If you define a unit, and either systemd or a package in
systemd.packages already provides that unit, then we now generate a
file /etc/systemd/system/<unit>.d/overrides.conf. This makes it
possible to use upstream units, while allowing them to be customised
from the NixOS configuration. For instance, the module nix-daemon.nix
now uses the units provided by the Nix package. And all unit
definitions that duplicated upstream systemd units are finally gone.
This makes the baseUnit option unnecessary, so I've removed it.
Using pkgs.lib on the spine of module evaluation is problematic
because the pkgs argument depends on the result of module
evaluation. To prevent an infinite recursion, pkgs and some of the
modules are evaluated twice, which is inefficient. Using ‘with lib’
prevents this problem.
This reverts commit b792394119.
Starting the manual on tty8 was intended as a convenience during
installation, not as a general purpose thing. In fact, given that w3m
runs as root, this is highly insecure!
This has the nice side-effect of making gpsd actually run!
Old behaviour (debugLevel=2):
systemd[1]: gpsd.service holdoff time over, scheduling restart.
systemd[1]: Stopping GPSD daemon...
systemd[1]: Starting GPSD daemon...
systemd[1]: gpsd.service start request repeated too quickly, refusing to start.
systemd[1]: Failed to start GPSD daemon.
systemd[1]: Unit gpsd.service entered failed state.
New behaviour (debugLevel=2):
gpsd[945]: gpsd: launching (Version 2.95)
systemd[1]: Started GPSD daemon.
gpsd[945]: gpsd: listening on port 2947
gpsd[945]: gpsd: running with effective group ID 27
gpsd[945]: gpsd: running with effective user ID 23
gpsd[945]: gpsd: stashing device /dev/ttyUSB0 at slot 0
Previously changing the value of certain options in configuration.nix
would cause the manual to be regenerated, because some option defaults
depend on the configuration. This is undesirable because rebuilding
the manual is kind of slow. So now the manual reflects an empty
configuration.
The downside is that this requires another call to fixMergeModules,
which adds about 14% to evaluation time. Probably worth it.
Suggested by Marc Weber. Fixes#1059.
Generate /etc/nix.machines only if buildMachines is not empty. Thus,
if you want to manage /etc/nix.machines in some other way, you can set
nix.distributedBuilds to true but not set nix.buildMachines.
