Lab Architecture

Overview¶

This document describes the network configuration and virtual machine layout for a KVM-based home lab using libvirt on a Linux host. It is intended as a reference for anyone wanting to replicate a similar setup.

Host Network Interfaces Overview¶

The host machine (jarvis) has the following network interfaces:

Interface Details¶

enp8s0: Physical NIC connected to your LAN.
virbr1: Custom bridge for VMs to connect to each other with subnet 192.168.10.0/24.
vnet0–vnet3: Virtual interfaces created automatically by libvirt when VMs start; attached to virbr1.

Virtual Machines¶

The home lab includes 4 running VMs:

ID	Name	State	Role	Network Interface
2	bastion01	running	Internal DNS + Tailscale Exit Node	vnet0
3	master01	running	Kubernetes Control Plane	vnet1
4	worker01	running	Kubernetes Worker Node	vnet2
5	worker02	running	Kubernetes Worker Node	vnet3

Each VM is attached to the virbr1 bridge network and can communicate with each other and the host.

Networking Mode: NAT¶

The virbr1 interface operates in NAT (Network Address Translation) mode. This means:

VMs are on a private subnet managed by libvirt (e.g., 192.168.10.0/24).
VMs can access the internet via the host’s connection.
VMs can talk to each other and the host.
LAN devices cannot initiate connections to the VMs by default. Port forwarding will be used to allow external access from Internet.

Bastion: Internal DNS + Tailscale Agent¶

Currently, the bastion01 VM serves two key roles:

1. Internal DNS Server (BIND9)¶

Provides DNS resolution for VMs using BIND9.
Hosts an authoritative zone for internal services (*.lab.riupie.com).
Forwards unknown queries to external DNS servers (e.g., 1.1.1.1, 8.8.8.8).

2. Tailscale Agent (Subnet Router / Exit Node)¶

Runs a Tailscale client authenticated to Tailnet.
Acts as a subnet router, advertising the internal VM network to my Tailnet.
Allows remote access to all VMs over Tailscale without port forwarding.