Merge pull request #24874 from janosi/mixedprotocollb

Document the support of mixed protocol values in the LoadBalancer type of Services

content/en/docs/concepts/services-networking/service.md

@@ -578,10 +578,6 @@ status:
 
 Traffic from the external load balancer is directed at the backend Pods. The cloud provider decides how it is load balanced.
 
-For LoadBalancer type of Services, when there is more than one port defined, all
-ports must have the same protocol, and the protocol must be one which is supported
-by the cloud provider.
-
 Some cloud providers allow you to specify the `loadBalancerIP`. In those cases, the load-balancer is created
 with the user-specified `loadBalancerIP`. If the `loadBalancerIP` field is not specified,
 the loadBalancer is set up with an ephemeral IP address. If you specify a `loadBalancerIP`
@@ -599,6 +595,23 @@ Specify the assigned IP address as loadBalancerIP. Ensure that you have updated
 
 {{< /note >}}
 
+#### Load balancers with mixed protocol types
+
+{{< feature-state for_k8s_version="v1.20" state="alpha" >}}
+
+By default, for LoadBalancer type of Services, when there is more than one port defined, all
+ports must have the same protocol, and the protocol must be one which is supported
+by the cloud provider.
+
+If the feature gate `MixedProtocolLBService` is enabled for the kube-apiserver it is allowed to use different protocols when there is more than one port defined. 
+
+{{< note >}}
+
+The set of protocols that can be used for LoadBalancer type of Services is still defined by the cloud provider.
+
+{{< /note >}}
+
+
 #### Internal load balancer
 
 In a mixed environment it is sometimes necessary to route traffic from Services inside the same

content/en/docs/reference/command-line-tools-reference/feature-gates.md

@@ -125,6 +125,7 @@ different Kubernetes components.
 | `LocalStorageCapacityIsolation` | `false` | Alpha | 1.7 | 1.9 |
 | `LocalStorageCapacityIsolation` | `true` | Beta | 1.10 | |
 | `LocalStorageCapacityIsolationFSQuotaMonitoring` | `false` | Alpha | 1.15 | |
+| `MixedProtocolLBService` | `false` | Alpha | 1.20 | |
 | `MountContainers` | `false` | Alpha | 1.9 | |
 | `NodeDisruptionExclusion` | `false` | Alpha | 1.16 | 1.18 |
 | `NodeDisruptionExclusion` | `true` | Beta | 1.19 | |
@@ -500,6 +501,7 @@ Each feature gate is designed for enabling/disabling a specific feature:
 - `LegacyNodeRoleBehavior`: When disabled, legacy behavior in service load balancers and node disruption will ignore the `node-role.kubernetes.io/master` label in favor of the feature-specific labels provided by `NodeDisruptionExclusion` and `ServiceNodeExclusion`.
 - `LocalStorageCapacityIsolation`: Enable the consumption of [local ephemeral storage](/docs/concepts/configuration/manage-resources-containers/) and also the `sizeLimit` property of an [emptyDir volume](/docs/concepts/storage/volumes/#emptydir).
 - `LocalStorageCapacityIsolationFSQuotaMonitoring`: When `LocalStorageCapacityIsolation` is enabled for [local ephemeral storage](/docs/concepts/configuration/manage-resources-containers/) and the backing filesystem for [emptyDir volumes](/docs/concepts/storage/volumes/#emptydir) supports project quotas and they are enabled, use project quotas to monitor [emptyDir volume](/docs/concepts/storage/volumes/#emptydir) storage consumption rather than filesystem walk for better performance and accuracy.
+- `MixedProtocolLBService`: Enable using different protocols in the same LoadBalancer type Service instance.
 - `MountContainers`: Enable using utility containers on host as the volume mounter.
 - `MountPropagation`: Enable sharing volume mounted by one container to other containers or pods.
   For more details, please see [mount propagation](/docs/concepts/storage/volumes/#mount-propagation).