feat: add drain delay (#852)

Signed-off-by: Daniel Malon <daniel.malon@me.com>

cmd/kured/main.go

@@ -44,6 +44,7 @@ var (
 
 	// Command line flags
 	forceReboot                     bool
+	drainDelay                      time.Duration
 	drainTimeout                    time.Duration
 	rebootDelay                     time.Duration
 	period                          time.Duration
@@ -139,6 +140,8 @@ func NewRootCommand() *cobra.Command {
 		"only drain pods with labels matching the selector (default: '', all pods)")
 	rootCmd.PersistentFlags().IntVar(&skipWaitForDeleteTimeoutSeconds, "skip-wait-for-delete-timeout", 0,
 		"when seconds is greater than zero, skip waiting for the pods whose deletion timestamp is older than N seconds while draining a node")
+	rootCmd.PersistentFlags().DurationVar(&drainDelay, "drain-delay", 0,
+		"delay drain for this duration (default: 0, disabled)")
 	rootCmd.PersistentFlags().DurationVar(&drainTimeout, "drain-timeout", 0,
 		"timeout after which the drain is aborted (default: 0, infinite time)")
 	rootCmd.PersistentFlags().DurationVar(&rebootDelay, "reboot-delay", 0,
@@ -497,6 +500,11 @@ func drain(client *kubernetes.Clientset, node *v1.Node) error {
 		updateNodeLabels(client, node, preRebootNodeLabels)
 	}
 
+	if drainDelay > 0 {
+		log.Infof("Delaying drain for %v", drainDelay)
+		time.Sleep(drainDelay)
+	}
+
 	log.Infof("Draining node %s", nodename)
 
 	if notifyURL != "" {

kured-ds.yaml

@@ -53,6 +53,7 @@ spec:
 #            - --force-reboot=false
 #            - --drain-grace-period=-1
 #            - --skip-wait-for-delete-timeout=0
+#            - --drain-delay=0
 #            - --drain-timeout=0
 #            - --drain-pod-selector=""
 #            - --period=1h