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

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Customizing Istio Metrics This task shows you how to customize the Istio metrics. 25
telemetry
metrics
customize
istio/wg-policies-and-telemetry-maintainers yes

This task shows you how to customize the metrics that Istio generates.

Istio generates telemetry that various dashboards consume to help you visualize your mesh. For example, dashboards that support Istio include:

By default, Istio defines and generates a set of standard metrics (e.g. requests_total), but you can also customize them and create new metrics.

Custom statistics configuration

Istio uses the Envoy proxy to generate metrics and provides its configuration in the EnvoyFilter at [manifests/charts/istio-control/istio-discovery/templates/telemetryv2_{{< istio_version >}}.yaml]({{<github_blob>}}/manifests/charts/istio-control/istio-discovery/templates/telemetryv2_{{< istio_version >}}.yaml).

Configuring custom statistics involves two sections of the EnvoyFilter: definitions and metrics. The definitions section 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. 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.

Before you begin

Install Istio in your cluster and deploy an application. Alternatively, you can set up custom statistics as part of the Istio installation.

The Bookinfo sample application is used as the example application throughout this task.

Enable custom metrics

  1. The default telemetry v2 EnvoyFilter configuration is equivalent to the following installation options:

    {{< text yaml >}} apiVersion: install.istio.io/v1alpha1 kind: IstioOperator spec: values: telemetry: v2: prometheus: configOverride: inboundSidecar: disable_host_header_fallback: false outboundSidecar: disable_host_header_fallback: false gateway: disable_host_header_fallback: true {{< /text >}}

    To customize telemetry v2 metrics, for example, to add request_host 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:

    {{< tip >}} You only need to specify the configuration for the settings that you want to customize. For example, to only customize the sidecar inbound requests_count metric, you can omit the outboundSidecar and gateway sections in the configuration. Unspecified settings will retain the default configuration, equivalent to the explicit settings shown above. {{< /tip >}}

    {{< text bash >}} $ cat < ./custom_metrics.yaml apiVersion: install.istio.io/v1alpha1 kind: IstioOperator spec: values: telemetry: v2: prometheus: configOverride: inboundSidecar: metrics: - name: requests_total dimensions: destination_port: string(destination.port) request_host: request.host outboundSidecar: metrics: - name: requests_total dimensions: destination_port: string(destination.port) request_host: request.host gateway: metrics: - name: requests_total dimensions: destination_port: string(destination.port) request_host: request.host EOF

    istioctl install -f custom_metrics.yaml

    {{< /text >}}

  2. Apply the following annotation to all injected pods with the list of the dimensions to extract into a Prometheus time series using the following command:

    {{< tip >}} This step is needed only if your dimensions are not already in DefaultStatTags list {{< /tip >}}

    {{< text yaml >}} apiVersion: apps/v1 kind: Deployment spec: template: # pod template metadata: annotations: sidecar.istio.io/extraStatTags: destination_port,request_host {{< /text >}}

    To enable extra tags mesh wide, you can add extraStatTags to your mesh config:

    {{< text yaml >}} meshConfig: defaultConfig: extraStatTags: - destination_port - request_host {{< /text >}}

Verify the results

Send traffic to the mesh. For the Bookinfo sample, visit http://$GATEWAY_URL/productpage in your web browser or issue the following command:

{{< text bash >}} $ curl "http://$GATEWAY_URL/productpage" {{< /text >}}

{{< tip >}} $GATEWAY_URL is the value set in the Bookinfo example. {{< /tip >}}

Use the following command to verify that Istio generates the data for your new or modified dimensions:

{{< text bash >}} kubectl exec "(kubectl get pod -l app=productpage -o jsonpath='{.items[0].metadata.name}')" -c istio-proxy -- curl -sS 'localhost:15000/stats/prometheus' | grep istio_requests_total {{< /text >}}

For example, in the output, locate the metric istio_requests_total and verify it contains your new dimension.

{{< tip >}} It might take a short period of time for the proxies to start applying the config. If the metric is not received, you may retry sending requests after a short wait, and look for the metric again. {{< /tip >}}

Use expressions for values

The values in the metric configuration are common expressions, which means you must double-quote strings in JSON, e.g. "'string value'". Unlike Mixer expression language, there is no support for the pipe (|) operator, but you can emulate it with the has or in operator, for example:

{{< text plain >}} has(request.host) ? request.host : "unknown" {{< /text >}}

For more information, see Common Expression Language.

Istio exposes all standard Envoy attributes. Peer metadata is available as attributes upstream_peer for outbound and downstream_peer for inbound with the following fields:

Field Type Value
name string Name of the pod.
namespace string Namespace that the pod runs in.
labels map Workload labels.
owner string Workload owner.
workload_name string Workload name.
platform_metadata map Platform metadata with prefixed keys.
istio_version string Version identifier for the proxy.
mesh_id string Unique identifier for the mesh.
app_containers list<string> List of short names for application containers.
cluster_id string Identifier for the cluster to which this workload belongs.

For example, the expression for the peer app label to be used in an outbound configuration is upstream_peer.labels['app'].value.