Update release notes for 5.2.0 (#1101)

Author: vepatel

content/includes/nic/configuration/global-configuration/configmap-resource.md

@@ -80,6 +80,7 @@ For more information, view the [VirtualServer and VirtualServerRoute resources](
 |*proxy-buffering* | Enables or disables [buffering of responses](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffering) from the proxied server. | *True* |  |
 |*proxy-buffers* | Sets the value of the [proxy_buffers](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffers) directive. | Depends on the platform. |  |
 |*proxy-buffer-size* | Sets the value of the [proxy_buffer_size](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffer_size) and [grpc_buffer_size](https://nginx.org/en/docs/http/ngx_http_grpc_module.html#grpc_buffer_size) directives. | Depends on the platform. |  |
+|*proxy-busy-buffers-size* | Sets the value of the [proxy_busy_buffers_size](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_busy_buffers_size) directive. | Depends on the platform. |  |
 |*proxy-max-temp-file-size* | Sets the value of the  [proxy_max_temp_file_size](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_max_temp_file_size) directive. | *1024m* |  |
 |*set-real-ip-from* | Sets the value of the [set_real_ip_from](https://nginx.org/en/docs/http/ngx_http_realip_module.html#set_real_ip_from) directive. | N/A |  |
 |*real-ip-header* | Sets the value of the [real_ip_header](https://nginx.org/en/docs/http/ngx_http_realip_module.html#real_ip_header) directive. | *X-Real-IP* |  |
@@ -198,7 +199,7 @@ If you encounter the error `error [emerg] 13#13: "zone_sync" directive is duplic
 {{<bootstrap-table "table table-striped table-bordered table-responsive">}}
 |ConfigMap Key | Description | Default | Example |
 | ---| ---| ---| --- |
-|*zone-sync* | Enables zone synchronization between NGINX Ingress Controller Pods. This autogenerates a [zone_sync_server](https://nginx.org/en/docs/stream/ngx_stream_zone_sync_module.html#zone_sync_server) and a headless service using the `ReplicaSet` or `DaemonSet` name. Please note that this headless service will be automatically cleaned up when uninstalling via Helm or by removing the value from the ConfigMap. The headless service will need to be manually removed if the `controller.customConfigMap` value is set via Helm or the deployment is uninstalled via Manifests. Each Ingress Controller manages its own headless service.  NGINX Plus Required. | *False* |  |
+|*zone-sync* | Enables zone synchronization between NGINX Ingress Controller Pods. This autogenerates a [zone_sync_server](https://nginx.org/en/docs/stream/ngx_stream_zone_sync_module.html#zone_sync_server) and a headless service using the `ReplicaSet`, `DaemonSet` or `StatefulSet` name. Please note that this headless service will be automatically cleaned up when uninstalling via Helm or by removing the value from the ConfigMap. The headless service will need to be manually removed if the `controller.customConfigMap` value is set via Helm or the deployment is uninstalled via Manifests. Each Ingress Controller manages its own headless service.  NGINX Plus Required. | *False* |  |
 |*zone-sync-port* | Specifies the optional port on which NGINX Ingress Controller listens for zone sync traffic. NGINX Plus & `zone-sync` Required. | *12345* |  |
 |*zone-sync-resolver-addresses* | Configures optional addresses used in the [resolver](https://nginx.org/en/docs/http/ngx_http_core_module.html#resolver) directive for zone-sync. This field takes a comma separated list of addresses. NGINX Plus & `zone-sync` Required | `kube-dns.kube-system.svc.cluster.local` |  |
 |*zone-sync-resolver-ipv6* | Configures whether the optional [resolver](https://nginx.org/en/docs/http/ngx_http_core_module.html#resolver) directive for zone-sync will look up IPv6 addresses. NGINX Plus & `zone-sync` Required | `true` |  |

content/includes/nic/configuration/ingress-resources/advanced-configuration-with-annotations.md

