Looking for a low friction way to spin up VMs in UTM for setting up homelab environments on an adequately specced MacBook. Sweet sweet (unified) memories.
utmctl provides some options for starting, sotpping and cloning machines
SUBCOMMANDS:
list Enumerate all registered virtual machines.
status Query the status of a virtual machine.
start Start a virtual machine or resume a suspended virtual machine.
suspend Suspend running a virtual machine to memory.
stop Shuts down a running virtual machine.
attach Redirect the serial input/output to this terminal.
file Guest agent file operations.
exec Execute an application on the guest.
ip-address List all IP addresses associated with network interfaces on the guest.
clone Clone an existing virtual machine.
delete Delete a virtual machine (there is no confirmation).
usb USB device handling.
This provides the basics, but some important settings cannot be changed from here. Most notably changing the MAC address of a cloned machine. In typical homelab scenarios for me, I want to use Shared Networking and after cloning a machine, perhaps multiple times, if they all have the same MAC address, the internal (QEMU?) DHCP server will assign the same IP address. I would like to be able to have a limited number of preconfigured VMs on the ready which I can clone using the least amount of effort possible. I should be able to give the VM a name, which should be its hostname, and add a few lines to my ssh config to be able to reach the machine using that name.
Template VM prerequisites
- Up to date base install
- qemu-guest-agent
- sshd running with my public key
- Dynamic IP Configuration (DHCP)
- Additional software:
- Backend services (ceph, incus, postgres, nginx, etc.)
- GUI tools (vscode, sublime text, browser, HTTPS client for API testing, etc.)
A handful of templates will need to be defined with a combination of additional softwares.
How it should work
I would ideally have a script that allows me to:
- Select any of the Template VMs
- Ask for a new hostname
It should result in a cloned VM, with a new name (in UTM and within the VM) new MAC address and IPv4 address and it should allow me to immediately SSH into that host using a predefined config in ~/.ssh/config
e.g.
maarten@MBP ~ % utmclone
Select Template:
1. Ubuntu 22.04 LTS
2. Debian 11 LTS
3. Arch 2024.10.01
> please enter a number [Default: 1]: 2
> please enter a new hostname for Debian 11 LTS: my-new-clone
Cloning Debian 11 LTS... Done.
Randomizing MAC Address... Done.
Starting VM... Done.
Changing hostname... Done.
Found IPv4 Address: 192.168.64.72
Setting SSH config:... Done.
Adding to /etc/hosts... Done.
You can now connect to your new machine "ssh my-new-clone"
maarten@MBP ~ % ssh my-new-clone
maarten@my-new-clone:~$
Most of these things can be done using utmclone except as it stands, changing the MAC address. Luckily someone figured out how to do this using applescript! Although there are some limitations / caveats at first sight.
#!/bin/bash
VM_NAME="my_virtual_machine"
# Create a VM clone
utmctl clone "${VM_NAME}" --name "${VM_NAME}-clone"
# Randomize the MAC address
# (setting an empty string tells UTM to generate a random MAC)
osascript <<END
tell application "UTM"
set vm to virtual machine named "${VM_NAME}-clone"
set config to configuration of vm
set item 1 of network interfaces of config to {address:""}
update configuration of vm with config
end tell
END
Source: ServerFault - The UTM applescript cheatsheet can be found here
Perhaps it’ll turn out to be easiest to do everything using applescript, as it seems it is able to do everything I need. To be continued…