Support opaque integer resource accounting.

- Prevents kubelet from overwriting capacity during sync.
- Handles opaque integer resources in the scheduler.
  - Adds scheduler predicate tests for opaque resources.
- Validates opaque int resources:
  - Ensures supplied opaque int quantities in node capacity,
    node allocatable, pod request and pod limit are integers.
  - Adds tests for new validation logic (node update and pod spec).
- Added e2e tests for opaque integer resources.

pkg/api/types.go

@@ -2631,6 +2631,11 @@ const (
 	// Number of Pods that may be running on this Node: see ResourcePods
 )
 
+const (
+	// Namespace prefix for opaque counted resources (alpha).
+	ResourceOpaqueIntPrefix = "pod.alpha.kubernetes.io/opaque-int-resource-"
+)
+
 // ResourceList is a set of (resource name, quantity) pairs.
 type ResourceList map[ResourceName]resource.Quantity