Merge pull request #10826 from olemarkus/automated-cherry-pick-of-#10…

…328-origin-release-1.19

Automated cherry pick of #10328: Don't try to detach masters

pkg/instancegroups/instancegroups.go

@@ -603,13 +603,14 @@ func (c *RollingUpdateCluster) UpdateSingleInstance(cloudMember *cloudinstances.
 		if cloudMember.CloudInstanceGroup.InstanceGroup.IsMaster() {
 			klog.Warning("cannot detach master instances. Assuming --surge=false")
 
-		}
-		err := c.detachInstance(cloudMember)
-		if err != nil {
-			return fmt.Errorf("failed to detach instance: %v", err)
-		}
-		if err := c.maybeValidate(" after detaching instance", c.ValidateCount); err != nil {
-			return err
+		} else {
+			err := c.detachInstance(cloudMember)
+			if err != nil {
+				return fmt.Errorf("failed to detach instance: %v", err)
+			}
+			if err := c.maybeValidate(" after detaching instance", c.ValidateCount); err != nil {
+				return err
+			}
 		}
 	}