This is aimed at solving the problem of cgroup v2 memory controller
behavior which is not compatible with that of cgroup v1.
In cgroup v1, if the new memory limit being set is lower than the
current usage, setting the new limit fails.
In cgroup v2, same operation succeeds, and the container is OOM killed.
Introduce a new setting, memory.checkBeforeUpdate, and use it to mimic
cgroup v1 behavior.
Note that this is not 100% reliable because of TOCTOU, but this is the
best we can do.
Add some test cases.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Runc parses cpuset range to bits in the case of cgroup v2 + systemd as cgroup driver.
The byte order representation differs from systemd expectation, which will set
different cpuset range in systemd transient unit if the length of parsed byte array exceeds one.
# cat config.json
...
"resources": {
...
"cpu": {
"cpus": "10-23"
}
},
...
# runc --systemd-cgroup run test
# cat /run/systemd/transient/runc-test.scope.d/50-AllowedCPUs.conf
# This is a drop-in unit file extension, created via "systemctl set-property"
# or an equivalent operation. Do not edit.
[Scope]
AllowedCPUs=0-7 10-15
The cpuset.cpus in cgroup will also be set to wrong value after reloading systemd manager configuration.
# systemctl daemon-reload
# cat /sys/fs/cgroup/system.slice/runc-test.scope/cpuset.cpus
0-7,10-15
Signed-off-by: seyeongkim <seyeong.kim@canonical.com>
Signed-off-by: Chengen, Du <chengen.du@canonical.com>
This is a forward port of https://github.com/opencontainers/runc/pull/3620
The original code depended on the origin filesystem to have
/dev/{block,char} populated. This is done by udev normally and while is
very common non-containerized systemd installs, it's very easy to start
systemd in a container created by runc itself and not have
/dev/{block,char} populated. When this occurs, the following error
output is observed:
$ docker run hello-world
docker: Error response from daemon: failed to create shim task: OCI runtime create failed: runc create failed: unable to start container process: error during container init: error reopening /dev/null inside container: open /dev/null: operation not permitted: unknown.
/dev/null can't be opened because it was not added to the
deviceAllowList, as there was no /dev/char directory. The change here
utilizes the fact that when sysfs in in use, there is a
/sys/dev/{block,char} that is kernel maintained that we can check.
Signed-off-by: Evan Phoenix <evan@phx.io>
It's more idiomatic Go to define interfaces on the receiver, and constructors to
return concrete types.
This patch changes various constructors to return a concrete type, with the
exceptions of NewWithPaths, which needs the abstraction as it switches between
implementations.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
A regression reported for runc v1.1.3 says that "runc exec -t" fails
after doing "systemctl daemon-reload":
> exec failed: unable to start container process: open /dev/pts/0: operation not permitted: unknown
Apparently, with commit 7219387eb7 we are no longer adding
"DeviceAllow=char-pts rwm" rule (because os.Stat("char-pts") returns
ENOENT).
The bug can only be seen after "systemctl daemon-reload" because runc
also applies the same rules manually (by writing to devices.allow for
cgroup v1), and apparently reloading systemd leads to re-applying the
rules that systemd has (thus removing the char-pts access).
The fix is to do os.Stat only for "/dev" paths.
Also, emit a warning that the path was skipped. Since the original idea
was to emit less warnings, demote the level to debug.
Note this also fixes the issue of not adding "m" permission for block-*
and char-* devices.
A test case is added, which reliably fails before the fix
on both cgroup v1 and v2.
Fixes: https://github.com/opencontainers/runc/issues/3551
Fixes: 7219387eb7
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Since Go 1.19, godoc recognizes lists, code blocks, headings etc. It
also reformats the sources making it more apparent that these features
are used.
Fix a few places where it misinterpreted the formatting (such as
indented vs unindented), and format the result using the gofumpt
from HEAD, which already incorporates gofmt 1.19 changes.
Some more fixes (and enhancements) might be required.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
systemd emits very loud warnings when the path specified doesn't exist
(which can be the case for some of our default rules). We don't need the
ruleset we give systemd to be completely accurate (we discard some kinds
of wildcard rules anyway) so we can safely skip adding these.
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
These are only used from inside the package, and we don't want them to
be public.
The only two methods left are Enable and Disable.
While at it, fix or suppress found lint-extra warnings.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This commit separates the functionality of setting cgroup device
rules out of libct/cgroups to libct/cgroups/devices package. This
package, if imported, sets the function variables in libct/cgroups and
libct/cgroups/systemd, so that a cgroup manager can use those to manage
devices. If those function variables are nil (when libct/cgroups/devices
are not imported), a cgroup manager returns the ErrDevicesUnsupported
in case any device rules are set in Resources.
