Collecting Metrics for TCP services with Mixer
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 sample application is used as the example application throughout this task.
Before you begin
Install Istio with Mixer enabled in your cluster and deploy an application.
The custom configuration needed to use Mixer for telemetry is:
values: prometheus: enabled: true telemetry: v1: enabled: true v2: enabled: false components: citadel: enabled: true telemetry: enabled: true
Please see the guide on Customizing the configuration for information on how to apply these settings.
Once the configuration has been applied, confirm a telemetry-focused instance of Mixer is running:
$ kubectl -n istio-system get service istio-telemetry NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE istio-telemetry ClusterIP 10.4.31.226 <none> 9091/TCP,15004/TCP,15014/TCP,42422/TCP 80s
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
Apply a YAML file with configuration for the new metrics that Istio will generate and collect automatically.
$ kubectl apply -f @samples/bookinfo/telemetry/tcp-metrics.yaml@
Setup Bookinfo to use MongoDB.
Install
v2
of theratings
service.If you are using a cluster with automatic sidecar injection enabled, simply deploy the services using
kubectl
:$ kubectl apply -f @samples/bookinfo/platform/kube/bookinfo-ratings-v2.yaml@
If you are using manual sidecar injection, use the following command instead:
$ kubectl apply -f <(istioctl kube-inject -f @samples/bookinfo/platform/kube/bookinfo-ratings-v2.yaml@) deployment "ratings-v2" configured
Install the
mongodb
service:If you are using a cluster with automatic sidecar injection enabled, simply deploy the services using
kubectl
:$ kubectl apply -f @samples/bookinfo/platform/kube/bookinfo-db.yaml@
If you are using manual sidecar injection, use the following command instead:
$ kubectl apply -f <(istioctl kube-inject -f @samples/bookinfo/platform/kube/bookinfo-db.yaml@) service "mongodb" configured deployment "mongodb-v1" configured
The Bookinfo sample deploys multiple versions of each microservice, so you will start by creating destination rules that define the service subsets corresponding to each version, and the load balancing policy for each subset.
$ kubectl apply -f @samples/bookinfo/networking/destination-rule-all.yaml@
If you enabled mutual TLS, please run the following instead
$ kubectl apply -f @samples/bookinfo/networking/destination-rule-all-mtls.yaml@
You can display the destination rules with the following command:
$ kubectl get destinationrules -o yaml
Since the subset references in virtual services rely on the destination rules, wait a few seconds for destination rules to propagate before adding virtual services that refer to these subsets.
Create
ratings
andreviews
virtual services:$ kubectl apply -f @samples/bookinfo/networking/virtual-service-ratings-db.yaml@ Created config virtual-service/default/reviews at revision 3003 Created config virtual-service/default/ratings at revision 3004
Send traffic to the sample application.
For the Bookinfo sample, visit
http://$GATEWAY_URL/productpage
in your web browser or issue the following command:$ curl http://$GATEWAY_URL/productpage
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:
$ 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 in the Prometheus browser window. Select Graph. Enter the
istio_mongo_received_bytes
metric and select Execute. The table displayed in the Console tab includes entries similar to:istio_mongo_received_bytes{destination_version="v1",instance="172.17.0.18:42422",job="istio-mesh",source_service="ratings-v2",source_version="v2"}
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 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.
Cleanup
Remove the new telemetry configuration:
$ kubectl delete -f @samples/bookinfo/telemetry/tcp-metrics.yaml@
If you are using Istio 1.1.2 or prior:
$ kubectl delete -f @samples/bookinfo/telemetry/tcp-metrics-crd.yaml@
Remove the
port-forward
process:$ killall kubectl
If you are not planning to explore any follow-on tasks, refer to the Bookinfo cleanup instructions to shutdown the application.