docs: adding an instruction to enable ip_tables

In a Linux system host, if you're enabling the Contour ingress controller
while creating the kind cluster, and the ip_tables module is not enabled
in the host system, the envoy pod will fail to be deployed with the
following error message:

Failed to create pod sandbox: rpc error: code = Unknown desc =
failed to setup network for sandbox "xyz": plugin type="portmap"
failed (add): unable to create chain CNI-HOSTPORT-SETMARK:
failed to check iptables chain existence:
running [/usr/sbin/iptables -t nat -S CNI-HOSTPORT-SETMARK 1 --wait]:
exit status 3: modprobe: ERROR: could not insert 'ip_tables':
Operation not permitted...

Signed-off-by: Alexon Oliveira <[email protected]>

Author: AlexonOliveiraRH

Diff for: website/docs/kind/installing-extension.md

@@ -27,3 +27,9 @@ The Kind extension provides the capability of creating a local Kubernetes cluste
 The following video provides a complete guide on creating a single-node cluster:
 
 <ReactPlayer playing playsinline controls url='https://github.com/containers/podman-desktop-media/raw/refs/heads/kind/video/cluster-creation-kind.mp4' width='100%' height='100%' />
+
+:::note
+
+If you are running Podman Desktop in a Linux system host and enabling the Contour ingress controller, you need to ensure that the `ip_tables` module is loaded, otherwise the `envoy` pod will fail to insert an iptable rule that it needs in order to be deployed (`/usr/sbin/iptables -t nat -S CNI-HOSTPORT-SETMARK 1 --wait`). To accomplish that, run the command `sudo modprobe ip_tables` to enable the required module, and then the command `lsmod | grep ip_tables` to check if it is enabled.
+
+:::