go's switch statement doesn't need an explicit break. Remove it where
that is the case and add a comment to indicate the purpose where the
removal would lead to an empty case.
Found with honnef.co/go/tools/cmd/staticcheck
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
The rootless cgroup manager acts as a noop for all set and apply
operations. It is just used for rootless setups. Currently this is far
too simple (we need to add opportunistic cgroup management), but is good
enough as a first-pass at a noop cgroup manager.
Signed-off-by: Aleksa Sarai <asarai@suse.de>
Delegate is only available in systemd >218, applying it for older systemd will
result in an error. Therefore we should check for it when testing systemd
properties.
Signed-off-by: Daniel, Dao Quang Minh <dqminh89@gmail.com>
No substantial code change.
Note that some style errors reported by `golint` are not fixed due to possible compatibility issues.
Signed-off-by: Akihiro Suda <suda.kyoto@gmail.com>
This is required because we manage some of the cgroups ourselves.
This recommendation came from talking with systemd devs about
some of the issues that we see when using the systemd cgroups driver.
Signed-off-by: Mrunal Patel <mrunalp@gmail.com>
Add some further (not critical, since Docker does this already)
validation to systemd slice names, to make sure users don't get cryptic
errors.
Signed-off-by: Aleksa Sarai <asarai@suse.com>
Rather than using '/' to denote hierarchy in slice names, systemd uses
'-' in an odd way. This results in runC incorrectly assuming that
certain kernel features are missing (and using inconsistent paths for
the cgroups not supported by systemd), because the "subsystem path" used
is not the one that systemd has created. Fix all of this by properly
expanding slice names.
Signed-off-by: Aleksa Sarai <asarai@suse.com>
Modify the memory cgroup code such that kmem is not managed by Set(), in
order to allow updating of memory constraints for containers by Docker.
This also removes the need to make memory a special case cgroup.
Signed-off-by: Aleksa Sarai <asarai@suse.com>
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.
One of the weird cases to deal with is systemd. Systemd sets some of the
cgroup configuration options, but not all of them. Because memory is a
special case, we need to explicitly set memory in the systemd Apply().
Otherwise, the rest can be safely re-applied in .Set() as usual.
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>
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>
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>
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>
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>
In some older kernels setting swappiness fails. This happens even
when nobody tries to configure swappiness from docker UI because
we would still get some default value from host config.
With this we treat -1 value as default value (set implicitly) and skip
the enforcement of swappiness.
However from the docker UI setting an invalid value anything other than
0-100 including -1 should fail. This patch enables that fix in docker UI.
without this fix container creation with invalid value succeeds with a
default value (60) which in incorrect.
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Tobias Klauser
Aleksa Sarai
Qiang Huang
xuxinkun
Derek Carr
Daniel Dao
Buddha Prakash
Seth Jennings
Mrunal Patel
Kenfe-Mickael Laventure
Akihiro Suda
Jessica Frazelle
Aleksa Sarai
Mrunal Patel
Jimmi Dyson
Michael Crosby
Alexander Morozov
Antonio Murdaca
Kir Kolyshkin
Raghavendra K T
unclejack