It also consolidates the code from libct/cgroups/ebpf and
libct/cgroups/ebpf/devicefilter into libct/cgroups/devices.
Moved some tests in libct/cg/sd that require device management to
libct/sd/devices.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This moves the functionality related to devices, SkipDevices, and
SkipFreezeOnSet to a separate file, in preparation for the next commit.
No code changes.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Looking through git blame, this was added by commit 9fac18329
aka "Initial commit of runc binary", most probably by mistake.
Obviously, a container should not have access to tun/tap device, unless
it is explicitly specified in configuration.
Now, removing this might create a compatibility issue, but I see no
other choice.
Aside from the obvious misconfiguration, this should also fix the
annoying
> Apr 26 03:46:56 foo.bar systemd[1]: Couldn't stat device /dev/char/10:200: No such file or directory
messages from systemd on every container start, when runc uses systemd
cgroup driver, and the system runs an old (< v240) version of systemd
(the message was presumably eliminated by [1]).
[1] https://github.com/systemd/systemd/pull/10996/commits/d5aecba6e0b7c73657c4cf544ce57289115098e7
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
In case statfs("/sys/fs/cgroup/unified") fails with any error other
than ENOENT, current code panics. As IsCgroup2HybridMode is called from
libcontainer/cgroups/fs's init function, this means that any user of
libcontainer may panic during initialization, which is ugly.
Avoid panicking; instead, do not enable hybrid hierarchy support and
report the error (under debug level, not to confuse anyone).
Basically, replace the panic with "turn off hybrid mode support"
(which makes total sense since we were unable to statfs its root).
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Since LinuxFactory has become the means to specify containers state
top directory (aka --root), and is only used by two methods (Create
and Load), it is easier to pass root to them directly.
Modify all the users and the docs accordingly.
While at it, fix Create and Load docs (those that were originally moved
from the Factory interface docs).
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Apparently, "systemctl --user --no-pager show-environment" is useless
without DBUS_SESSION_BUS_ADDRESS or XDG_RUNTIME_DIR set:
$ echo $DBUS_SESSION_BUS_ADDRESS, $XDG_RUNTIME_DIR
unix:path=/run/user/1000/bus, /run/user/1000
$ systemctl --user --no-pager show-environment | grep DBUS_SESS
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
$ unset DBUS_SESSION_BUS_ADDRESS
$ systemctl --user --no-pager show-environment | grep DBUS_SESS
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
$ unset XDG_RUNTIME_DIR
$ systemctl --user --no-pager show-environment | grep DBUS_SESS
Failed to connect to bus: $DBUS_SESSION_BUS_ADDRESS and $XDG_RUNTIME_DIR not defined (consider using --machine=<user>@.host --user to connect to bus of other user)
So, it does not make sense to try it to get the address.
Also, it does not make sense to suggest "systemctl --user start dbus"
either, for the same reason, so remove that suggestion from the error
message text.
Since DBUS_SESSION_BUS_ADDRESS environment variable, on which the code
relies, is et by dbus-run-session (or dbus-launch, or something similar
that is supposed to be run during the login process), add a suggestion
to re-login.
Finally, fix the following linter warning:
> error-strings: error strings should not be capitalized or end with punctuation or a newline (revive)
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Apparently, not all files listed in /sys/kernel/cgroup/delegate must
exist in every cgroup, so we should ignore ENOENT.
Dot not ignore ENOENT on the directory itself though.
Change cgroupFilesToChown to not return ".", and refactor it to not do
any dynamic slice appending in case we're using the default built-in
list of files.
Fixes: 35d20c4e0
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Since commit 12e99a0f8d we do require Go >= 1.16, so this file
is no longer needed.
Also, this actually ensures that go >= 1.16 is used (otherwise
libcontainer/cgroups/getallpids.go won't compile).
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
It never returns any error, so let's drop it (in case it needs to be
re-added, it is easy to do so).
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Delegating cgroups to the container enables more complex workloads,
including systemd-based workloads. The OCI runtime-spec was
recently updated to explicitly admit such delegation, through
specification of cgroup ownership semantics:
https://github.com/opencontainers/runtime-spec/pull/1123
Pursuant to the updated OCI runtime-spec, change the ownership of
the container's cgroup directory and particular files therein, when
using cgroups v2 and when the cgroupfs is to be mounted read/write.
As a result of this change, systemd workloads can run in isolated
user namespaces on OpenShift when the sandbox's cgroupfs is mounted
read/write.
It might be possible to implement this feature in other cgroup
managers, but that work is deferred.
Signed-off-by: Fraser Tweedale <ftweedal@redhat.com>
Move test case comments to doc strings, and use t.Run.
