Clarify MinAvailable approval semantics.

pkg/apis/policy/types.go

@@ -24,8 +24,10 @@ import (
 
 // PodDisruptionBudgetSpec is a description of a PodDisruptionBudget.
 type PodDisruptionBudgetSpec struct {
-	// The minimum number of pods that must be available simultaneously.  This
-	// can be either an integer or a string specifying a percentage, e.g. "28%".
+	// An eviction is allowed if at least "minAvailable" pods selected by
+	// "selector" will still be available after the eviction, i.e. even in the
+	// absence of the evicted pod.  So for example you can prevent all voluntary
+	// evictions by specifying "100%".
 	MinAvailable intstr.IntOrString `json:"minAvailable,omitempty"`
 
 	// Label query over pods whose evictions are managed by the disruption

pkg/apis/policy/v1alpha1/types.go

@@ -24,8 +24,10 @@ import (
 
 // PodDisruptionBudgetSpec is a description of a PodDisruptionBudget.
 type PodDisruptionBudgetSpec struct {
-	// The minimum number of pods that must be available simultaneously.  This
-	// can be either an integer or a string specifying a percentage, e.g. "28%".
+	// An eviction is allowed if at least "minAvailable" pods selected by
+	// "selector" will still be available after the eviction, i.e. even in the
+	// absence of the evicted pod.  So for example you can prevent all voluntary
+	// evictions by specifying "100%".
 	MinAvailable intstr.IntOrString `json:"minAvailable,omitempty" protobuf:"bytes,1,opt,name=minAvailable"`
 
 	// Label query over pods whose evictions are managed by the disruption