adding observability and otel

Signed-off-by: Andrew Steurer <[email protected]>

content/en/docs/reference/spin-app-executor.md

@@ -136,5 +136,58 @@ will be created containing the certificates. If no secret name is
 defined in `CACertSecret` the secret name will be `spin-ca`.<br/>
         </td>
         <td>false</td>
+      </tr><tr>
+        <td><b>otel</b></td>
+        <td>string</td>
+        <td>
+          Otel creates environment variables which configure where and how telemetry data is exported from the Spin app.
+        </td>
+        <td>false</td>
       </tr></tbody>
 </table>
+
+### `SpinAppExecutor.spec.deploymentConfig.otel`
+
+<small>[back to parent](#spinappexecutorspecdeploymentconfig)</small>
+
+Otel creates environment variables which configure where and how telemetry data is exported from the Spin app.
+
+<table>
+    <thead>
+        <tr>
+            <th>Name</th>
+            <th>Type</th>
+            <th>Description</th>
+            <th>Required</th>
+        </tr>
+    </thead>
+    <tbody><tr>
+      <td><b>exporter_otlp_endpoint</b></td>
+      <td>string</td>
+      <td>
+        Defines an endpoint to where all metrics, log, and trace data are exported.
+      </td>
+      <td>false</td>
+    </tr><tr>
+      <td><b>exporter_otlp_traces_endpoint</b></td>
+      <td>string</td>
+      <td>
+        Defines an endpoint to where all trace data are exported.
+      </td>
+      <td>false</td>
+    </tr><tr>
+      <td><b>exporter_otlp_metrics_endpoint</b></td>
+      <td>string</td>
+      <td>
+        Defines an endpoint to where all metrics data are exported.
+      </td>
+      <td>false</td>
+    </tr><tr>
+      <td><b>exporter_otlp_logs_endpoint</b></td>
+      <td>string</td>
+      <td>
+        Defines an endpoint to where all log data are exported.
+      </td>
+      <td>false</td>
+    </tr>
+

