Clarify errors in ProjectedVolume validation

Also clarify API docs.

Author: thockin

api/openapi-spec/swagger.json

@@ -6133,7 +6133,7 @@
             "type": "integer"
           },
           "sources": {
-            "description": "sources is the list of volume projections",
+            "description": "sources is the list of volume projections. Each entry in this list handles one source.",
             "items": {
               "allOf": [
                 {
@@ -8311,7 +8311,7 @@
         "type": "object"
       },
       "io.k8s.api.core.v1.VolumeProjection": {
-        "description": "Projection that may be projected along with other supported volume types",
+        "description": "Projection that may be projected along with other supported volume types. Exactly one of these fields must be set.",
         "properties": {
           "clusterTrustBundle": {
             "allOf": [

api/openapi-spec/v3/api__v1_openapi.json

@@ -4173,7 +4173,7 @@
             "type": "integer"
           },
           "sources": {
-            "description": "sources is the list of volume projections",
+            "description": "sources is the list of volume projections. Each entry in this list handles one source.",
             "items": {
               "allOf": [
                 {
@@ -5190,7 +5190,7 @@
         "type": "object"
       },
       "io.k8s.api.core.v1.VolumeProjection": {
-        "description": "Projection that may be projected along with other supported volume types",
+        "description": "Projection that may be projected along with other supported volume types. Exactly one of these fields must be set.",
         "properties": {
           "clusterTrustBundle": {
             "allOf": [

api/openapi-spec/v3/apis__apps__v1_openapi.json

@@ -3377,7 +3377,7 @@
             "type": "integer"
           },
           "sources": {
-            "description": "sources is the list of volume projections",
+            "description": "sources is the list of volume projections. Each entry in this list handles one source.",
             "items": {
               "allOf": [
                 {
@@ -4394,7 +4394,7 @@
         "type": "object"
       },
       "io.k8s.api.core.v1.VolumeProjection": {
-        "description": "Projection that may be projected along with other supported volume types",
+        "description": "Projection that may be projected along with other supported volume types. Exactly one of these fields must be set.",
         "properties": {
           "clusterTrustBundle": {
             "allOf": [

api/openapi-spec/v3/apis__batch__v1_openapi.json

@@ -1157,7 +1157,7 @@ func validateProjectionSources(projection *core.ProjectedVolumeSource, projectio
 				allErrs = append(allErrs, ValidateLocalNonReservedPath(source.ServiceAccountToken.Path, fldPath.Child("path"))...)
 			}
 		}
-		if projPath := srcPath.Child("clusterTrustBundlePEM"); source.ClusterTrustBundle != nil {
+		if projPath := srcPath.Child("clusterTrustBundle"); source.ClusterTrustBundle != nil {
 			numSources++
 
 			usingName := source.ClusterTrustBundle.Name != nil
@@ -1221,7 +1221,7 @@ func validateProjectionSources(projection *core.ProjectedVolumeSource, projectio
 			}
 		}
 		if numSources > 1 {
-			allErrs = append(allErrs, field.Forbidden(srcPath, "may not specify more than 1 volume type"))
+			allErrs = append(allErrs, field.Forbidden(srcPath, "may not specify more than 1 volume type per source"))
 		}
 	}
 	return allErrs

pkg/apis/core/validation/validation.go

@@ -1911,7 +1911,8 @@ type ClusterTrustBundleProjection struct {
 
 // Represents a projected volume source
 type ProjectedVolumeSource struct {
-	// sources is the list of volume projections
+	// sources is the list of volume projections. Each entry in this list
+	// handles one source.
 	// +optional
 	// +listType=atomic
 	Sources []VolumeProjection `json:"sources" protobuf:"bytes,1,rep,name=sources"`
@@ -1925,10 +1926,9 @@ type ProjectedVolumeSource struct {
 	DefaultMode *int32 `json:"defaultMode,omitempty" protobuf:"varint,2,opt,name=defaultMode"`
 }
 
-// Projection that may be projected along with other supported volume types
+// Projection that may be projected along with other supported volume types.
+// Exactly one of these fields must be set.
 type VolumeProjection struct {
-	// all types below are the supported types for projection into the same volume
-
 	// secret information about the secret data to project
 	// +optional
 	Secret *SecretProjection `json:"secret,omitempty" protobuf:"bytes,1,opt,name=secret"`