Document CRD not found errors

Signed-off-by: Nolan Brubaker <nolan@heptio.com>

docs/faq.md

@@ -35,4 +35,9 @@ Related to this, if you need to restore a backup from cluster A into cluster B,
 mode in cluster B's Ark instance while it's configured to use cluster A's bucket. This will ensure no 
 new backups are created, and no existing backups are deleted or overwritten.
 
+## I receive 'custom resource not found' errors when starting up the Ark server
+
+Ark's server will not start if the required Custom Resource Definitions are not found in Kubernetes. Apply
+the `examples/common/00-prereqs.yaml` file to create these defintions, then restart Ark.
+
 [1]: config-definition.md#main-config-parameters

pkg/cmd/server/server.go

@@ -328,7 +328,7 @@ func (s *server) arkResourcesExist() error {
 	}
 
 	if arkGroupVersion == nil {
-		return errors.Errorf("Ark API group %s not found", api.SchemeGroupVersion)
+		return errors.Errorf("Ark API group %s not found. Apply examples/common/00-prereqs.yaml to create it.", api.SchemeGroupVersion)
 	}
 
 	foundResources := sets.NewString()
@@ -347,6 +347,7 @@ func (s *server) arkResourcesExist() error {
 	}
 
 	if len(errs) > 0 {
+		errs = append(errs, errors.New("Ark custom resources not found - apply examples/common/00-prereqs.yaml to update the custom resource definitions"))
 		return kubeerrs.NewAggregate(errs)
 	}