--- title: Collecting Metrics for TCP services description: This task shows you how to configure Istio to collect metrics for TCP services. weight: 25 --- This task shows how to configure Istio to automatically gather telemetry for TCP services in a mesh. At the end of this task, a new metric will be enabled for calls to a TCP service within your mesh. The [Bookinfo](/docs/guides/bookinfo/) sample application is used as the example application throughout this task. ## Before you begin * [Install Istio](/docs/setup/) in your cluster and deploy an application. * This task assumes that the Bookinfo sample will be deployed in the `default` namespace. If you use a different namespace, you will need to update the example configuration and commands. ## Collecting new telemetry data 1. Create a new YAML file to hold configuration for the new metrics that Istio will generate and collect automatically. Save the following as `tcp_telemetry.yaml`: ```yaml # Configuration for a metric measuring bytes sent from a server # to a client apiVersion: "config.istio.io/v1alpha2" kind: metric metadata: name: mongosentbytes namespace: default spec: value: connection.sent.bytes | 0 # uses a TCP-specific attribute dimensions: source_service: source.service | "unknown" source_version: source.labels["version"] | "unknown" destination_version: destination.labels["version"] | "unknown" monitoredResourceType: '"UNSPECIFIED"' --- # Configuration for a metric measuring bytes sent from a client # to a server apiVersion: "config.istio.io/v1alpha2" kind: metric metadata: name: mongoreceivedbytes namespace: default spec: value: connection.received.bytes | 0 # uses a TCP-specific attribute dimensions: source_service: source.service | "unknown" source_version: source.labels["version"] | "unknown" destination_version: destination.labels["version"] | "unknown" monitoredResourceType: '"UNSPECIFIED"' --- # Configuration for a Prometheus handler apiVersion: "config.istio.io/v1alpha2" kind: prometheus metadata: name: mongohandler namespace: default spec: metrics: - name: mongo_sent_bytes # Prometheus metric name instance_name: mongosentbytes.metric.default # Mixer instance name (fully-qualified) kind: COUNTER label_names: - source_service - source_version - destination_version - name: mongo_received_bytes # Prometheus metric name instance_name: mongoreceivedbytes.metric.default # Mixer instance name (fully-qualified) kind: COUNTER label_names: - source_service - source_version - destination_version --- # Rule to send metric instances to a Prometheus handler apiVersion: "config.istio.io/v1alpha2" kind: rule metadata: name: mongoprom namespace: default spec: match: context.protocol == "tcp" && destination.service == "mongodb.default.svc.cluster.local" actions: - handler: mongohandler.prometheus instances: - mongoreceivedbytes.metric - mongosentbytes.metric ``` 1. Push the new configuration. ```command $ istioctl create -f tcp_telemetry.yaml Created config metric/default/mongosentbytes at revision 3852843 Created config metric/default/mongoreceivedbytes at revision 3852844 Created config prometheus/default/mongohandler at revision 3852845 Created config rule/default/mongoprom at revision 3852846 ``` 1. Setup Bookinfo to use MongoDB. 1. Install `v2` of the `ratings` service. If you are using a cluster with automatic sidecar injection enabled, simply deploy the services using `kubectl`: ```command $ kubectl apply -f @samples/bookinfo/kube/bookinfo-ratings-v2.yaml@ ``` If you are using manual sidecar injection, use the following command instead: ```command $ kubectl apply -f <(istioctl kube-inject -f @samples/bookinfo/kube/bookinfo-ratings-v2.yaml@) deployment "ratings-v2" configured ``` 1. Install the `mongodb` service: If you are using a cluster with automatic sidecar injection enabled, simply deploy the services using `kubectl`: ```command $ kubectl apply -f @samples/bookinfo/kube/bookinfo-db.yaml@ ``` If you are using manual sidecar injection, use the following command instead: ```command $ kubectl apply -f <(istioctl kube-inject -f @samples/bookinfo/kube/bookinfo-db.yaml@) service "mongodb" configured deployment "mongodb-v1" configured ``` 1. Add routing rules to send traffic to `v2` of the `ratings` service: ```command $ istioctl create -f @samples/bookinfo/kube/route-rule-ratings-db.yaml@ Created config route-rule//ratings-test-v2 at revision 7216403 Created config route-rule//reviews-test-ratings-v2 at revision 7216404 ``` 1. Send traffic to the sample application. For the Bookinfo sample, visit `http://$GATEWAY_URL/productpage` in your web browser or issue the following command: ```command $ curl http://$GATEWAY_URL/productpage ``` 1. Verify that the new metric values are being generated and collected. In a Kubernetes environment, setup port-forwarding for Prometheus by executing the following command: ```command $ kubectl -n istio-system port-forward $(kubectl -n istio-system get pod -l app=prometheus -o jsonpath='{.items[0].metadata.name}') 9090:9090 & ``` View values for the new metric via the [Prometheus UI](http://localhost:9090/graph#%5B%7B%22range_input%22%3A%221h%22%2C%22expr%22%3A%22istio_mongo_received_bytes%22%2C%22tab%22%3A1%7D%5D). The provided link opens the Prometheus UI and executes a query for values of the `istio_mongo_received_bytes` metric. The table displayed in the **Console** tab includes entries similar to: ```plain istio_mongo_received_bytes{destination_version="v1",instance="istio-mixer.istio-system:42422",job="istio-mesh",source_service="ratings.default.svc.cluster.local",source_version="v2"} 2317 ``` > Istio also collects protocol-specific statistics for MongoDB. For > example, the value of total OP_QUERY messages sent from the `ratings` service > is collected in the following metric: > `envoy_mongo_mongo_collection_ratings_query_total` (click > (click [here](http://localhost:9090/graph#%5B%7B%22range_input%22%3A%221h%22%2C%22expr%22%3A%22envoy_mongo_mongo_collection_ratings_query_total%22%2C%22tab%22%3A1%7D%5D) > to execute the query). ## Understanding TCP telemetry collection In this task, you added Istio configuration that instructed Mixer to automatically generate and report a new metric for all traffic to a TCP service within the mesh. Similar to the [Collecting Metrics and Logs](/docs/tasks/telemetry/metrics-logs/) Task, the new configuration consisted of _instances_, a _handler_, and a _rule_. Please see that Task for a complete description of the components of metric collection. Metrics collection for TCP services differs only in the limited set of attributes that are available for use in _instances_. ### TCP Attributes Several TCP-specific attributes enable TCP policy and control within Istio. These attributes are generated by server-side Envoy proxies. They are forwarded to Mixer at connection establishment, and forwarded periodically when connection is alive (periodical report), and forwarded at connection close (final report). The default interval for periodical report is 10 seconds, and it should be at least 1 second. Additionally, context attributes provide the ability to distinguish between `http` and `tcp` protocols within policies. {{< image width="100%" ratio="192.50%" link="../img/istio-tcp-attribute-flow.svg" alt="Attribute Generation Flow for TCP Services in an Istio Mesh." caption="TCP Attribute Flow" >}} ## Cleanup * Remove the new telemetry configuration: ```command $ istioctl delete -f tcp_telemetry.yaml ``` * Remove the `port-forward` process: ```command $ killall kubectl ``` * If you are not planning to explore any follow-on tasks, refer to the [Bookinfo cleanup](/docs/guides/bookinfo/#cleanup) instructions to shutdown the application. ## What's next * Learn more about [Mixer](/docs/concepts/policies-and-telemetry/overview/) and [Mixer Config](/docs/concepts/policies-and-telemetry/config/). * Discover the full [Attribute Vocabulary](/docs/reference/config/policy-and-telemetry/attribute-vocabulary/). * Refer to the [In-Depth Telemetry](/docs/guides/telemetry/) guide. * Learn more about [Querying Istio Metrics](/docs/tasks/telemetry/querying-metrics/). * Learn more about the [MongoDB-specific statistics generated by Envoy](https://www.envoyproxy.io/docs/envoy/latest/configuration/network_filters/mongo_proxy_filter#statistics).