# Using virt-install to create unattended virtual machine install ## Introduction [Virt-manager](https://en.wikipedia.org/wiki/Virt-manager) is a great tool to replace [VirtualBox](https://en.wikipedia.org/wiki/Virtualbox) or [VMware Workstation](https://en.wikipedia.org/wiki/VMware_Workstation) on Linux, when [GNOME boxes](https://en.wikipedia.org/wiki/GNOME_Boxes) is not enough. I use virtualization on a daily basis and often need to set-up new virtual machines (VM). Virt-manager has a wizard to create new VM, where you specify the ISO, select all you need, but then we have to go through the installation process. All that takes time, so to speed up, instead of going through the GUI, we'll use `virt-install`(install `virt-install` package if needed) to create an unattended installation of a [debian](https://www.debian.org/) server with just a serial console. ## Unattended VM creation We first need to create a password file for `root` and one for the user. They are in plaintext, and the password must be on the first line: ```plaintext echo "toor" > root-pwd.txt echo "resu" > user-pwd.txt ``` Now let's do the installation: ```plaintext virt-install --install debian12 \ --graphics none \ --console pty,target_type=serial \ --noautoconsole \ --extra-args="console=ttyS0,115200n8" \ --unattended profile=jeos,admin-password-file=root-pwd.txt,user-login=user,user-password-file=user-pwd.txt ``` Let's go through the options: * `--install debian12`: Use debian 12. To list all the possible options, use `osinfo-query os`. What we need is the `shortcode`. * `--graphics none`: No graphics (We can add later on) but since this is a server, we'll just use SSH * `--console pty,target_type=serial`: Add a [PTY](https://en.wikipedia.org/wiki/Pseudoterminal) console to the virtual machine * `--noautoconsole`: Don't automatically try to connect to the guest console * `--extra-args="console=ttyS0,115200n8"`: Arguments when starting the kernel to output to the serial console * `--unattended profile=jeos,admin-password-file=root-pwd.txt,user-login=user,user-password-file=user-pwd.txt`: Make an unattended installation. If not specified, we'll have to install ourselves. * `profile=jeos`: Use the [JeOS](https://en.wikipedia.org/wiki/Just_enough_operating_system) profile (instead of default `desktop`) * `admin-password-file=password.txt`: Use the password in the `password.txt` file we created just before for `root`. * `user-login=user,user-password-file=user-pwd.txt`: Create a user named `user`with the password provided in the file. By default [OpenSSH](https://www.openssh.com/) doesn't allow `root` to connect, so if we don't have a user, we won't be able to connect via SSH. It will output something similar to: ```plaintext Using default --name debian12 Using debian12 default --memory 2048 Using debian12 default --disk size=20 Starting install... Retrieving 'linux' | 7.6 MB 00:14 ... Retrieving 'initrd.gz' | 39 MB 01:05 ... Allocating 'virtinst-pm9z6mm7-linux' | 0 B 00:00 ... Transferring 'virtinst-pm9z6mm7-linux' | 0 B 00:00 ... Allocating 'virtinst-c_yhjtv8-initrd.gz' | 0 B 00:00 ... Transferring 'virtinst-c_yhjtv8-initrd.gz' | 0 B 00:00 ... Allocating 'debian12.qcow2' | 0 B 00:00 ... Creating domain... | 0 B 00:00 Domain is still running. Installation may be in progress. You can reconnect to the console to complete the installation process. ``` We haven't specified the name of the VM (`--name`), the network (`--network`) to use, the location for the disk or its size (`--disk`), as well the RAM (`--memory`). It defaulted to `debian12` for the name. For the RAM and disk size, it uses defaults from its database. As for the network, it will use the `default` adapter, and it will store the disk in the `default`[storage pool](https://libvirt.org/storage.html), which is in `/var/lib/libvirt/images`. It starts by downloading the necessary files to start the installation, then runs it in the background as requested. ## Monitoring installation progress While not necessary, we can look at the console to see the progress: ```plaintext sudo virsh console debian12 ``` We can also continue with `virt-manager` instead. It should complete in a few minutes, then it will poweroff the system. It's a basic server with SSH, so we'll still need to adjust a few things such as setting the timezone, adding users, and providing SSH key for authentication. ## Accessing the system via SSH It's useful to have console access, but SSH is more practical. ### List running domains We can list the running virtual machines (aka ***domains***) with `sudo virsh list`: ```plaintext user@fedora:~$ sudo virsh list Id Name State ------------------------- 1 dev running 2 freebsd running 3 win11 running 4 spotify running ``` `debian12` is not present in the list, so it must be in another state. We can add the `--all` parameter to the command to list all the VM in any state: ```plaintext user@ubuntu:~$ sudo virsh list --all Id Name State ------------------------------------ 1 dev running 2 freebsd running 3 win11 running 4 spotify running - AI shut off - debian12 shut off - Kali shut off - storage shut off ``` It's shut off at this time. ### Start the domain ```plaintext user@ubuntu:~$ sudo virsh start debian12 Domain 'debian12' started ``` Let's give it a few seconds to boot so that it can get an IP address. ### Obtaining VM IP address Our VM got attached to the `default` network. We'll query the DHCP leases to figure out what IP address it got: ```plaintext Expiry Time MAC address Protocol IP address Hostname Client ID or DUID ------------------------------------------------------------------------------------------------------------------------------------------------ 2024-05-25 12:06:08 52:54:00:de:18:bb ipv4 192.168.100.168/24 - 01:52:54:00:12:18:aa 2024-05-25 12:25:07 52:54:00:de:98:bb ipv4 192.168.100.169/24 debian12 ff:00:12:18:aa:00:01:00:01:2d:e4:67:8b:52:54:00:12:18:aa 2024-05-25 12:19:29 52:54:00:a8:63:74 ipv4 192.168.100.181/24 pc 01:52:54:00:a8:68:75 2024-05-25 12:16:25 52:54:00:c4:28:fe ipv4 192.168.100.16/24 - 01:52:54:00:b5:28:ce 2024-05-25 12:16:56 52:54:00:32:05:09 ipv4 192.168.100.189/24 - 01:52:54:00:c2:83:63 ``` We can easily identify our `debian12`, it got 192.168.100.169. Now we're ready to SSH into it. ## A few things The big gotcha is that not all distributions are supported. We can list the ones that support the `--unattended` option using the following script (on Ubuntu, we need the `osinfo-db-tools` package): ```bash #!/bin/bash echo "Checking install scripts for each OS..." # List all OSes and their short IDs os_list=$(osinfo-query os) # Loop through each OS and check if it has an install script while IFS= read -r line; do # Extract the short ID and the full name of the OS short_id=$(echo "$line" | awk '{print $1}') name=$(echo "$line" | awk -F '|' '{print $2}') # Check if the OS has an install script if osinfo-install-script "$short_id" &> /dev/null; then echo "$name ($short_id) has an install script." fi done <<< "$os_list" ``` The database (containing the unattended installation scripts, URL locations, etc) gets updated once in a while, but we can also update it manually. Using the `nightly` option to get the most recent development version (`--latest` is a lesser adventurous option), it looks like this: ```bash osinfo-db-import --nightly ``` A bit more than a month after the release of Ubuntu 24.04 and Fedora 40, only Fedora 40 support was added. Furthermore, while a number of distributions have unattended installation, they don't always have an install tree URL. As an example, for Ubuntu, we have to go back all the way to 20.04 for the install tree URL to be in the database. Anything more recent than 20.04 doesn't have one available. However, if we have an install tree and provide its path (`--location`), it should be able to do the unattended installation.