This project combines NixOS with Lima to provide reproducible NixOS deployments on MacOS with aarch64 architecture.
nix run github:ciderale/nixos-lima start
The above command boots a VM (named mynixos) using lima and deploys an NixOS configuration.
The default configuration includes docker engine and adds some default volume mounts.
The default nixos-lima configuration includes a docker installation. On VM
creation, nixos-lima also generates a shell script ~/.lima/mynixos.shrc to setup
the DOCKER_HOST and CONTAINER_HOST variable and add docker to your PATH.
You could add this to your .zprofile startup script for example.
In addition to lima-vm.io's port forwarding, nixos-lima can listens to the
docker event stream and provide port mapping more promptly than via polling.
nix run github:ciderale/nixos-lima portmapperd
The subcommand nix run github:ciderale/nixos-lima full combines start
and portmapperd in one. Stopping full with ctrl-c currently also stops
the virtual machine (unless it was already running).
You can extend the system configurations by pointing the NIXOS_LIMA_IMPURE_CONFIG environment variable to additional configuration files. The configuration includes all nixos options as well as the lima-vm configurations.
For example, the following configuration defines cpu/memory/disk size, additional mount locations from host to guest, and a docker registry mirror.
{
lima.settings = {
cpus = 8;
memory = "8GB";
disk = "60GB";
mounts = [ { location = "/host/folder/data"; mountPoint = "/data"; } ];
};
virtualisation.docker.daemon.settings.registry-mirrors = [ "https://xxx.xxx.xxx" ];
}
For more examples see "example/lima-settings.nix". It's worth noting that the options
under lima.settings correspond to lima templates and are used to the generate the
lima.yaml configuration. Moreover, the mount location must exist or the vm does
not start.
Changes are applied by re-running nixos-lima start.
NIXOS_LIMA_IMPURE_CONFIG=configuration.nix nix run github:ciderale/nixos-lima start
Note that changes to lima.settings result in a restart of the VM for those
changes to take effect. Normal nixos options changes are applied by means of
nixos-rebuild switch and don't require a VM restart. nixos-lima takes care
of the entire process.
Technically, the referenced configuration files are merged into the existing
configuration using the nix modules { imports = [ ... ]; } expression.
Multiple files may be referenced (separated by comma, e.g., NIXOS_LIMA_IMPURE_CONFIG=sizing.nix,mounts.nix
and each file may be an absolute path or relative to the current working directory.
More advanced configuration are better versioned explicitly using git. The
nixos-lima repository provides a nix flake template to start building the own
configuration. This approach is more flexible and allows to remove configuration
present in the example configuration.
# create a new repository to track your changes
cd some/path && mkdir mynixos && cd mynixos
nix flake init -t github:ciderale/nixos-lima
# deploy (and update) the configuration
nix run .#nixos-lima -- mynixos start
# get shell access to your machine
nix run .#nixos-lima -- mynixos ssh
As the name suggests, nixos-lima uses lima-vm.io as its underlying
virtualisation system. nixos-lima also benefits from the port- and
volume-mapping functionality provided by lima. Configuration in lima is done
via yaml templates and the linux vm is setup using cloud-init scripts.
In contrast, nixos-lima has a minimal cloud-init setup and instead relies on
NixOS configurations. NixOS provides a modular configuration system with many
pre-configured services. Moreover, NixOS generates highly reproducible
deployments.
kasuboski/nixos-lima also aims for running nixos on lima, hence the same
name. A key difference is how the two projects bootstrap a system.
kasuboski/nixos-lima uses the nixos-generator project to build an initial
image. This approach requires a linux system running nix. For example, a
lima-vm can be used with cloud-init script to setup nix. A benefit of this
is that the generated image can be reused multiple times.
In contrast, nixos-lima uses
nixos-anywhere to deploy
NixOS onto a freshly started lima-vm. In other words, instead of starting a vm
to build an image, which is then used for a second vm, nixos-lima starts one
vm and overwrites that system with the nixos configuration.
Moreover, nixos-lima integrates the lima-vm configuration into the NixOS module
system and provides a unified configuration experience.