Some systemd-specific code will (probably) be required soon

[lw]

I'd like to draw attention to this document:

http://www.freedesktop.org/wiki/Software/systemd/ControlGroupInterface/

from which I quote:

In the short-term future writing directly to the control group tree from applications should still be OK, as long as the Pax Control Groups [1] document is followed. In the medium-term future it will still be supported to alter/read individual attributes of cgroups directly, but no longer to create/delete cgroups without using the systemd API. In the longer-term future altering/reading attributes will also be unavailable to userspace applications, unless done via systemd's APIs (either D-Bus based IPC APIs or shared library APIs for passive operations).

I'm not aware of the current status of that document and of the plans it describes (whether they're abandoned, confirmed, already achieved, etc.) but, if those goals will be fulfilled, isolate won't be able to operate as it does now.

I know that some people don't agree with the attitude of systemd developers towards pushing for new standards and conventions (and neither do I, in this occasion) but systemd is now part of most Linux distributions (including Ubuntu, our favorite target), meaning we have to deal with it.

Finally, I'd like to express a personal opinion: isolate's use of cgroups is quite simple, in that it creates only a handful of cgroups that it keeps for its personal use, without any interaction with the rest of the system. Moreover, there seem to be very few pieces of software that use cgroups (at least that's what I've noticed in my experience) and systemd is probably the major one, also considering its role in setting up and organizing the system's hierarchy. I therefore consider it to be of value to "play along nicely" with systemd.

[1] http://www.freedesktop.org/wiki/Software/systemd/PaxControlGroups/