Scripts to create a VM image using virt-builder.
Pre-requisites: virt-builder (via libguestfs-tools), Qemu and a public key in ~/.ssh/id_rsa.pub.
Build a VM and run it:
$ ./run.sh
Wait for it to finish and start the VM. In another terminal you can SSH in as the user "builder":
$ ssh builder@192.168.2.19 -p 2222
builder@kvm$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04 LTS
Release: 18.04
Codename: bionic
NOTE: you need a non-loopback address of localhost.
You can login with just a hostname if you configure that stuff in ~/.ssh/config:
Host qemu
HostName 192.168.2.19
Port 2222
User builder
then just ssh qemu. This is useful when using the remote extension in VS Code.
Using Nix
The example configuration installed Nix on top of the base Ubuntu. So you can use that to control dependencies in the runtime environmemt. E.g.
$ git
Command 'git' not found, but can be installed with:
sudo apt install git
$ nix-shell -p git
[nix-shell:~]$ git
usage: git [--version] [--help] [-C <path>] [-c <name>=<value>]
[--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]
[-p | --paginate | -P | --no-pager] [--no-replace-objects] [--bare]
[--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]
<command> [<args>]
...
Docker
You can dockerize the qemu snapshot (see Dockerfile included - assumes that you have created a snapshot in the disk.qcow). It doesn't start very fast though, and you have to run it --privileged.