@@ -108,6 +108,7 @@ The table below summarizes the available annotations.
 | *nginx.org/proxy-buffering* | *proxy-buffering* | Enables or disables [buffering of responses](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffering) from the proxied server. | *True* |  |
 | *nginx.org/proxy-buffers* | *proxy-buffers* | Sets the value of the [proxy_buffers](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffers) directive. | Depends on the platform. |  |
 | *nginx.org/proxy-buffer-size* | *proxy-buffer-size* | Sets the value of the [proxy_buffer_size](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffer_size) and [grpc_buffer_size](https://nginx.org/en/docs/http/ngx_http_grpc_module.html#grpc_buffer_size) directives. | Depends on the platform. |  |
+| *nginx.org/proxy-busy-buffers-size* | *proxy-busy-buffers-size* | Sets the value of the [proxy_busy_buffers_size](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_busy_buffers_size) directive. | Depends on the platform. |  |
 | *nginx.org/proxy-max-temp-file-size* | *proxy-max-temp-file-size* | Sets the value of the  [proxy_max_temp_file_size](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_max_temp_file_size) directive. | *1024m* |  |
 | *nginx.org/server-tokens* | *server-tokens* | Enables or disables the [server_tokens](https://nginx.org/en/docs/http/ngx_http_core_module.html#server_tokens) directive. Additionally, with the NGINX Plus, you can specify a custom string value, including the empty string value, which disables the emission of the “Server” field. | *True* |  |
 | *nginx.org/path-regex* | N/A | Enables regular expression modifiers for Ingress path parameter. This translates to the NGINX [location](https://nginx.org/en/docs/http/ngx_http_core_module.html#location) directive. You can specify one of these values: "case_sensitive", "case_insensitive", or "exact". The annotation is applied to the entire Ingress resource and its paths. While using Master and Minion Ingresses i.e. Mergeable Ingresses, this annotation can be specified on Minion types. The `path-regex` annotation specified on Master is ignored, and has no effect on paths defined on Minions.   | N/A |  [path-regex](https://github.com/nginx/kubernetes-ingress/tree/v{{< nic-version >}}/examples/ingress-resources/path-regex) |

