Commit Graph

9 Commits

Author SHA1 Message Date
Eelco Dolstra
9ee30cd9b5 Add support for lightweight NixOS containers
You can now say:

  systemd.containers.foo.config =
    { services.openssh.enable = true;
      services.openssh.ports = [ 2022 ];
      users.extraUsers.root.openssh.authorizedKeys.keys = [ "ssh-dss ..." ];
    };

which defines a NixOS instance with the given configuration running
inside a lightweight container.

You can also manage the configuration of the container independently
from the host:

  systemd.containers.foo.path = "/nix/var/nix/profiles/containers/foo";

where "path" is a NixOS system profile.  It can be created/updated by
doing:

  $ nix-env --set -p /nix/var/nix/profiles/containers/foo \
      -f '<nixos>' -A system -I nixos-config=foo.nix

The container configuration (foo.nix) should define

  boot.isContainer = true;

to optimise away the building of a kernel and initrd.  This is done
automatically when using the "config" route.

On the host, a lightweight container appears as the service
"container-<name>.service".  The container is like a regular NixOS
(virtual) machine, except that it doesn't have its own kernel.  It has
its own root file system (by default /var/lib/containers/<name>), but
shares the Nix store of the host (as a read-only bind mount).  It also
has access to the network devices of the host.

Currently, if the configuration of the container changes, running
"nixos-rebuild switch" on the host will cause the container to be
rebooted.  In the future we may want to send some message to the
container so that it can activate the new container configuration
without rebooting.

Containers are not perfectly isolated yet.  In particular, the host's
/sys/fs/cgroup is mounted (writable!) in the guest.
2013-11-27 17:14:10 +01:00
Eelco Dolstra
89b1dd8dde Fix environment.checkConfigurationOptions
This requires delaying the declaredness check until later, otherwise
we get an infinite recursion querying
environment.checkConfigurationOptions.
2013-10-29 16:18:23 +01:00
Eelco Dolstra
3115addf4c Fix nixos-option
In particular, it no longer produces an "infinite recursion" error
when run with no arguments.
2013-10-28 22:45:58 +01:00
Eelco Dolstra
f4a418761b Check for undeclared options 2013-10-28 22:45:56 +01:00
Eelco Dolstra
0e333688ce Big cleanup of the NixOS module system
The major changes are:

* The evaluation is now driven by the declared options.  In
  particular, this fixes the long-standing problem with lack of
  laziness of disabled option definitions.  Thus, a configuration like

    config = mkIf false {
      environment.systemPackages = throw "bla";
    };

  will now evaluate without throwing an error.  This also improves
  performance since we're not evaluating unused option definitions.

* The implementation of properties is greatly simplified.

* There is a new type constructor "submodule" that replaces
  "optionSet".  Unlike "optionSet", "submodule" gets its option
  declarations as an argument, making it more like "listOf" and other
  type constructors.  A typical use is:

    foo = mkOption {
      type = type.attrsOf (type.submodule (
        { config, ... }:
        { bar = mkOption { ... };
          xyzzy = mkOption { ... };
        }));
    };

  Existing uses of "optionSet" are automatically mapped to
  "submodule".

* Modules are now checked for unsupported attributes: you get an error
  if a module contains an attribute other than "config", "options" or
  "imports".

* The new implementation is faster and uses much less memory.
2013-10-28 22:45:55 +01:00
Eelco Dolstra
8f4c5b05d5 Add a way to define obsolete options that have no replacement 2013-10-23 20:08:22 +02:00
Eelco Dolstra
a2600b7bc3 Terrible backward compatibility hack 2013-10-11 13:36:09 +02:00
Eelco Dolstra
31203732b3 Update the release expressions and the channel generators 2013-10-10 13:28:22 +02:00
Eelco Dolstra
5c1f8cbc70 Move all of NixOS to nixos/ in preparation of the repository merge 2013-10-10 13:28:20 +02:00