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Merge pull request #13666 from adellape/osdk_metrics
Add monitoring to OSDK
2 parents 5d5f0bb + 784ff29 commit 2d5a49b

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‎_topic_map.yml‎

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@@ -119,6 +119,8 @@ Topics:
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File: osdk-ansible
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- Name: Creating Helm-based Operators
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File: osdk-helm
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- Name: Configuring built-in monitoring with Prometheus
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File: osdk-monitoring-prometheus
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- Name: Operator SDK CLI reference
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File: osdk-cli-reference
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- Name: Migrating to Operator SDK v0.1.0

‎applications/operator_sdk/osdk-getting-started.adoc‎

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:relfileprefix: ../
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[id='getting-started-osdk']
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[id='osdk-getting-started']
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= Getting started with the Operator SDK
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include::modules/common-attributes.adoc[]
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:context: osdk-getting-started
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(the `operator-sdk` CLI tool and `controller-runtime` library API) and the
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Operator Lifecycle Manager (OLM).
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include::modules/osdk-operator-sdk.adoc[leveloffset=+1]
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include::modules/osdk-architecture.adoc[leveloffset=+1]
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include::modules/osdk-monitoring-prometheus-operator-support.adoc[leveloffset=+2]
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include::modules/osdk-installing-cli.adoc[leveloffset=+1]
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include::modules/building-memcached-operator-using-osdk.adoc[leveloffset=+1]
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include::modules/managing-memcached-operator-using-olm.adoc[leveloffset=+1]

‎applications/operator_sdk/osdk-migrating-to-v0-1-0.adoc‎

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. Modify the new project as described for v0.1.0.
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This guide uses the `memcached-operator`, the example project
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from xref:osdk-getting-started.adoc#getting-started-osdk[Getting started with the Operator SDK],
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from xref:osdk-getting-started.adoc#osdk-getting-started[Getting started with the Operator SDK],
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to illustrate the migration steps. See the
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link:https://github.com/operator-framework/operator-sdk-samples/tree/aa15bd278eec0959595e0a0a7282a26055d7f9d6/memcached-operator[v0.0.7 memcached-operator]
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and

‎applications/operator_sdk/osdk-monitoring-prometheus.adoc‎

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:relfileprefix: ../
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[id='osdk-monitoring-prometheus']
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= Configuring built-in monitoring with Prometheus
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include::modules/common-attributes.adoc[]
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:context: osdk-monitoring-prometheus
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toc::[]
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include::modules/osdk-monitoring-prometheus-operator-support.adoc[leveloffset=+1]
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include::modules/osdk-monitoring-prometheus-metrics-helper.adoc[leveloffset=+1]
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include::modules/osdk-monitoring-prometheus-metrics-helper-modifying-port.adoc[leveloffset=+2]
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include::modules/osdk-monitoring-prometheus-servicemonitor.adoc[leveloffset=+1]
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include::modules/osdk-monitoring-prometheus-servicemonitor-creating.adoc[leveloffset=+2]

‎modules/osdk-operator-sdk.adoc‎ renamed to ‎modules/osdk-architecture.adoc‎

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//
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// * applications/operator_sdk/osdk-getting-started.adoc
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[id='osdk-operator-sdk-{context}']
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[id='osdk-architecture-{context}']
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= Architecture of the Operator SDK
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The link:https://coreos.com/operators/[Operator Framework] is an open source
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- Tools for scaffolding and code generation to quickly bootstrap a new project
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- Extensions to cover common Operator use cases
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[discrete]
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=== Operator SDK workflow
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[id='osdk-architecture-workflow-{context}']
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== Workflow
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The SDK provides the following workflow to develop a new Operator:
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resources in a user-defined handler and takes actions to reconcile the state of
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the application.
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[discrete]
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=== Manager
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[id='osdk-architecture-manager-{context}']
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== Manager file
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The main program for the Operator is the manager `cmd/manager/main.go` file. The
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manager automatically registers the scheme for all Custom Resources (CRs) defined
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under `pkg/apis/` and runs all controllers under `pkg/controller/`.
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The main program for the Operator is the manager file at `cmd/manager/main.go`.
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The manager automatically registers the scheme for all Custom Resources (CRs)
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defined under `pkg/apis/` and runs all controllers under `pkg/controller/`.
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The manager can restrict the namespace that all controllers watch for resources:
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‎modules/osdk-monitoring-prometheus-metrics-helper-modifying-port.adoc‎

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// Module included in the following assemblies:
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//
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// * applications/operator_sdk/osdk-monitoring-prometheus.adoc
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[id='osdk-monitoring-prometheus-metrics-helper-modifying-port-{context}']
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= Modifying metrics port
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Operator authors can modify the port that metrics are exposed on.
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.Prerequisites
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- Go-based Operator generated using the Operator SDK
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- Kubernetes-based cluster with the Prometheus Operator deployed
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.Procedure
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. In the generated Operator's `cmd/manager/main.go` file, change the `var
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metricsPort int32 = 8383` variable.