content/includes/nic/configuration/security.md

@@ -53,10 +53,12 @@ The block below shows the code you will look for:
 #      volumes:
 #      - name: nginx-etc
 #        emptyDir: {}
-#      - name: nginx-cache
-#        emptyDir: {}
+#      - name: nginx-cache  # do not set this value in statefulset if volumeclaimtemplate is set
+#        emptyDir: {}       # do not set this value in statefulset if volumeclaimtemplate is set
 #      - name: nginx-lib
 #        emptyDir: {}
+#      - name: nginx-lib-state
+#        emptyDir: {}
 #      - name: nginx-log
 #        emptyDir: {}
 .
@@ -73,6 +75,8 @@ The block below shows the code you will look for:
 #          name: nginx-cache
 #        - mountPath: /var/lib/nginx
 #          name: nginx-lib
+#        - mountPath: /var/lib/nginx/state
+#          name: nginx-lib-state
 #        - mountPath: /var/log/nginx
 #          name: nginx-log
 ```

content/includes/nic/configuration/virtualserver-and-virtualserverroute-resources.md

@@ -371,6 +371,7 @@ tls:
 |``buffering`` | Enables buffering of responses from the upstream server. See the [proxy_buffering](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffering) directive. The default is set in the ``proxy-buffering`` ConfigMap key. | ``boolean`` | No |
 |``buffers`` | Configures the buffers used for reading a response from the upstream server for a single connection. | [buffers](#upstreambuffers) | No |
 |``buffer-size`` | Sets the size of the buffer used for reading the first part of a response received from the upstream server. See the [proxy_buffer_size](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffer_size) directive. The default is set in the ``proxy-buffer-size`` ConfigMap key. | ``string`` | No |
+|``busy-buffer-size`` | Sets the size of the buffer used for reading a response from the upstream server when the response is larger than the ``buffer-size``. See the [proxy_busy_buffers_size](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_busy_buffers_size) directive. The default is set in the ``proxy-busy-buffers-size`` ConfigMap key. | ``string`` | No |
 |``ntlm`` | Allows proxying requests with NTLM Authentication. See the [ntlm](https://nginx.org/en/docs/http/ngx_http_upstream_module.html#ntlm) directive. In order for NTLM authentication to work, it is necessary to enable keepalive connections to upstream servers using the ``keepalive`` field. Note: this feature is supported only in NGINX Plus.| ``boolean`` | No |
 |``type`` |The type of the upstream. Supported values are ``http`` and ``grpc``. The default is ``http``. For gRPC, it is necessary to enable HTTP/2 in the [ConfigMap](/nginx-ingress-controller/configuration/global-configuration/configmap-resource/#listeners) and configure TLS termination in the VirtualServer. | ``string`` | No |
 |``backup`` | The name of the backup service of type [ExternalName](https://kubernetes.io/docs/concepts/services-networking/service/#externalname). This will be used when the primary servers are unavailable. Note: The parameter cannot be used along with the ``random`` , ``hash`` or ``ip_hash`` load balancing methods. | ``string`` | No |

content/includes/nic/installation/deploy-controller.md

@@ -6,5 +6,6 @@ You have two options for deploying NGINX Ingress Controller:
 
 - **Deployment**. Choose this method for the flexibility to dynamically change the number of NGINX Ingress Controller replicas.
 - **DaemonSet**. Choose this method if you want NGINX Ingress Controller to run on all nodes or a subset of nodes.
+- **StatefulSet**. Choose this method when you need stable, persistent storage and ordered deployment/scaling for your NGINX Ingress Controller pods.
 
 Before you start, update the [command-line arguments]({{< ref "/nic/configuration/global-configuration/command-line-arguments.md" >}}) for the NGINX Ingress Controller container in the relevant manifest file to meet your specific requirements.

content/includes/nic/installation/manifests/statefulset.md

@@ -0,0 +1,25 @@
+---
+nd-docs: DOCS-000
+---
+
+For additional context on managing containers using Kubernetes StatefulSets, refer to the official Kubernetes [StatefulSets](https://kubernetes.io/docs/concepts/workloads/controllers/statefulset/) documentation.
+
+When you deploy NGINX Ingress Controller as a StatefulSet, Kubernetes creates pods with stable network identities and persistent storage.
+
+- For NGINX, run:
+
+    ```shell
+    kubectl apply -f deployments/stateful-set/nginx-ingress.yaml
+    ```
+
+- For NGINX Plus, run:
+
+    ```shell
+    kubectl apply -f deployments/stateful-set/nginx-plus-ingress.yaml
+    ```
+
+    Update the `nginx-plus-ingress.yaml` file to include your chosen image from the F5 Container registry or your custom container image.
+
+{{< call-out "note" >}}
+StatefulSets include persistent volume claims for nginx cache storage via `volumeClaimTemplates`. You may need to configure a StorageClass in your cluster or modify the volumeClaimTemplates section in the manifest to match your storage requirements. Other volumes (like those needed for App Protect modules) are configured in the regular `volumes` section, not in volumeClaimTemplates. 
+{{< /call-out >}}

content/nic/configuration/global-configuration/command-line-arguments.md

@@ -658,6 +658,20 @@ The default value is `false`.
 
 ---
 
+### -enable-directive-autoadjust
+
+Automatically adjusts NGINX buffer directives to prevent configuration errors.
+
+The default value is `false`.
+
+When enabled, the controller automatically adjusts `proxy_buffers`, `proxy_buffer_size`, and `proxy_busy_buffers_size` to ensure they work together properly and NGINX can start successfully.
+
+More explanation about this feature can be found in the guide [here](<ref "/nic/installation/configuration/proxy-buffers-configuration.md">).
+
+<a name="cmdoption-enable-directive-autoadjust"></a>
+
+---
+
 ### -enable-telemetry-reporting
 
 Enable gathering and reporting of software telemetry.

content/nic/configuration/global-configuration/configmap-resource.md

