Allow admin user to explicitly unschedule the node

Setting Unschedulable on the node will not touch any existing pods
on the node but will block scheduling of new pods on the node.

pkg/api/v1beta1/conversion.go

@@ -711,6 +711,7 @@ func init() {
 			}
 			out.PodCIDR = in.Spec.PodCIDR
 			out.ExternalID = in.Spec.ExternalID
+			out.Unschedulable = in.Spec.Unschedulable
 			return s.Convert(&in.Spec.Capacity, &out.NodeResources.Capacity, 0)
 		},
 		func(in *Minion, out *newer.Node, s conversion.Scope) error {
@@ -742,6 +743,7 @@ func init() {
 			}
 			out.Spec.PodCIDR = in.PodCIDR
 			out.Spec.ExternalID = in.ExternalID
+			out.Spec.Unschedulable = in.Unschedulable
 			return s.Convert(&in.NodeResources.Capacity, &out.Spec.Capacity, 0)
 		},
 

pkg/api/v1beta1/types.go

@@ -677,6 +677,8 @@ const (
 	NodeReachable NodeConditionKind = "Reachable"
 	// NodeReady means the node returns StatusOK for HTTP health check.
 	NodeReady NodeConditionKind = "Ready"
+	// NodeSchedulable means the node is ready to accept new pods.
+	NodeSchedulable NodeConditionKind = "Schedulable"
 )
 
 type NodeCondition struct {
@@ -731,6 +733,8 @@ type Minion struct {
 	NodeResources NodeResources `json:"resources,omitempty" description:"characterization of node resources"`
 	// Pod IP range assigned to the node
 	PodCIDR string `json:"podCIDR,omitempty" description:"IP range assigned to the node"`
+	// Unschedulable controls node schedulability of new pods. By default node is schedulable.
+	Unschedulable bool `json:"unschedulable,omitempty" description:"disable pod scheduling on the node"`
 	// Status describes the current status of a node
 	Status NodeStatus `json:"status,omitempty" description:"current status of node"`
 	// Labels for the node