Installation of software from NGIpkgs currently requires Nix flakes to be enabled.
The example config in this repo is installing the default module from NGIpkgs, which contains all packages from the repo, as well as a module for one of the projects from NGIpkgs (Vula) and the minimal config to enable it in the configuration.nix. More info on installing software from NGIpkgs is also available in the readme of that repo.
After cloning this repo and entering its directory, run this command to build a NixOS system for a VM:
nix build .#nixosConfigurations.myMachine.config.system.build.vm
Before starting the VM, run this command to configure QEMU networking to allow logging into its VMs through SSH:
export QEMU_NET_OPTS="hostfwd=tcp::2221-:22"
If necessary, additional networking options could also be configured here, such as forwarding port 80 for a web app, for example.
Now run the script that has been built to boot the NixOS VM in QEMU:
./result/bin/run-nixos-vm
QEMU will open its own terminal window that shows the boot log. It is possible to login via this terminal, but the UX will usually be better with a regular SSH login (the default password is simply password):
ssh -oUserKnownHostsFile=/dev/null -oStrictHostKeyChecking=no user@localhost -p 2221