@@ -75,6 +75,7 @@ For more information, view the [VirtualServer and VirtualServerRoute resources](
 |*proxy-buffering* | Enables or disables [buffering of responses](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffering) from the proxied server. | *True* |  |
 |*proxy-buffers* | Sets the value of the [proxy_buffers](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffers) directive. | Depends on the platform. |  |
 |*proxy-buffer-size* | Sets the value of the [proxy_buffer_size](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffer_size) and [grpc_buffer_size](https://nginx.org/en/docs/http/ngx_http_grpc_module.html#grpc_buffer_size) directives. | Depends on the platform. |  |
+|*proxy-busy-buffers-size* | Sets the value of the [proxy_busy_buffers_size](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_busy_buffers_size) directive. | Depends on the platform. |  |
 |*proxy-max-temp-file-size* | Sets the value of the  [proxy_max_temp_file_size](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_max_temp_file_size) directive. | *1024m* |  |
 |*set-real-ip-from* | Sets the value of the [set_real_ip_from](https://nginx.org/en/docs/http/ngx_http_realip_module.html#set_real_ip_from) directive. | N/A |  |
 |*real-ip-header* | Sets the value of the [real_ip_header](https://nginx.org/en/docs/http/ngx_http_realip_module.html#real_ip_header) directive. | *X-Real-IP* |  |
@@ -171,7 +172,7 @@ If you encounter the error `error [emerg] 13#13: "zone_sync" directive is duplic
 
 |ConfigMap Key | Description | Default |
 | ---| ---| ---| 
-|*zone-sync* | Enables zone synchronization between NGINX Ingress Controller Pods. This autogenerates a [zone_sync_server](https://nginx.org/en/docs/stream/ngx_stream_zone_sync_module.html#zone_sync_server) and a headless service using the `ReplicaSet` or `DaemonSet` name. Please note that this headless service will be automatically cleaned up when uninstalling via Helm or by removing the value from the ConfigMap. The headless service will need to be manually removed if the `controller.customConfigMap` value is set via Helm or the deployment is uninstalled via Manifests. Each Ingress Controller manages its own headless service.  NGINX Plus Required. | *False* |
+|*zone-sync* | Enables zone synchronization between NGINX Ingress Controller Pods. This autogenerates a [zone_sync_server](https://nginx.org/en/docs/stream/ngx_stream_zone_sync_module.html#zone_sync_server) and a headless service using the `ReplicaSet`, `DaemonSet` or `StatefulSet` name. Please note that this headless service will be automatically cleaned up when uninstalling via Helm or by removing the value from the ConfigMap. The headless service will need to be manually removed if the `controller.customConfigMap` value is set via Helm or the deployment is uninstalled via Manifests. Each Ingress Controller manages its own headless service.  NGINX Plus Required. | *False* |
 |*zone-sync-port* | Specifies the optional port on which NGINX Ingress Controller listens for zone sync traffic. NGINX Plus & `zone-sync` Required. | *12345* |
 |*zone-sync-resolver-addresses* | Configures optional addresses used in the [resolver](https://nginx.org/en/docs/http/ngx_http_core_module.html#resolver) directive for zone-sync. This field takes a comma separated list of addresses. NGINX Plus & `zone-sync` Required | `kube-dns.kube-system.svc.cluster.local` |
 |*zone-sync-resolver-ipv6* | Configures whether the optional [resolver](https://nginx.org/en/docs/http/ngx_http_core_module.html#resolver) directive for zone-sync will look up IPv6 addresses. NGINX Plus & `zone-sync` Required | `true` |

content/nic/configuration/ingress-resources/advanced-configuration-with-annotations.md

@@ -108,6 +108,7 @@ The table below summarizes the available annotations.
 | *nginx.org/proxy-buffering* | *proxy-buffering* | Enables or disables [buffering of responses](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffering) from the proxied server. | *True* |  |
 | *nginx.org/proxy-buffers* | *proxy-buffers* | Sets the value of the [proxy_buffers](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffers) directive. | Depends on the platform. |  |
 | *nginx.org/proxy-buffer-size* | *proxy-buffer-size* | Sets the value of the [proxy_buffer_size](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffer_size) and [grpc_buffer_size](https://nginx.org/en/docs/http/ngx_http_grpc_module.html#grpc_buffer_size) directives. | Depends on the platform. |  |
+| *nginx.org/proxy-busy-buffers-size* | *proxy-busy-buffers-size* | Sets the value of the [proxy_busy_buffers_size](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_busy_buffers_size) directive. | Depends on the platform. |  |
 | *nginx.org/proxy-max-temp-file-size* | *proxy-max-temp-file-size* | Sets the value of the  [proxy_max_temp_file_size](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_max_temp_file_size) directive. | *1024m* |  |
 | *nginx.org/server-tokens* | *server-tokens* | Enables or disables the [server_tokens](https://nginx.org/en/docs/http/ngx_http_core_module.html#server_tokens) directive. Additionally, with the NGINX Plus, you can specify a custom string value, including the empty string value, which disables the emission of the “Server” field. | *True* |  |
 | *nginx.org/path-regex* | N/A | Enables regular expression modifiers for Ingress path parameter. This translates to the NGINX [location](https://nginx.org/en/docs/http/ngx_http_core_module.html#location) directive. You can specify one of these values: "case_sensitive", "case_insensitive", or "exact". The annotation is applied to the entire Ingress resource and its paths. While using Master and Minion Ingresses i.e. Mergeable Ingresses, this annotation can be specified on Minion types. The `path-regex` annotation specified on Master is ignored, and has no effect on paths defined on Minions.   | N/A |  [path-regex](https://github.com/nginx/kubernetes-ingress/tree/v{{< nic-version >}}/examples/ingress-resources/path-regex) |