}
 	clientSet, err := kubernetes.NewForConfig(clientConfig)
 	if err != nil {
 		return fmt.Errorf("could not generate kubernetes client: %w", err)