‎modules/osdk-monitoring-prometheus-metrics-helper.adoc‎

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// Module included in the following assemblies:
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//
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// * applications/operator_sdk/osdk-monitoring-prometheus.adoc
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[id='osdk-monitoring-prometheus-metrics-helper-{context}']
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= Metrics helper
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In Go-based Operators generated using the Operator SDK, the following helper
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function exposes general metrics about the running program:
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[source,go]
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----
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func ExposeMetricsPort(ctx context.Context, port int32) (*v1.Service, error)
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----
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These metrics are inherited from the `controller-runtime` library API. The
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metrics are by default served on `:8383/metrics`.
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A Service object is created with the metrics port exposed, which can be then
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accessed by Prometheus. The Service object is garbage collected when the leader
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Pod's root owner is deleted.
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The following example is present in the `cmd/manager/main.go` file in all
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Operators generated using the Operator SDK:
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[source,go]
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----
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import(
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"github.com/operator-framework/operator-sdk/pkg/metrics"
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"sigs.k8s.io/controller-runtime/pkg/manager"
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)
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// Change the below variables to serve metrics on different host or port.
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var metricsHost = "0.0.0.0" <1>
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var metricsPort int32 = 8383 <2>
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// Pass metrics address to controller-runtime manager
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mgr, err := manager.New(cfg, manager.Options{
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Namespace: namespace,
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MetricsBindAddress: fmt.Sprintf("%s:%d", metricsHost, metricsPort),
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})
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...
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// Create Service object to expose the metrics port.
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_, err = metrics.ExposeMetricsPort(ctx, metricsPort)
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if err != nil {
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// handle error
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log.Info(err.Error())
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}
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----
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<1> Host the metrics are exposed on.
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<2> Port the metrics are exposed on.

‎modules/osdk-monitoring-prometheus-operator-support.adoc‎

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// Module included in the following assemblies:
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//
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// * applications/operator_sdk/osdk-getting-started.adoc
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// * applications/operator_sdk/osdk-monitoring-prometheus.adoc
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[id='osdk-monitoring-prometheus-operator-support-{context}']
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= Prometheus Operator support in the Operator SDK
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link:https://prometheus.io/[Prometheus] is an open-source systems monitoring and
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alerting toolkit. The Prometheus Operator creates, configures, and manages
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Prometheus clusters running on Kubernetes-based clusters, such as
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{product-title}.
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Helper functions exist in the Operator SDK by default to automatically set up
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metrics in any generated Go-based Operator for use on clusters where the
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Prometheus Operator is deployed.

‎modules/osdk-monitoring-prometheus-servicemonitor-creating.adoc‎

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// Module included in the following assemblies:
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//
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// * applications/operator_sdk/osdk-monitoring-prometheus.adoc
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[id='osdk-monitoring-prometheus-servicemonitor-creating-{context}']
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= Creating ServiceMonitor resources
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Operator authors can add Service target discovery of created monitoring Services
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using the `metrics.CreateServiceMonitor()` helper function, which accepts the
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newly created Service.
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.Prerequisites
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- Go-based Operator generated using the Operator SDK
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- Kubernetes-based cluster with the Prometheus Operator deployed
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.Procedure
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. Add the `metrics.CreateServiceMonitor()` helper function to your Operator code,
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creating only one `ServiceMonitor` per application and namespace:
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[source,go]
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----
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import "github.com/operator-framework/operator-sdk/pkg/metrics"
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serviceMonitors, err := metrics.CreateServiceMonitors(config *rest.Config, ns string, services []*v1.Service) <1>
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if err != nil {
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<2>
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}
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----
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<1> Pass the Service(s) to the helper function, which in turn returns the ServiceMonitor object.
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<2> Handle errors here.

‎modules/osdk-monitoring-prometheus-servicemonitor.adoc‎

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// Module included in the following assemblies:
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//
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// * applications/operator_sdk/osdk-monitoring-prometheus.adoc
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[id='osdk-monitoring-prometheus-servicemonitor-{context}']
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= ServiceMonitor resources
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A ServiceMonitor is a Custom Resource Definition (CRD) provided by the
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Prometheus Operator that discovers the `Endpoints` in Service objects and
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configures Prometheus to monitor those Pods.
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In Go-based Operators generated using the Operator SDK, the
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`GenerateServiceMonitor()` helper function can take a Service object and
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generate a ServiceMonitor Custom Resource (CR) based on it.
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.Additional resources
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- See the
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link:https://github.com/coreos/prometheus-operator/blob/7a25bf6b6bb2347dacb235659b73bc210117acc7/Documentation/design.md#servicemonitor[Prometheus Operator documentation]
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for more about the ServiceMonitor CRD.

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