The services systemd-random-seed-save.service and
systemd-update-utmp-shutdown.service from systemd 203 don't work,
because they have a RequiresMountFor dependency on /var/lib and
/var/log. Such a dependency produces a cycle, causing systemd to drop
those services:
Fixing conflicting jobs by deleting job poweroff.target/stop
Deleting job systemd-poweroff.service/stop as dependency of job poweroff.target/stop
Deleting job umount.target/stop as dependency of job systemd-poweroff.service/stop
Deleting job -.mount/start as dependency of job umount.target/stop
Deleting job systemd-random-seed-save.service/start as dependency of job -.mount/start
Deleting job systemd-update-utmp-shutdown.service/start as dependency of job -.mount/start
Dropping the RequiresMountFor doesn't work either, because then
/var/... may have meen unmounted or remounted read-only.
Upstream systemd fixes this by doing the actual work from an ExecStop
action in an already-running service than conflicts with
shutdown.target. So I backported that here. The main consequence is
that wtmp shutdown records now get written properly.
The main lesson: shutdown.target is useless for pulling in services
during shutdown if they need to write anywhere.
You can now do a fast reboot (bypassing the BIOS, which may take
several minutes on servers) by running ‘systemctl kexec’.
Unfortunately the QEMU test for this is unreliable due to a QEMU bug
(it randomly crashes with a message like ‘Guest moved used index from
8 to 0’), so it's commented out.
Ensure permission bits are (re)set on each system activation with
explicit chmod call.
mkdir -m MODE PATH will only set the permission bits if PATH is
*created*, which means users that have old NixOS versions will continue
to have the old 700 permissions on /var/log/journal until they chmod
manually. With this commit the permissions will be set to 755 on system
activation.
This makes the system journal readable by users in the
systemd-journal, wheel and adm groups. It also allows users to read
their own journals.
Note that this doesn't change the permissions of existing journals.
Turns out that remote-fs-pre.target is not actually "wanted" anywhere,
so statd is not started before remote filesystems are mounted. But
remote filesystems do "want" network-online.target, so we can use that
to pull in statd and idmapd.
Not sure if this is really the right thing to do, but it works for
now. Background:
https://bugzilla.redhat.com/show_bug.cgi?id=787314http://hydra.nixos.org/build/5542230
"require" is a stronger version of "want",
and just like wantedBy allows you to specify this relation in reverse,
requiredBy does the same.
It may seem pointless to be able to specify these stronger relations in
reverse, because if something is really required, you would expect the
other unit to specify this himself.
However, this is still useful for virtual/automatic units (like
devices) that are created by systemd on demand and hence have no unit
file you can alter.
man logind.conf clearly states that the header is [Login] (no 'd').
Without this fix services.logind.extraConfig does not take effect
because logind ignores the invalidly named section.
So that we can customize systemd-logind in configuration.nix.
Example:
services.logind.extraConfig = "HandleLidSwitch=ignore";
See man logind.conf for available options.
EC2 instances don't have a console, so it's pointless to start
emergency mode if a mount fails. (This happened to me with an
encrypted filesystem where the key wasn't sent on time using "charon
send-keys".) Better to cross fingers and continue booting.
Also, symlink kbrequest.target to rescue.target as suggested by the
systemd.special manpage. This way, you can start a sulogin rescue
shell by pressing Alt+Up.
During a configuration switch, changed units are stopped in the old
configuration, then started in the new configuration (i.e. after
running the activation script and running "systemctl daemon-reload").
This ensures that services are stopped using the ExecStop/ExecStopPost
commands from the old configuration.
However, for some services it's undesirable to stop them; in
particular dhcpcd, which deconfigures its network interfaces when it
stops. This is dangerous when doing remote upgrades - usually things
go right (especially because the switch script ignores SIGHUP), but
not always (see 9aa69885f0). Likewise,
sshd should be kept running for as long as possible to prevent a
lock-out if the switch fails.
So the new option ‘stopIfChanged = false’ causes "systemctl restart"
to be used instead of "systemctl stop" followed by "systemctl start".
This is only proper for services that don't have stop commands. (And
it might not handle dependencies properly in some cases, but I'm not
sure.)
This is mainly useful for specifying mounts that depend on other
units. For example sshfs or davfs need network (and possibly
nameservices).
While systemd makes a distinction between local and remote
filesystems, this only works for in-kernel filesystems such as
nfs and cifs.
fuse-based filesystems (such as sshfs and davs) are classified as
local, so they fail without networking. By explicitly declaring these
mounts as full systemd units (as opposed to having systemd generate
them automatically from /etc/fstab), dependencies can be specified as
on every other unit.
In the future, we can probably port NixOS' filesystems handling to use
these native systemd.mount units and skip /etc/fstab altogether, but
this probably requires additional changes, such as starting systemd
even earlier during boot (stage 1).
Having all services with DefaultDependencies=yes depend on
local-fs.target is annoying, because some of those services might be
necessary to mount local filesystems. For instance, Charon's
send-keys feature requires sshd to be running in order to receive LUKS
encryption keys, which in turn requires dhcpcd, and so on. So we drop
this dependency (and swap.target as well for consistency). If
services require a specific mount, they should use RequiresMountsFor
in any case.
This has rendered my system unbootable, because I forgot to enable AUTOFS4 in my
custom kernel. In addition to AUTOFS4, this includes (hopefully) all other
kernel features needed by systemd, as listed in the README:
REQUIREMENTS:
Linux kernel >= 2.6.39
with devtmpfs
with cgroups (but it's OK to disable all controllers)
optional but strongly recommended: autofs4, ipv6
Autofs4 is not a requirement here, but in our case it turns out that the system
is not able to boot properly with a LUKS-enabled system (or at least not on _my_
system).
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Running agetty on ttyS0 interferes with the backdoor, which uses ttyS0
as its standard error. After agetty starts, writes to the stderr file
descriptor will return EIO (though doing "exec 2>/proc/self/fd/2" will
miracuously fix this).
http://hydra.nixos.org/build/3252782
‘systemd-vconsole-setup’ by default operates on /dev/tty0, the
currently active tty. Since it puts /dev/tty0 in Unicode or ASCII
mode, if the X server is currently active when it runs, keys such as
Alt-F4 won't reach the X server anymore. So use /dev/tty1 instead.
The triggers are just arbitrary strings that are included in the unit
under X-Restart-Triggers. The idea is that if they change between
reconfigurations, switch-to-configuration will restart the unit
because its store path changed. This is mostly useful for services
that implicitly depend on generated files in /etc. Thus you can say
restartTriggers = [ confFile ];
where ‘confFile’ is the derivation that generated the /etc file in
question.
For each statically configured interface, we now create a unit
‘<interface>-cfg.service’ which gets started as soon as the network
device comes up. Similarly, each bridge defined in
‘networking.bridges’ and virtual interface in ‘networking.interfaces’
is created by a service ‘<interface>.service’.
So if we have
networking.bridges.br0.interfaces = [ "eth0" "eth1" ];
networking.interfaces =
[ { name = "br0";
ipAddress = "192.168.1.1";
}
];
then there will be a unit ‘br0.service’ that depends on
‘sys-subsystem-net-devices-eth0.device’ and
‘sys-subsystem-net-devices-eth1.device’, and a unit ‘br0-cfg.service’
that depends on ‘sys-subsystem-net-devices-br0.device’.
