diff --git a/pkg/api/types.go b/pkg/api/types.go
index ca8011fde23..64af4110920 100644
--- a/pkg/api/types.go
+++ b/pkg/api/types.go
@@ -574,7 +574,8 @@ const (
 
 // PodSpec is a description of a pod
 type PodSpec struct {
-	Volumes       []Volume      `json:"volumes"`
+	Volumes []Volume `json:"volumes"`
+	// Required: there must be at least one container in a pod.
 	Containers    []Container   `json:"containers"`
 	RestartPolicy RestartPolicy `json:"restartPolicy,omitempty"`
 	// Required: Set DNS policy.
diff --git a/pkg/api/v1beta1/types.go b/pkg/api/v1beta1/types.go
index 3adb770db03..e1bc92c0899 100644
--- a/pkg/api/v1beta1/types.go
+++ b/pkg/api/v1beta1/types.go
@@ -1066,8 +1066,9 @@ const (
 
 // PodSpec is a description of a pod
 type PodSpec struct {
-	Volumes       []Volume      `json:"volumes" description:"list of volumes that can be mounted by containers belonging to the pod"`
-	Containers    []Container   `json:"containers" description:"list of containers belonging to the pod; containers cannot currently be added or removed"`
+	Volumes []Volume `json:"volumes" description:"list of volumes that can be mounted by containers belonging to the pod"`
+	// Required: there must be at least one container in a pod.
+	Containers    []Container   `json:"containers" description:"list of containers belonging to the pod; containers cannot currently be added or removed; there must be at least one container in a Pod"`
 	RestartPolicy RestartPolicy `json:"restartPolicy,omitempty" description:"restart policy for all containers within the pod; one of RestartPolicyAlways, RestartPolicyOnFailure, RestartPolicyNever"`
 	// Optional: Set DNS policy.  Defaults to "ClusterFirst"
 	DNSPolicy DNSPolicy `json:"dnsPolicy,omitempty" description:"DNS policy for containers within the pod; one of 'ClusterFirst' or 'Default'"`
diff --git a/pkg/api/v1beta2/types.go b/pkg/api/v1beta2/types.go
index c5076b6b101..d5adb6d33da 100644
--- a/pkg/api/v1beta2/types.go
+++ b/pkg/api/v1beta2/types.go
@@ -1128,8 +1128,9 @@ const (
 
 // PodSpec is a description of a pod
 type PodSpec struct {
-	Volumes       []Volume      `json:"volumes" description:"list of volumes that can be mounted by containers belonging to the pod"`
-	Containers    []Container   `json:"containers" description:"list of containers belonging to the pod; containers cannot currently be added or removed"`
+	Volumes []Volume `json:"volumes" description:"list of volumes that can be mounted by containers belonging to the pod"`
+	// Required: there must be at least one container in a pod.
+	Containers    []Container   `json:"containers" description:"list of containers belonging to the pod; containers cannot currently be added or removed; there must be at least one container in a Pod"`
 	RestartPolicy RestartPolicy `json:"restartPolicy,omitempty" description:"restart policy for all containers within the pod; one of RestartPolicyAlways, RestartPolicyOnFailure, RestartPolicyNever"`
 	// Optional: Set DNS policy.  Defaults to "ClusterFirst"
 	DNSPolicy DNSPolicy `json:"dnsPolicy,omitempty" description:"DNS policy for containers within the pod; one of 'ClusterFirst' or 'Default'"`
diff --git a/pkg/api/v1beta3/types.go b/pkg/api/v1beta3/types.go
index 2b47b73a27a..2ddc3e1ce4f 100644
--- a/pkg/api/v1beta3/types.go
+++ b/pkg/api/v1beta3/types.go
@@ -573,8 +573,9 @@ const (
 
 // PodSpec is a description of a pod
 type PodSpec struct {
-	Volumes       []Volume      `json:"volumes" description:"list of volumes that can be mounted by containers belonging to the pod"`
-	Containers    []Container   `json:"containers" description:"list of containers belonging to the pod; cannot be updated; containers cannot currently be added or removed"`
+	Volumes []Volume `json:"volumes" description:"list of volumes that can be mounted by containers belonging to the pod"`
+	// Required: there must be at least one container in a pod.
+	Containers    []Container   `json:"containers" description:"list of containers belonging to the pod; cannot be updated; containers cannot currently be added or removed; there must be at least one container in a Pod"`
 	RestartPolicy RestartPolicy `json:"restartPolicy,omitempty" description:"restart policy for all containers within the pod; one of RestartPolicyAlways, RestartPolicyOnFailure, RestartPolicyNever"`
 	// Optional: Set DNS policy.  Defaults to "ClusterFirst"
 	DNSPolicy DNSPolicy `json:"dnsPolicy,omitempty" description:"DNS policy for containers within the pod; one of 'ClusterFirst' or 'Default'"`