docs: Add new file for Pprof tutorial.

docs/book/src/cronjob-tutorial/pprof-tutorial.md

@@ -0,0 +1,68 @@
+# Monitoring Performance with Pprof
+
+`pprof` is a Go profiling tool integrated within the `controller-runtime` library, designed to help identify performance bottlenecks in areas such as CPU usage, memory allocation, and more. This profiling tool, from the Go package [`net/http/pprof`][pprof-go-docs], is especially useful for diagnosing performance issues by providing detailed insights into resource usage during the runtime of your application.
+
+`pprof` is integrated into the HTTP server used by the `controller-runtime` manager, allowing you to collect profiling data via HTTP endpoints. This data can then be visualized using `go tool pprof`. Pprof feature is built into the `controller-runtime` library, so there is no need to install it separately.
+
+The `controller-runtime` [Manager options][manager-options-doc] provide an easy way to enable `pprof`, allowing you to gather detailed runtime metrics for improving the performance of your controllers.
+
+For further information about the Pprof, check out the official [Github repository][github-repo].
+
+<aside class="warning">
+<h1>Pprof Not Recommended for Production</h1>
+
+While [Pprof][github-repo] is an excellent tool for profiling and debugging, it is not recommended to leave it enabled in production environments. The primary reasons are:
+
+1. **Security Risk**: The profiling endpoints expose detailed information about your application's performance and resource usage, which could be exploited if accessed by unauthorized users.
+2. **Overhead**: Continuous profiling can introduce performance overhead, especially under heavy load, potentially impacting production workloads.
+
+</aside>
+
+## How to use Pprof in your Codebase
+
+1. In your `cmd/main.go` file, add the following `controller-runtime` manager field to enable the `pprof` endpoints:
+
+    ```golang
+    mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
+      ...
+      // PprofBindAddress is the TCP address that the controller should bind to
+      // for serving pprof. Specify the manager address and the port that should be bind.
+      PprofBindAddress:       ":8082",
+      ...
+    })
+    ```
+
+2. Start your controller on your localhost:
+
+    ```bash
+    make run
+    ```
+
+3. Deploy your custom resource on Kind, or any other Kubernetes cluster. Wait for the pods to be ready.
+
+    ```bash
+    kubectl apply -f config/samples/batch_v1_cronjob.yaml
+    ```
+
+4. Use `curl` to export the profiling statistics into a file. Note that the **URL hit should be same as the one specified in the `PprofBindAddress` field of your Controller's Manager**.
+
+    ```bash
+    curl -s "http://127.0.0.1:8082/debug/pprof/profile" > ./cpu-profile.out
+    ```
+
+5. Visualize the results on an interactive dashboard.
+
+    ```bash
+    # Go tool will open a session on port 8080.
+    # You can change this as per your own need.
+    go tool pprof -http=:8080 ./cpu-profile.out
+    ```
+
+    Visualizaion resutls will vary depending on the deployed workload, and the Controller's behavior.
+    However, you'll see a dashboard on your browser similar to this one:
+
+    ![pprof-result-visualization](./images/pprof-result-visualization.png)
+
+[pprof-go-docs]: https://pkg.go.dev/net/http/pprof
+[manager-options-doc]: https://pkg.go.dev/sigs.k8s.io/controller-runtime/pkg/manager
+[github-repo]: https://github.com/google/pprof

docs/book/src/reference/reference.md

@@ -27,6 +27,8 @@
       - [Object/DeepCopy](markers/object.md)
       - [RBAC](markers/rbac.md)
 
+  - [Performance Profiling with Pprof](../cronjob-tutorial/pprof-tutorial.md)
+
   - [controller-gen CLI](controller-gen.md)
   - [completion](completion.md)
   - [Artifacts](artifacts.md)