blog: GAMMA stable (#15061)

* blog: GAMMA stable

This adds a blog post for GW 1.1 mesh support

FYI: https://kubernetes.io/blog/2024/05/09/gateway-api-v1-1 exists.

* Address Craig's comments

* sort

.spelling

@@ -1157,9 +1157,13 @@ UTF-8
 v0.14.0
 v0.8.0
 v1
+v1.0
+v1.1
+v1.19
 v1.2.
 v1.21
 v1.21.0
+v1.22
 v1.26
 v1.27
 v1.28

content/en/blog/2024/gateway-mesh-ga/index.md

@@ -0,0 +1,98 @@
+---
+title: "Gateway API Mesh Support Promoted To Stable"
+description: The next-generation Kubernetes traffic routing APIs are now Generally Available for service mesh use cases. 
+publishdate: 2024-05-13
+attribution: John Howard - solo.io
+keywords: [istio, traffic, API]
+target_release: 1.22
+---
+
+We are thrilled to announce that Service Mesh support in the [Gateway API](https://gateway-api.sigs.k8s.io/) is now officially "Stable"!
+With this release (part of Gateway API v1.1 and Istio v1.22), users can make use of the next-generation traffic management APIs for both ingress ("north-south") and service mesh use cases ("east-west").
+
+## What is the Gateway API?
+
+The Gateway API is a collection of APIs that are part of Kubernetes, focusing on traffic routing and management.
+The APIs are inspired by, and serve many of the same roles as, Kubernetes' `Ingress` and Istio's `VirtualService` and `Gateway` APIs.
+
+These APIs have been under development both in Istio, as well as with [broad collaboration](https://gateway-api.sigs.k8s.io/implementations/), since 2020, and have come a long way since then.
+While the API initially targeted only serving ingress use cases (which went GA [last year](https://kubernetes.io/blog/2023/10/31/gateway-api-ga/)), we had always envisioned allowing the same APIs to be used for traffic *within* a cluster as well.
+
+With this release, that vision is made a reality: Istio users can use the same routing API for all of their traffic!
+
+## Getting started
+
+Throughout the Istio documentation, all of our examples have been updated to show how to use the Gateway API, so explore some of the [tasks](/docs/tasks/traffic-management/) to gain a deeper understanding.
+
+Using Gateway API for service mesh should feel familiar both to users already using Gateway API for ingress, and users using `VirtualService` for service mesh today.
+
+* Compared to Gateway API for ingress, routes target a `Service` instead of a `Gateway`.
+* Compared to `VirtualService`, where routes associate with a set of `hosts`, routes target a `Service`.
+
+Here is a simple example, which demonstrates routing requests to two different versions of a `Service` based on the request header:
+
+{{< text yaml >}}
+apiVersion: gateway.networking.k8s.io/v1
+kind: HTTPRoute
+metadata:
+  name: reviews
+spec:
+  parentRefs:
+  - group: ""
+    kind: Service
+    name: reviews
+    port: 9080
+  rules:
+  - matches:
+    - headers:
+      - name: my-favorite-service-mesh
+        value: istio
+    filters:
+    - type: RequestHeaderModifier
+      requestHeaderModifier:
+      add:
+        - name: hello
+          value: world
+    backendRefs:
+    - name: reviews-v2
+      port: 9080
+  - backendRefs:
+    - name: reviews-v1
+      port: 9080
+{{< /text >}}
+
+Breaking this down, we have a few parts:
+* First, we identify what routes we should match.
+  By attaching our route to the `reviews` Service, we will apply this routing configuration to all requests that were originally targeting `reviews`.
+* Next, `matches` configures criteria for selecting which traffic this route should handle.
+* Optionally, we can modify the request. Here, we add a header.
+* Finally, we select a destination for the request. In this example, we are picking between two versions of our application.
+
+For more details, see [Istio's traffic routing internals](/docs/ops/configuration/traffic-management/traffic-routing/) and [Gateway API's Service documentation](https://gateway-api.sigs.k8s.io/mesh/service-facets/).
+
+## Which API should I use?
+
+With overlapping responsibilities (and names!), picking which APIs to use can be a bit confusing.
+
+Here is the breakdown:
+
+| API Name     | Object Types                                                                                                                          | Status                            | Recommendation                                                             |
+|--------------|---------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------|----------------------------------------------------------------------------|
+| Gateway APIs | [HTTPRoute](https://gateway-api.sigs.k8s.io/api-types/httproute/), [Gateway](https://gateway-api.sigs.k8s.io/api-types/gateway/), ... | Stable in Gateway API v1.0 (2023) | Use for new deployments, in particular with [ambient mode](/docs/ambient/) |
+| Istio APIs   | [Virtual Service](/docs/reference/config/networking/virtual-service/), [Gateway](/docs/reference/config/networking/gateway/)          | `v1` in Istio 1.22 (2024)         | Use for existing deployments, or where advanced features are needed        |
+| Ingress API  | [Ingress](https://kubernetes.io/docs/concepts/services-networking/ingress)                                                            | Stable in Kubernetes v1.19 (2020) | Use only for legacy deployments                                            |
+
+You may wonder, given the above, why the Istio APIs were [promoted to `v1`](/blog/2024/v1-apis) concurrently?
+This was part of an effort to accurate categorize the *stability* of the APIs.
+While we view Gateway API as the future (and present!) of traffic routing APIs, our existing APIs are here to stay for the long run, with full compatibility.
+This mirrors Kubernetes' approach with [`Ingress`](https://kubernetes.io/docs/concepts/services-networking/ingress), which was promoted to `v1` while directing future work towards the Gateway API.
+
+## Community
+
+This stability graduation represents the culmination of countless hours of work and collaboration across the project.
+It is incredible to look at the [list of organizations](https://gateway-api.sigs.k8s.io/implementations/) involved in the API and consider back at how far we have come.
+
+A special thanks goes out to my [co-leads on the effort](https://gateway-api.sigs.k8s.io/mesh/gamma/): Flynn, Keith Mattix, and Mike Morris, as well as the countless others involved.
+
+Interested in getting involved, or even just providing feedback?
+Check out Istio's [community page](/get-involved/) or the Gateway API [contributing guide](https://gateway-api.sigs.k8s.io/contributing/)!