Merge pull request #59434 from liggitt/optional-subsets

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Indicate endpoint subsets are an optional field

Fixes #59403 

```release-note
NONE
```

api/openapi-spec/swagger.json

@@ -76162,9 +76162,6 @@
    },
    "io.k8s.api.core.v1.Endpoints": {
     "description": "Endpoints is a collection of endpoints that implement the actual service. Example:\n  Name: \"mysvc\",\n  Subsets: [\n    {\n      Addresses: [{\"ip\": \"10.10.1.1\"}, {\"ip\": \"10.10.2.2\"}],\n      Ports: [{\"name\": \"a\", \"port\": 8675}, {\"name\": \"b\", \"port\": 309}]\n    },\n    {\n      Addresses: [{\"ip\": \"10.10.3.3\"}],\n      Ports: [{\"name\": \"a\", \"port\": 93}, {\"name\": \"b\", \"port\": 76}]\n    },\n ]",
-    "required": [
-     "subsets"
-    ],
     "properties": {
      "apiVersion": {
       "description": "APIVersion defines the versioned schema of this representation of an object. Servers should convert recognized schemas to the latest internal value, and may reject unrecognized values. More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#resources",

api/swagger-spec/v1.json

@@ -18186,9 +18186,6 @@
    "v1.Endpoints": {
     "id": "v1.Endpoints",
     "description": "Endpoints is a collection of endpoints that implement the actual service. Example:\n  Name: \"mysvc\",\n  Subsets: [\n    {\n      Addresses: [{\"ip\": \"10.10.1.1\"}, {\"ip\": \"10.10.2.2\"}],\n      Ports: [{\"name\": \"a\", \"port\": 8675}, {\"name\": \"b\", \"port\": 309}]\n    },\n    {\n      Addresses: [{\"ip\": \"10.10.3.3\"}],\n      Ports: [{\"name\": \"a\", \"port\": 93}, {\"name\": \"b\", \"port\": 76}]\n    },\n ]",
-    "required": [
-     "subsets"
-    ],
     "properties": {
      "kind": {
       "type": "string",

docs/api-reference/v1/definitions.html

@@ -8305,7 +8305,7 @@ Examples:<br>
 <tr>
 <td class="tableblock halign-left valign-top"><p class="tableblock">subsets</p></td>
 <td class="tableblock halign-left valign-top"><p class="tableblock">The set of all endpoints is the union of all subsets. Addresses are placed into subsets according to the IPs they share. A single address with multiple ports, some of which are ready and some of which are not (because they come from different containers) will result in the address being displayed in different subsets for the different ports. No address will appear in both Addresses and NotReadyAddresses in the same subset. Sets of addresses and ports that comprise a service.</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">true</p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock">false</p></td>
 <td class="tableblock halign-left valign-top"><p class="tableblock"><a href="#_v1_endpointsubset">v1.EndpointSubset</a> array</p></td>
 <td class="tableblock halign-left valign-top"></td>
 </tr>

staging/src/k8s.io/api/core/v1/generated.proto

@@ -1004,6 +1004,7 @@ message Endpoints {
   // subsets for the different ports. No address will appear in both Addresses and
   // NotReadyAddresses in the same subset.
   // Sets of addresses and ports that comprise a service.
+  // +optional
   repeated EndpointSubset subsets = 2;
 }
 

staging/src/k8s.io/api/core/v1/types.go

@@ -3723,7 +3723,8 @@ type Endpoints struct {
 	// subsets for the different ports. No address will appear in both Addresses and
 	// NotReadyAddresses in the same subset.
 	// Sets of addresses and ports that comprise a service.
-	Subsets []EndpointSubset `json:"subsets" protobuf:"bytes,2,rep,name=subsets"`
+	// +optional
+	Subsets []EndpointSubset `json:"subsets,omitempty" protobuf:"bytes,2,rep,name=subsets"`
 }
 
 // EndpointSubset is a group of addresses with a common set of ports. The