It's only needed during early boot (in fact, it's probably not needed
at all on NixOS). Restarting it is expensive because it does a sync()
of the root file system.
systemd escaping rules translate this into a string containing '\'
which is treated by some code paths as quoted, and by others as unquoted
causing the affected units to fail.
Restarting user@ instances is bad because it causes all user services
(such as ssh-agent.service) to be restarted. Maybe one day we can have
switch-to-configuration restart user units in a fine-grained way, but
for now we should just ignore user systemd instances.
Backport: 14.04
If /boot is a btrfs subvolume, it will be on a different device than /
but not be at the root from grub's perspective. This should be fixed in
a nicer way by #2449, but that can't go into 14.04.
This reverts commit 6eaced3582. Doesn't
work very well, e.g. if you actually have the FUSE module loaded. And
in any case it's already fixed in NixOps.
These fail to mount if you don't have the appropriate kernel support,
and this confuses NixOps' ‘check’ command. We should teach NixOps not
to complain about non-essential mount points, but in the meantime it's
better to turn them off.
This used to work with systemd-nspawn 203, because it bind-mounted
/etc/resolv.conf (so openresolv couldn't overwrite it). Now it's just
copied, so we need some special handling.
With ‘systemd.user.units’ and ‘systemd.user.services’, you can specify
units used by per-user systemd instances. For example,
systemd.user.services.foo =
{ description = "foo";
wantedBy = [ "default.target" ];
serviceConfig.ExecStart = "${pkgs.foo}/bin/foo";
};
declares a unit ‘foo.service’ that gets started automatically when the
user systemd instance starts, and is stopped when the user systemd
instance stops.
Note that there is at most one systemd instance per user: it's created
when a user logs in and there is no systemd instance for that user
yet, and it's removed when the user fully logs out (i.e. has no
sessions anymore). So if you're simultaneously logged in via X11 and a
virtual console, you get only one copy of foo.
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.
This allows specifying rules for systemd-tmpfiles.
Also, enable systemd-tmpfiles-clean.timer so that stuff is cleaned up
automatically 15 minutes after boot and every day, *if* you have the
appropriate cleanup rules (which we don't have by default).
This creates static device nodes such as /dev/fuse or
/dev/snd/seq. The kernel modules for these devices will be loaded on
demand when the device node is opened.
This prevents insidious errors once systemd begins handling the unit. If
the unit is loaded at boot, any errors of this nature are logged to the
console before the journal service is running. This makes it very hard
to diagnose the issue. Therefore, this assertion helps guarantee the
mistake is not made.
