Lines Matching refs:in
21 comprehensive up-to-date information about all this, particular in light of the
28 This document then adds in the higher-level view from systemd.
37 with cgroups and systemd, in particular as they shine more light on the various
47 1. The **no-processes-in-inner-nodes** rule: this means that it's not permitted
53 both processes and children — which is used in particular to maintain kernel
64 your container manager creates and manages cgroups in the system's root cgroup
72 either cgroup v1 nor cgroup v2 (this is UNIX after all, in the general case
74 be in constant pain as various pieces of software will fight over cgroup
78 it's semantically broken in many ways, and in many cases doesn't actually do
80 kernel features in this area are only added to cgroup v2, and not cgroup v1
101 `/sys/fs/cgroup/unified/` that contains the cgroup v2 hierarchy. (Note that in
103 controllers are all mounted as separate hierarchies as in legacy mode,
115 Superficially, in legacy and hybrid modes it might appear that the parallel
117 systemd they are not: the hierarchies of all controllers are always kept in
118 sync (at least mostly: sub-trees might be suppressed in certain hierarchies if
120 hierarchies in sync means that the legacy and hybrid hierarchies are
122 to talk of one specific cgroup and actually mean the same cgroup in all
126 Note that in cgroup v2 the controller hierarchies aren't orthogonal, hence
127 thinking about them as orthogonal won't help you in the long run anyway.
130 `statfs()` on `/sys/fs/cgroup/`. If it reports `CGROUP2_SUPER_MAGIC` in its
131 `.f_type` field, then you are in unified mode. If it reports `TMPFS_MAGIC` then
132 you are either in legacy or hybrid mode. To distinguish these two cases, run
134 `CGROUP2_SUPER_MAGIC` you are in hybrid mode, otherwise not.
135 From a shell, you can check the `Type` in `stat -f /sys/fs/cgroup` and
140 The low-level kernel cgroups feature is exposed in systemd in three different
159 hence cannot really be defined fully in 'offline' concepts such as unit
207 takes place at a specific cgroup: in systemd there's a `Delegate=` property you
225 cgroups below it. Note however that systemd will do that only in the unified
226 hierarchy (in unified and hybrid mode) as well as on systemd's own private
227 hierarchy (in legacy and hybrid mode). It won't pass ownership of the legacy
229 in cgroup v1 (as a limitation of the kernel), hence systemd won't facilitate
261 newer in combination with systemd 251 and newer.
276 (Also note, if you intend to use "threaded" cgroups — as added in Linux 4.14 —,
298 or services you make it possible to run cgroup-enabled programs in your
308 operations as in a. The main benefit of this: this way you let the system
319 interest in integration with the rest of the system, then this is a valid
321 manager daemon. Then figure out the cgroup systemd placed your daemon in:
323 *no-processes-in-inner-nodes* rule however: you have to move your main
325 start further processes in any of your sub-cgroups.
334 big scope that contains all your managed processes in one.
339 option #2 in that case however, as you can simply set `Delegate=` in your
343 you are started in, and everything below it, whatever that might be. That said,
367 mounts all controller hierarchies it finds available in the kernel). If you
370 replicate the cgroup hierarchies of the other controllers in them too however,
372 care. Replicating the cgroup hierarchies in those unsupported controllers would
373 mean replicating the full cgroup paths in them, and hence the prefixing
376 up after you in the hierarchies it manages: if your daemon goes down, its
379 started. This is not the case however in the hierarchies systemd doesn't
381 cgroups in them — from previous runs, and be extra careful with them as they
400 it is running in and take possession of it. It won't interfere with any cgroup
401 outside of the sub-tree it was invoked in. Use of `CLONE_NEWCGROUP` is hence
405 of the root cgroup you pass to it *in* *full*, i.e. it will not only
409 insist on managing the delegated cgroup tree's top-level attributes. Or in
412 the specific cgroup in both cases. A container manager that is itself a payload
414 instead hence needs to insert an extra level in the hierarchy in between, so
415 that the systemd on the host and the one in the container won't fight for the
417 no-processes-in-inner-cgroups rule, see below.
427 1. ⚡ If you go for implementation option 1a or 1b (as in the list above), then
430 running in that unit will be some kind of executor program, which will in
435 of the no-process-in-inner-nodes rule, your executor needs to migrate itself
437 want a two-pronged approach: below the cgroup you got started in, you want
438 one cgroup maybe called `supervisor/` where your manager runs in and then
442 suitable as UNIX file names, and that they live in the same namespace as the
447 attribute in cgroup v1, and your `mkdir()` will hence fail with `EEXIST`. In
455 cgroups you haven't set `Delegate=` in. Specifically: �� don't create your
459 as you like. Seriously, if you create cgroups directly in the cgroup root,
462 2. �� Don't attempt to set `Delegate=` in slice units, and in particular not in
467 attributes of cgroups you created in your own delegated sub-tree, but the
484 may change in future versions. This means: it's best to avoid implementing a
485 local logic of translating cgroup paths to slice/scope/service names in your