homelab-server-v2/docs/01_hypervisor_networking.md

Hypervisor & Bridge Networking

This section describes the host operating system installation, the physical network bridge configuration, KVM storage layout, and the static DHCP reservation design for Homelab Version 2.

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Physical Host System Baseline

• Hardware Platform: Headless BOSGAME P3 Lite Mini PC (AMD Ryzen 7 6800H / 32GB DDR5 RAM / 1TB NVMe SSD).
• Operating System: AlmaLinux 10 (Red Hat Enterprise Linux 10 downstream compatible).
• Storage Configuration: Logical Volume Manager (LVM) partition layout configured during OS install:
  • / (Root): 100GB XFS filesystem for the base OS.
  • /var/lib/libvirt/images/vm_pool: Remaining disk space (~850GB) dedicated to guest virtual machine volumes, backed by an optimized LVM thin pool.

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Bridged Network Topology (br0)

To allow virtual machines to act as first-class citizens on the physical network (receiving IP addresses from the home router, responding to ping requests, and broadcasting locally), I binded the host's physical Ethernet card to a software bridge (br0).

graph TD
    subgraph Host ["BOSGAME Physical Host (172.30.1.200)"]
        subgraph Guests ["Virtual Machines (Guests)"]
            VM1["freeipa (172.30.1.85)"]
            VM2["portfolio (172.30.1.94)"]
            VM_Others["Other Guest VMs..."]
        end
        Bridge["Logical Bridge: br0 (172.30.1.200)"]
        NIC["Physical NIC: eno3 (No IP)"]

        Guests -->|vnet interfaces| Bridge
        Bridge --> NIC
    end

    NIC-->|Physical Cable| Router["ISP Router / Local LAN (Gateway: 172.30.1.254)"]

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Physical/Host Bridge Setup (nmcli)

While hypervisor services are automated via Ansible, the initial physical interface bridge is configured on the host command-line to ensure persistent ssh connectivity:

Create the Bridge Interface

sudo nmcli con add type bridge con-name br0 ifname br0

Configure Static IP Parameters

The command is broken down for readability:

sudo nmcli con mod br0 ipv4.addresses "172.30.1.200/24"
sudo nmcli con mod br0 ipv4.gateway "172.30.1.254"
sudo nmcli con mod br0 ipv4.dns "172.30.1.85, 1.1.1.1"
sudo nmcli con mod br0 ipv4.method "manual"
sudo nmcli con mod br0 bridge.stp no

Bind the Physical NIC(e.g. eno3) to the Bridge

sudo nmcli con add type bridge-slave con-name br0-slave ifname eno3 master br0
sudo nmcli con up br0
sudo nmcli con delete eno3

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Automated KVM & Hypervisor Installation

I used Ansible to automate package provisioning, user permission assignments, and system service lifecycle control.

Host Utility Preparation(01_host_prep.yml)

Configures time zone synchronization and installs standard diagnostic/filesystem utilities:

• Enables the EPEL package repository
• Installs dependencies: htop, tmux, git, curl, rsync, and fuse3(critical for subsequent storage mounts).
• Enforces host timezone tracking using timedatectl.

Virtualization & Cockpit Orchestration (02_kvm_setup.yml)

Deploys hypervisor capability and enables GUI system dashboard tools:

• Installs the hypervisor stack: qemu-kvm, libvirt, virt-install.
• Installs Cockpit and cockpit-machines to expose VM lifecycle metrics through the Cockpit Web Console.
• Ensures VM administration permissions by adding the administrative user to the libvirt group.
• Enables and starts systemd services: libvirtd and cockpit.socket.

MAC Address Reservation Table

To guarantee each VM gets a Consistent IP address from the physical router's DHCP server, MAC addresses are hardocded in the Terraform domain definitions and mapped to DHCP reservations inside the local router interface:

VM Name	Operating System	MAC Address	Static IP Address	Primary Role
freeipa	AlmaLinux 10	52:54:00:ee:ef:61	172.30.1.85	Directory Services / BIND DNS
portfolio	Debian 12	52:54:00:ee:ef:62	172.30.1.93	Web Server (NGINX/Portal/Hamster)
minecraft	Debian 12	52:54:00:ee:ef:63	172.30.1.91	Dedicated Game Server
palworld	Ubuntu 24.04	52:54:00:ee:ef:64	172.30.1.90	Dedicated Game Server
navidrome	Debian 12	52:54:00:ee:ef:65	172.30.1.92	Music Streamer + Rclone Mount