Create e VirtML Administrative VM

This guide will take you step-by-step through the process of creating a new virtual machine (VM) using libvirt and installing Debian on it. We’ll use this VM as the administrative machine for the project. After setting it up, we will connect to this machine and use it to run the remaining guides.

What you’ll need

To complete this guide, you will need the following:

A Debian-based system with root access.
A working QEMU/KVM installation.
A Debian 12.x ISO image. You can download it from the Debian website.

Important

The guide assumes that you have already downloaded a Debian 12.x ISO image in the default directory /var/lib/libvirt/images. We will be working with a Debian netinst ISO image, which is a minimal installation image that downloads packages from the internet during the installation process.

Procedure

Follow the steps below to create a new VM and install Debian on it.

Change to the project’s root directory:
```
user:~$ cd /home/user/virtlml
```
Note

Replace /home/user/virtlml with the path to the project’s root directory.

Decide on login credentials for the root user:

user:~/virtml$ export ROOTPW_HASH=$(openssl passwd -6)

Export your public SSH key:

user:~/virtml$ export SSH_KEY=$(cat ~/.ssh/id_rsa.pub)

Export the environment variables for your network settings. Replace the example values with values specific to your network:
- GUEST_IP: The IP address you want to assign to the VM.
- GATEWAY: The network gateway.
- NETMASK: The network mask.
- NAMESERVERS: The network DNS server.
- DOMAIN: The network domain.
```
user:~/virtml$ export GUEST_IP="192.168.20.100"
```
```
user:~/virtml$ export GATEWAY="192.168.20.1"
```
```
user:~/virtml$ export NETMASK="255.255.255.0"
```
```
user:~/virtml$ export NAMESERVERS="192.168.20.1"
```
```
user:~/virtml$ export DOMAIN="example.com"
```

Render the preseed file:

user:~/virtml$ j2 infra/preseed.cfg.j2 > infra/preseed.cfg

Create the new VM using virt-install. The following command will start a new, completely automated, Debian installation. The VM will be on the same network as your host machine, using the br0 bridge.

user:~/virtlml$ virt-install \
    --name virtml-admin \
    --vcpus 1 \
    --cpu mode=host-passthrough \
    --ram 2048 \
    --disk size=24,format=qcow2,cache=none,discard=unmap \
    --location /var/lib/libvirt/images/debian-12.5.0-amd64-netinst.iso \
    --os-variant linux2022 \
    --initrd-inject=infra/preseed.cfg \
    --bridge=br0 \
    --graphics none \
    --extra-args 'auto=true console=ttyS0,115200n8' \
    --boot uefi

Verify

Verify that the VM is running:

user:~/virtlml$ virsh list --all
Id   Name         State
-----------------------------
1    virtml-admin running

Verify that you can SSH into the PXE server VM:

user:~/virtlml$ ssh root@virtml-admin
Linux virtml-admin 6.1.0-20-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.85-1 (2024-04-11) x86_64

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Thu May  2 13:04:36 2024 from 192.168.20.25
root@virtml-admin:~#

Note

Replace virtml-admin with the IP address of the VM. Alternatively, you can set the hostname for the VM in your /etc/hosts file.