📖 add kustomize v1 docs

Author: camilamacedo86

docs/book/src/plugins/available-plugins.md

@@ -2,4 +2,5 @@
 
 This section details how to use the currently available plugins in Kubebuilder. 
 
-  - [Declarative V1](declarative-v1.md)
+  - [Declarative V1](declarative-v1.md)
+  - [Kustomize V1](kustomize-v1.md)

docs/book/src/plugins/kustomize-v1.md

@@ -0,0 +1,98 @@
+# Kustomize Plugin
+
+The kustomize plugin allows you to scaffold all kustomize manifests used to work with the language plugins such as `go/v2` and `go/v3`. 
+By using the kustomize plugin, you can create your own language plugins and ensure that you will have the same configurations 
+and features provided by it. 
+
+Note that projects such as [Operator-sdk][sdk] consume the Kubebuilder project as a lib and provide options to work with other languages
+like Ansible and Helm. The kustomize plugin allows them to easily keep a maintained configuration and ensure that all languages have
+the same configuration. It is also helpful if you are looking to provide nice plugins which will perform changes on top of
+what is scaffolded by default. With this approach we do not need to keep manually updating this configuration in all possible language plugins
+which uses the same and we are also
+able to create "helper" plugins which can work with many projects and languages.
+
+<aside class="note">
+<h1>Examples</h1>
+
+You can check the kustomize content by looking at the `config/` directory. Samples are provided under the [testdata][testdata]
+directory of the Kubebuilder project.
+
+</aside> 
+
+
+## When to use it
+
+- If you are looking to scaffold the kustomize configuration manifests for your own language plugin 
+
+## How to use it
+
+If you are looking to define that your language plugin should use kustomize use the [Bundle Plugin][bundle]
+to specify that your language plugin is a composition with your plugin responsable for scaffold
+all that is laguage specific and kustomize for its configuration, see: 
+
+```go
+	// Bundle plugin which built the golang projects scaffold by Kubebuilder go/v3
+	// The follow code is creating a new plugin with its name and version via composition
+	// You can define that one plugin is composite by 1 or Many others plugins
+	gov3Bundle, _ := plugin.NewBundle(golang.DefaultNameQualifier, plugin.Version{Number: 3},
+		kustomizecommonv1.Plugin{}, // scaffold the config/ directory and all kustomize files
+		golangv3.Plugin{}, // Scaffold the Golang files and all that specific for the language e.g. go.mod, apis, controllers
+	)
+```
+
+Also, with Kubebuilder, you can use kustomize alone via:
+
+```sh
+kubebuilder init --plugins=kustomize/v1 
+$ ls -la 
+total 24
+drwxr-xr-x   6 camilamacedo86  staff  192 31 Mar 09:56 .
+drwxr-xr-x  11 camilamacedo86  staff  352 29 Mar 21:23 ..
+-rw-------   1 camilamacedo86  staff  129 26 Mar 12:01 .dockerignore
+-rw-------   1 camilamacedo86  staff  367 26 Mar 12:01 .gitignore
+-rw-------   1 camilamacedo86  staff   94 31 Mar 09:56 PROJECT
+drwx------   6 camilamacedo86  staff  192 31 Mar 09:56 config
+```
+
+Or combined with the base language plugins:
+
+```sh
+# Provides the same scaffold of go/v3 plugin which is a composition (kubebuilder init --plugins=go/v3)
+kubebuilder init --plugins=kustomize/v1,base.go.kubebuilder.io/v3 --domain example.org --repo example.org/guestbook-operator 
+```
+
+## Subcommands
+
+The kustomize plugin implements the following subcommands:
+
+* init (`$ kubebuilder init [OPTIONS]`)
+* create api (`$ kubebuilder create api [OPTIONS]`)
+* create webhook (`$ kubebuilder create api [OPTIONS]`)
+
+<aside class="note">
+<h1>Create API and Webhook</h1>
+
+Its implementation for the subcommand create api will scaffold the kustomize manifests
+which are specific for each API, see [here][kustomize-create-api]. The same applies
+to its implementation for create webhook.
+
+</aside> 
+
+## Affected files
+
+The following scaffolds will be created or updated by this plugin:
+
+* `config/*`
+
+## Further resources
+
+* Check the kustomize [plugin implementation](https://github.com/kubernetes-sigs/kubebuilder/tree/master/pkg/plugins/common/kustomize) 
+* Check the [kustomize documentation][kustomize-docs]
+* Check the [kustomize repository][kustomize-github]
+
+[sdk]:https://github.com/operator-framework/operator-sdk
+[testdata]: https://github.com/kubernetes-sigs/kubebuilder/tree/master/testdata/
+[bundle]: https://github.com/kubernetes-sigs/kubebuilder/blob/master/pkg/plugin/bundle.go
+[kustomize-create-api]: https://github.com/kubernetes-sigs/kubebuilder/blob/master/pkg/plugins/common/kustomize/v1/scaffolds/api.go#L72-L84
+[kustomize-docs]: https://kustomize.io/
+[kustomize-github]: https://github.com/kubernetes-sigs/kustomize