docs(k8s): add command line to show resource usage by resource kind

pages/kubernetes/how-to/recover-space-etcd.mdx

@@ -22,6 +22,19 @@ This guide helps you to free up space on your database to avoid reaching this li
 - [Created](/kubernetes/how-to/create-cluster/) a Kubernetes Kapsule cluster
 - [Downloaded](/kubernetes/how-to/connect-cluster-kubectl/) the Kubeconfig
 
+* Dump your cluster resources to YAML format and show the characters count, you will have a rough estimation where to look for space to claim
+
+```sh
+> kubectl api-resources --verbs=list --namespaced -o name | while read type; do echo -n "Kind: ${type}, Size: "; kubectl get $type -o yaml -A | wc -c; done
+Kind: configmaps, Size: 1386841
+Kind: endpoints, Size: 82063
+Kind: events, Size: 375065
+Kind: limitranges, Size: 68
+Kind: persistentvolumeclaims, Size: 68
+Kind: pods, Size: 3326153
+[...]
+```
+
 * Looking for unused resources is a good approach, delete any Secrets, large ConfigMaps that are not used anymore in your cluster.
 
   ```sh
@@ -51,4 +64,4 @@ Look for resources with an external apiversion (not _v1_, _apps/v1_, _storage.k8
   ```sh
   > kubectl get nodefeature -n kube-system   $node-feature-name -o yaml | wc -c
     305545 // ~300KiB, big object
-  ```
+  ```