Clean up metric customization to get rid of envoyfilter based text editing (#7952)

* clean up metric customization to get rid of envoy filter based text
editing

* lint

* lint

* Apply suggestions from code review

Co-authored-by: Frank Budinsky <frankb@ca.ibm.com>

* fix lint

Co-authored-by: Frank Budinsky <frankb@ca.ibm.com>

content/en/docs/tasks/observability/metrics/customize-metrics/index.md

@@ -23,7 +23,7 @@ By default, Istio defines and generates a set of standard metrics (e.g.
 
 Istio uses the Envoy proxy to generate metrics and provides its configuration in
 the `EnvoyFilter` at
-[`manifests/charts/istio-control/istio-discovery/templates/telemetryv2_1.6.yaml`]({{<github_blob>}}/manifests/charts/istio-control/istio-discovery/templates/telemetryv2_1.6.yaml).
+[`manifests/charts/istio-control/istio-discovery/templates/telemetryv2_1.7.yaml`]({{<github_blob>}}/manifests/charts/istio-control/istio-discovery/templates/telemetryv2_1.7.yaml).
 
 Configuring custom statistics involves two sections of the
 `EnvoyFilter`: `definitions` and `metrics`. The `definitions` section
@@ -31,7 +31,10 @@ supports creating new metrics by name, the expected value expression, and the
 metric type (`counter`, `gauge`, and `histogram`). The `metrics` section
 provides values for the metric dimensions as expressions, and allows you to
 remove or override the existing metric dimensions. You can modify the standard
-metric definitions using `tags_to_remove` or by re-defining a dimension.
+metric definitions using `tags_to_remove` or by re-defining a dimension. These
+configuration settings are also exposed as istioctl installation options, which
+allow you to customize different metrics for gateways and sidecars as well as
+for the inbound or outbound direction.
 
 For more information, see [Stats Config reference](/docs/reference/config/proxy_extensions/stats/).
 
@@ -43,63 +46,75 @@ installation.
 
 ## Enable custom metrics
 
-Edit the `EnvoyFilter` to add or modify dimensions and metrics. Then, add
+1. The default telemetry v2 `EnvoyFilter` configuration is equivalent to the following installation options:
-annotations to all the Istio-enabled pods to extract the new or modified
-dimensions.
 
-1. Find the `stats-filter-1.6` `EnvoyFilter` resource from the `istio-system`
+    {{< text yaml >}}
-   namespace, using the following command:
+    apiVersion: install.istio.io/v1alpha1
-
+    kind: IstioOperator
-    {{< text bash >}}
+    spec:
-    $ kubectl -n istio-system get envoyfilter | grep ^stats-filter-1.6
+      value:
-    stats-filter-1.6                    2d
+        telemetry:
+          v2:
+            prometheus:
+              configOverride:
+                inboundSidecar:
+                  debug: false
+                  stat_prefix: istio
+                outboundSidecar:
+                  debug: false
+                  stat_prefix: istio
+                gateway:
+                  debug: false
+                  stat_prefix: istio
+                  disable_host_header_fallback: true
     {{< /text >}}
 
-1. Create a local file system copy of the `EnvoyFilter` configuration, using the
+    To customize telemetry v2 metrics, for example, to add `request_host`
-   following command:
+    and `destination_port` dimensions to the `requests_total` metric emitted by both
+    gateways and sidecars in the inbound and outbound direction, change the installation
+    options as follows:
 
-    {{< text bash >}}
+    {{< tip >}}
-    $ kubectl -n istio-system get envoyfilter stats-filter-1.6 -o yaml > stats-filter-1.6.yaml
+    You only need to specify the configuration for the settings that you want to customize.
-    {{< /text >}}
+    For example, to only customize the sidecar inbound `requests_count` metric, you can omit
+    the `outboundSidecar` and `inboundSidecar` sections in the configuration. Unspecified
+    settings will retain the default configuration, equivalent to the explicit settings shown above.
+    {{< /tip >}}
 
-1. Open `stats-filter-1.6.yaml` with a text editor and locate the
+    {{< text yaml >}}
-   `envoy.wasm.stats` extension configuration. The default configuration is in
+    apiVersion: install.istio.io/v1alpha1
-   the `configuration` section and looks like this example:
+    kind: IstioOperator
-
+    spec:
-    {{< text json >}}
+      value:
-    {
+        telemetry:
-    "debug": "false",
+          v2:
-    "stat_prefix": "istio"
+            prometheus:
-    }
+              configOverride:
-    {{< /text >}}
+                inboundSidecar:
-
+                  debug: false
-1. Edit `stats-filter-1.6.yaml` and modify the configuration section for each
+                  stat_prefix: istio
-   instance of the extension configuration. For example, to add
+                  metrics:
-   `destination_port` and `request_host` dimensions to the standard
+                    - name: requests_total
-   `requests_total` metric, change the configuration section to look like the
+                      dimensions:
-   following. Istio automatically prefixes all metric names with `istio_`, so
+                        destination_port: string(destination.port)
-   omit the prefix from the name field in the metric specification.
+                        request_host: request.host
-
+                outboundSidecar:
-    {{< text json >}}
+                  debug: false
-    {
+                  stat_prefix: istio
-        "debug": "false",
+                  metrics:
-        "stat_prefix": "istio",
+                    - name: requests_total
-        "metrics": [
+                      dimensions:
-            {
+                        destination_port: string(destination.port)
-                "name": "requests_total",
+                        request_host: request.host
-                "dimensions": {
+                gateway:
-                    "destination_port": "string(destination.port)",
+                  debug: false
-                    "request_host": "request.host"
+                  stat_prefix: istio
-                }
+                  disable_host_header_fallback: true
-            }
+                  metrics:
-        ]
+                    - name: requests_total
-    }
+                      dimensions:
-    {{< /text >}}
+                        destination_port: string(destination.port)
-
+                        request_host: request.host
-1. Save `stats-filter-1.6.yaml` and then apply the configuration using the following command:
-
-    {{< text bash >}}
-    $ kubectl -n istio-system apply -f stats-filter-1.6.yaml
     {{< /text >}}
 
 1. Apply the following annotation to all injected pods with the list of the