Some units set KillMode=none to survive the initrd→rootfs transition. We
cannot remove their cgroups, but that shouldn't really be considered an
issue, so let's downgrade the error message.
Replace the very generic cgroup hookup with a much simpler one. With
this change only the high-level cgroup settings remain, the ability to
set arbitrary cgroup attributes is removed, so is support for adding
units to arbitrary cgroup controllers or setting arbitrary paths for
them (especially paths that are different for the various controllers).
This also introduces a new -.slice root slice, that is the parent of
system.slice and friends. This enables easy admin configuration of
root-level cgrouo properties.
This replaces DeviceDeny= by DevicePolicy=, and implicitly adds in
/dev/null, /dev/zero and friends if DeviceAllow= is used (unless this is
turned off by DevicePolicy=).
- This changes all logind cgroup objects to use slice objects rather
than fixed croup locations.
- logind can now collect minimal information about running
VMs/containers. As fixed cgroup locations can no longer be used we
need an entity that keeps track of machine cgroups in whatever slice
they might be located. Since logind already keeps track of users,
sessions and seats this is a trivial addition.
- nspawn will now register with logind and pass various bits of metadata
along. A new option "--slice=" has been added to place the container
in a specific slice.
- loginctl gained commands to list, introspect and terminate machines.
- user.slice and machine.slice will now be pulled in by logind.service,
since only logind.service requires this slice.
In order to prepare for the kernel cgroup rework, let's introduce a new
unit type to systemd, the "slice". Slices can be arranged in a tree and
are useful to partition resources freely and hierarchally by the user.
Each service unit can now be assigned to one of these slices, and later
on login users and machines may too.
Slices translate pretty directly to the cgroup hierarchy, and the
various objects can be assigned to any of the slices in the tree.
Containers will now carry a label (normally derived from the root
directory name, but configurable by the user), and the container's root
cgroup is /machine/<label>. This label is called "machine name", and can
cover both containers and VMs (as soon as libvirt also makes use of
/machine/).
libsystemd-login can be used to query the machine name from a process.
This patch also includes numerous clean-ups for the cgroup code.
This allows clients to put inotify watches on these trees to watch for
state changes, without having to wait until these dirs are created.
This introduces the new top-level /machine cgroup dir as canonical
location where OS containers and VMs shall be located (as discussed with
the libvirt folks).
Note: I did s/MANAGER/SYSTEMD/ everywhere, even though it makes the
patch quite verbose. Nevertheless, keeping MANAGER prefix in some
places, and SYSTEMD prefix in others would just lead to confusion down
the road. Better to rip off the band-aid now.
also a number of minor fixups and bug fixes: spelling, oom errors
that didn't print errors, not properly forwarding error codes,
few more consistency issues, et cetera
glibc/glib both use "out of memory" consistantly so maybe we should
consider that instead of this.
Eliminates one string out of a number of binaries. Also fixes extra newline
in udev/scsi_id
The kernel will only notify us of cgroups running empty if no subcgroups
exist anymore. Hence make sure we don't leave our own control/ subcgroup
around longer than necessary.
https://bugzilla.redhat.com/show_bug.cgi?id=818381
Previously, we were brutally and onconditionally killing all processes
in a service's cgroup before starting the service anew, in order to
ensure that StartPre lines cannot be misused to spawn long-running
processes.
On logind-less systems this has the effect that restarting sshd
necessarily calls all active ssh sessions, which is usually not
desirable.
With this patch control processes for a service are placed in a
sub-cgroup called "control/". When starting a service anew we simply
kill this cgroup, but not the main cgroup, in order to avoid killing any
long-running non-control processes from previous runs.
https://bugzilla.redhat.com/show_bug.cgi?id=805942
We finally got the OK from all contributors with non-trivial commits to
relicense systemd from GPL2+ to LGPL2.1+.
Some udev bits continue to be GPL2+ for now, but we are looking into
relicensing them too, to allow free copy/paste of all code within
systemd.
The bits that used to be MIT continue to be MIT.
The big benefit of the relicensing is that closed source code may now
link against libsystemd-login.so and friends.
