It is vital to loudly fail when a user attempts to set a cgroup limit
(rather than using the system default). Otherwise the user will assume
they have security they do not actually have. This mirrors the original
Apply() (that would set cgroup configs) semantics.
Signed-off-by: Aleksa Sarai <asarai@suse.com>
Apply and Set are two separate operations, and it doesn't make sense to
group the two together (especially considering that the bootstrap
process is added to the cgroup as well). The only exception to this is
the memory cgroup, which requires the configuration to be set before
processes can join.
Signed-off-by: Aleksa Sarai <asarai@suse.com>
Add support for the pids cgroup controller to libcontainer, a recent
feature that is available in Linux 4.3+.
Unfortunately, due to the init process being written in Go, it can spawn
an an unknown number of threads due to blocked syscalls. This results in
the init process being unable to run properly, and thus small pids.max
configs won't work properly.
Signed-off-by: Aleksa Sarai <asarai@suse.com>
This allows us to distinguish cases where a container
needs to just join the paths or also additionally
set cgroups settings. This will help in implementing
cgroupsPath support in the spec.
Signed-off-by: Mrunal Patel <mrunalp@gmail.com>
The former cgroup entry is confusing, separate it to parent
and name.
Rename entry `c` to `config`.
Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
'parent' function is confusing with parent cgroup, it's actually
parent path, so rename it to parentPath.
The name 'data' is too common to be identified, rename it to cgroupData
which is exactly what it is.
Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
We have a rule that for optional cgroups, don't fail if some
of them are not mounted, but we want it fail hard when a
user specifies an option and we are unable to fulfill the
request.
Memory cgroup should also follow this rule.
Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Also add cpuset as the first in the list to address issues setting the
pid in any cgroup before the cpuset is populated.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
It can avoid unnecessary task migrataion, see this scenario:
- container init task is on cpu 1, and we assigned it to cpu 1,
but parent cgroup's cpuset.cpus=2
- we created the cgroup dir and inherited cpuset.cpus from parent as 2
- write container init task's pid to cgroup.procs
- [it's possibile the container init task migrated to cpu 2 here]
- set cpuset.cpus as assigned to cpu 1
- [the container init task has to be migrated back to cpu 1]
So we should set cpuset.cpus and cpuset.mems before writing pids
to cgroup.procs to aviod such problem.
Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
This allows getting the path to the subsystem and so is subsequently
used in EnterPid by an exec process.
Signed-off-by: Mrunal Patel <mrunalp@gmail.com>
This is meant to be used in retrieving the paths so an exec
process enters all the cgroup paths correctly.
Signed-off-by: Mrunal Patel <mrunalp@gmail.com>
Godeps: Vendor opencontainers/specs 96bcd043aa
Fix a bug where it's impossible to pass multiple devices to blkio
cgroup controller files. See https://github.com/opencontainers/runc/issues/274
Signed-off-by: Antonio Murdaca <runcom@linux.com>
Bug was introduced in #250
According to: http://man7.org/linux/man-pages/man5/proc.5.html
36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 - ext3 /dev/root rw,errors=continue
(1)(2)(3) (4) (5) (6) (7) (8) (9) (10) (11)
...
(7) optional fields: zero or more fields of the form
"tag[:value]".
The 7th field is optional. We should skip it when parsing mount info.
Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
TL;DR: check for IsExist(err) after a failed MkdirAll() is both
redundant and wrong -- so two reasons to remove it.
Quoting MkdirAll documentation:
> MkdirAll creates a directory named path, along with any necessary
> parents, and returns nil, or else returns an error. If path
> is already a directory, MkdirAll does nothing and returns nil.
This means two things:
1. If a directory to be created already exists, no error is
returned.
2. If the error returned is IsExist (EEXIST), it means there exists
a non-directory with the same name as MkdirAll need to use for
directory. Example: we want to MkdirAll("a/b"), but file "a"
(or "a/b") already exists, so MkdirAll fails.
The above is a theory, based on quoted documentation and my UNIX
knowledge.
3. In practice, though, current MkdirAll implementation [1] returns
ENOTDIR in most of cases described in #2, with the exception when
there is a race between MkdirAll and someone else creating the
last component of MkdirAll argument as a file. In this very case
MkdirAll() will indeed return EEXIST.
Because of #1, IsExist check after MkdirAll is not needed.
Because of #2 and #3, ignoring IsExist error is just plain wrong,
as directory we require is not created. It's cleaner to report
the error now.
Note this error is all over the tree, I guess due to copy-paste,
or trying to follow the same usage pattern as for Mkdir(),
or some not quite correct examples on the Internet.
[1] https://github.com/golang/go/blob/f9ed2f75/src/os/path.go
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Sometimes subsystem can be mounted to path like "subsystem1,subsystem2",
so we need to handle this.
Signed-off-by: Alexander Morozov <lk4d4@docker.com>
This is needed because for nested containers cgroups. Without this patch
they creating unnecessary intermediate cgroup like:
/sys/fs/cgroup/memory/system.slice/docker-9409d9f0b68fb9e9d7d532d5b3f35e7c7f9cca1312af392ae3b28436f1f2998f.scope/system.slice/docker-9409d9f0b68fb9e9d7d532d5b3f35e7c7f9cca1312af392ae3b28436f1f2998f.scope/docker/908ebcc9c13584a14322ec070bd971e0de62f126c0cd95c079acdb99990ad3a3
It is because in /proc/self/cgroup we see paths from host, and they don't
exist in container.
Signed-off-by: Alexander Morozov <lk4d4@docker.com>
Mrunal Patel
Aleksa Sarai
Qiang Huang
Mrunal Patel
David Calavera
Doug Davis
John Howard
Michael Crosby
Alexander Morozov
Antonio Murdaca
Alexander Morozov
Andrey Vagin
Shijiang Wei
Kir Kolyshkin