content/en/docs/topics/observing-spinkube.md

@@ -0,0 +1,153 @@
+---
+title: Observing SpinKube
+description: How to view telemetry data from your Spin apps running in SpinKube.
+weight: 13
+---
+
+This topic guide shows you how to configure SpinKube so your Spin apps export telemetry data to OpenTelemetry collector and Jaeger.
+
+## Prerequisites
+
+Please ensure you have the following tools installed before continuing:
+
+- [kubectl](https://kubernetes.io/docs/tasks/tools/) - the Kubernetes CLI
+- [Helm](https://helm.sh) - the package manager for Kubernetes
+- [SpinKube](https://www.spinkube.dev/docs/spin-plugin-kube/installation) - the Kubernetes plugin for Spin
+
+## About OpenTelemetry Collector
+
+From the OpenTelemetry [documentation](https://opentelemetry.io/docs/collector/):
+>> The OpenTelemetry Collector offers a vendor-agnostic implementation of how to receive, process and export telemetry data. It removes the need to run, operate, and maintain multiple agents/collectors. This works with improved scalability and supports open source observability data formats (e.g. Jaeger, Prometheus, Fluent Bit, etc.) sending to one or more open source or commercial backends.
+
+In our case, the OpenTelemetry collector serves as a single endpoint to receive and route telemetry data, letting us to monitor metrics, traces, and logs via our preferred UIs.
+
+## About Jaeger
+
+From the Jaeger [documentation](https://www.jaegertracing.io/docs/):
+>> Jaeger is a distributed tracing platform released as open source by Uber Technologies. With Jaeger you can: Monitor and troubleshoot distributed workflows, Identify performance bottlenecks, Track down root causes, Analyze service dependencies
+
+Here, we have the OpenTelemetry collector send the trace data to Jaeger.
+
+## Deploy OpenTelemetry Collector
+
+First, add the OpenTelemetry collector Helm repository:
+
+```sh
+helm repo add open-telemetry https://open-telemetry.github.io/opentelemetry-helm-charts
+helm repo update
+```
+
+Next, deploy the OpenTelemetry collector to your cluster:
+
+```sh
+helm upgrade --install otel-collector open-telemetry/opentelemetry-collector \
+    --set image.repository="otel/opentelemetry-collector-k8s" \
+    --set nameOverride=otel-collector \
+    --set mode=deployment \
+    --set config.exporters.otlp.endpoint=http://jaeger-collector.default.svc.cluster.local:4317 \
+    --set config.exporters.otlp.tls.insecure=true \
+    --set config.service.pipelines.traces.exporters[0]=otlp \
+    --set config.service.pipelines.traces.processors[0]=batch \
+    --set config.service.pipelines.traces.receivers[0]=otlp \
+    --set config.service.pipelines.traces.receivers[1]=jaeger
+```
+
+## Deploy Jaeger
+
+Next, add the Jaeger Helm repository:
+
+```sh
+helm repo add jaegertracing https://jaegertracing.github.io/helm-charts
+helm repo update
+```
+
+Then, deploy Jaeger to your cluster:
+
+```sh
+helm upgrade --install jaeger jaegertracing/jaeger \
+    --set provisionDataStore.cassandra=false \
+    --set allInOne.enabled=true \
+    --set agent.enabled=false \
+    --set collector.enabled=false \
+    --set query.enabled=false \
+    --set storage.type=memory
+```
+
+## Configure the SpinAppExecutor
+
+The `SpinAppExecutor` resource determines how Spin applications are deployed in the cluster. The following configuration will ensure that any `SpinApp` resource using this executor will send telemetry data to the OpenTelemetry collector. To see a comprehensive list of OTel options for the `SpinAppExecutor`, see the [API reference](https://www.spinkube.dev/docs/reference/spin-app-executor/).
+
+Create a file called `executor.yaml` with the following content:
+
+```yaml
+apiVersion: core.spinoperator.dev/v1alpha1
+kind: SpinAppExecutor
+metadata:
+  name: otel-shim-executor
+spec:
+  createDeployment: true
+  deploymentConfig:
+    runtimeClassName: wasmtime-spin-v2
+    installDefaultCACerts: true
+    otel:
+      exporter_otlp_endpoint: http://otel-collector.default.svc.cluster.local:4318
+```
+
+To deploy the executor, run:
+
+```sh
+kubectl apply -f executor.yaml
+```
+
+## Deploy a Spin app to observe
+
+With everything in place, we can now deploy a `SpinApp` resource that uses the executor `otel-shim-executor`.
+
+Create a file called `app.yaml` with the following content:
+
+```yaml
+apiVersion: core.spinoperator.dev/v1alpha1
+kind: SpinApp
+metadata:
+  name: otel-spinapp
+spec:
+  image: ghcr.io/spinkube/spin-operator/cpu-load-gen:20240311-163328-g1121986
+  executor: otel-shim-executor
+  replicas: 1
+```
+
+Deploy the app by running:
+
+```sh
+kubectl apply -f app.yaml
+```
+
+Congratulations! You now have a Spin app exporting telemetry data.
+
+Next, we need to generate telemetry data for the Spin app to export. Use the below command to port-forward the Spin app:
+
+```sh
+kubectl port-forward svc/otel-spinapp 3000:80
+```
+
+In a new terminal window, execute a `curl` request:
+
+```sh
+curl localhost:3000
+```
+
+The request will take a couple of moments to run, but once it's done, you should see an output similar to this:
+
+```
+fib(43) = 433494437
+```
+
+## Interact with Jaeger
+
+To view the traces in Jaeger, use the following port-forward command:
+
+```sh
+kubectl port-forward svc/jaeger-query 16686:16686
+```
+
+Then, open your browser and navigate to `localhost:16686` to interact with Jaeger's UI.