iptables reset text message

Signed-off-by: Ruben Orduz <rubenoz@gmail.com>

cmd/kubeadm/app/cmd/reset.go

@@ -27,10 +27,9 @@ import (
 	"strings"
 
 	"github.com/spf13/cobra"
-	"k8s.io/klog"
-
 	"k8s.io/apimachinery/pkg/util/sets"
 	clientset "k8s.io/client-go/kubernetes"
+	"k8s.io/klog"
 	kubeadmapiv1beta1 "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta1"
 	"k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/validation"
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/options"
@@ -166,6 +165,7 @@ func (r *Reset) Run(out io.Writer, client clientset.Interface) error {
 	if err := removeContainers(utilsexec.New(), r.criSocketPath); err != nil {
 		klog.Errorf("[reset] failed to remove containers: %+v", err)
 	}
+
 	dirsToClean = append(dirsToClean, []string{kubeadmconstants.KubeletRunDirectory, "/etc/cni/net.d", "/var/lib/dockershim", "/var/run/kubernetes"}...)
 
 	// Then clean contents from the stateful kubelet, etcd and cni directories
@@ -182,6 +182,18 @@ func (r *Reset) Run(out io.Writer, client clientset.Interface) error {
 	}
 	resetConfigDir(kubeadmconstants.KubernetesDir, r.certsDir)
 
+	// Output help text instructing user how to remove iptables rules
+	msg := `
+	The reset process does not reset or clean up iptables rules or IPVS tables.
+	If you wish to reset iptables, you must do so manually.
+	For example: 
+	iptables -F && iptables -t nat -F && iptables -t mangle -F && iptables -X
+
+	If your cluster was setup to utilize IPVS, run ipvsadm --clear (or similar)
+	to reset your system's IPVS tables.
+	`
+	fmt.Print(msg)
+
 	return nil
 }