* Lets container@.service be activated by machines.target instead of
multi-user.target
According to the systemd manpages, all containers that are registered
by machinectl, should be inside machines.target for easy stopping
and starting container units altogether
* make sure container@.service and container.slice instances are
actually located in machine.slice
https://plus.google.com/112206451048767236518/posts/SYAueyXHeEX
See original commit: https://github.com/NixOS/systemd/commit/45d383a3b8
* Enable Cgroup delegation for nixos-containers
Delegate=yes should be set for container scopes where a systemd instance
inside the container shall manage the hierarchies below its own cgroup
and have access to all controllers.
This is equivalent to enabling all accounting options on the systemd
process inside the system container. This means that systemd inside
the container is responsible for managing Cgroup resources for
unit files that enable accounting options inside. Without this
option, units that make use of cgroup features within system
containers might misbehave
See original commit: https://github.com/NixOS/systemd/commit/a931ad47a8
from the manpage:
Turns on delegation of further resource control partitioning to
processes of the unit. Units where this is enabled may create and
manage their own private subhierarchy of control groups below the
control group of the unit itself. For unprivileged services (i.e.
those using the User= setting) the unit's control group will be made
accessible to the relevant user. When enabled the service manager
will refrain from manipulating control groups or moving processes
below the unit's control group, so that a clear concept of ownership
is established: the control group tree above the unit's control
group (i.e. towards the root control group) is owned and managed by
the service manager of the host, while the control group tree below
the unit's control group is owned and managed by the unit itself.
Takes either a boolean argument or a list of control group
controller names. If true, delegation is turned on, and all
supported controllers are enabled for the unit, making them
available to the unit's processes for management. If false,
delegation is turned off entirely (and no additional controllers are
enabled). If set to a list of controllers, delegation is turned on,
and the specified controllers are enabled for the unit. Note that
additional controllers than the ones specified might be made
available as well, depending on configuration of the containing
slice unit or other units contained in it. Note that assigning the
empty string will enable delegation, but reset the list of
controllers, all assignments prior to this will have no effect.
Defaults to false.
Note that controller delegation to less privileged code is only safe
on the unified control group hierarchy. Accordingly, access to the
specified controllers will not be granted to unprivileged services
on the legacy hierarchy, even when requested.
The following controller names may be specified: cpu, cpuacct, io,
blkio, memory, devices, pids. Not all of these controllers are
available on all kernels however, and some are specific to the
unified hierarchy while others are specific to the legacy hierarchy.
Also note that the kernel might support further controllers, which
aren't covered here yet as delegation is either not supported at all
for them or not defined cleanly.
"machine.target" doesn't actually exist, it's misspelled version
of "machines.target". However, the "systemd-nspawn@.service"
unit already has a default dependency on "machines.target"