Suggested-by: Sebastiaan van Stijn <github@gone.nl>
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
1. Instead of distinguishing between errors and warnings, let's treat all
errors as warnings, thus simplifying the code. This changes the
function behaviour for input like hugepages-BadNumberKb --
previously, the error from Atoi("BadNumber") was considered fatal,
now it's just another warnings.
2. Move the warning logging to HugePageSizes, thus simplifying the test
case, which no longer needs to read what logrus writes. Note that we
do not want to log all the warnings (as chances are very low we'll
get any, and if we do this means the code need to be updated), only
the first one.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
I have noticed that libct/cg/fs allocates 8K during init on every runc
execution:
> init github.com/opencontainers/runc/libcontainer/cgroups/fs @1.5 ms, 0.028 ms clock, 8512 bytes, 13 allocs
Apparently this is caused by global HugePageSizes variable init, which
is only used from GetStats (i.e. it is never used by runc itself).
Remove it, and use HugePageSizes() directly instead. Make it init-once,
so that GetStats (which, I guess, is periodically called by kubernetes)
does not re-read huge page sizes over and over.
This also removes 12 allocs and 8K from libct/cg/fs init section:
> $ time GODEBUG=inittrace=1 ./runc --help 2>&1 | grep cgroups/fs
> init github.com/opencontainers/runc/libcontainer/cgroups/fs @1.5 ms, 0.003 ms clock, 16 bytes, 1 allocs
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
1. Since GetHugePageSize do not have any external users (checked by
sourcegraph), and no internal user ever uses its second return value
(the error), let's drop it.
2. Rename GetHugePageSize -> HugePageSizes (drop the Get prefix as per
Go guidelines, add suffix since we return many sizes).
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
In case hugetlb is not supported, GetStats() should not error out,
and yet it does.
Assume that if GetHugePageSize return an error, hugetlb is
not supported (this is what cgroup v1 manager do).
Fixes: 89a87adb
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Users would like to have the possibility to skip checks for their
tests the same way they are skipped within the tests in runc.
Not exposing this variable makes it very hard to test components
that use this library. To avoid copying-and-pasting the code
into outside projects this variable sould be exposed to the users.
Signed-off-by: Itamar Holder <iholder@redhat.com>
Currently, we can create subcgroup in a rootless container with systemd cgroupv2 on centos8.
But after the container exited, the container cgroup and its subcgroup will not be removed.
Fix this by removing all directories recursively.
Fixes: https://github.com/opencontainers/runc/issues/3225
Signed-off-by: Kang Chen <kongchen28@gmail.com>
Currently the parent process of the container is moved to the right
cgroup v2 tree when systemd is using a hybrid model (last line with 0::):
$ runc --systemd-cgroup run myid
/ # cat /proc/self/cgroup
12:cpuset:/system.slice/runc-myid.scope
11:blkio:/system.slice/runc-myid.scope
10:devices:/system.slice/runc-myid.scope
9:hugetlb:/system.slice/runc-myid.scope
8:memory:/system.slice/runc-myid.scope
7:rdma:/
6:perf_event:/system.slice/runc-myid.scope
5:net_cls,net_prio:/system.slice/runc-myid.scope
4:freezer:/system.slice/runc-myid.scope
3:pids:/system.slice/runc-myid.scope
2:cpu,cpuacct:/system.slice/runc-myid.scope
1:name=systemd:/system.slice/runc-myid.scope
0::/system.slice/runc-myid.scope
However, if a second process is executed in the same container, it is
not moved to the right cgroup v2 tree:
$ runc exec myid /bin/sh -c 'cat /proc/self/cgroup'
12:cpuset:/system.slice/runc-myid.scope
11:blkio:/system.slice/runc-myid.scope
10:devices:/system.slice/runc-myid.scope
9:hugetlb:/system.slice/runc-myid.scope
8:memory:/system.slice/runc-myid.scope
7:rdma:/
6:perf_event:/system.slice/runc-myid.scope
5:net_cls,net_prio:/system.slice/runc-myid.scope
4:freezer:/system.slice/runc-myid.scope
3:pids:/system.slice/runc-myid.scope
2:cpu,cpuacct:/system.slice/runc-myid.scope
1:name=systemd:/system.slice/runc-myid.scope
0::/user.slice/user-1000.slice/session-8.scope
This commit makes that processes executed with exec are placed into the
right cgroup v2 tree. The implementation checks if systemd is using a
hybrid mode (by checking if cgroups v2 is mounted in
/sys/fs/cgroup/unified), if yes, the path of the cgroup v2 slice for
this container is saved into the cgroup path list.
The fs group driver has a similar issue, in this case none of the runc
run or runc exec commands put the process in the right cgroups v2. This
commit also fixes that.
Having the processes of the container in its own cgroup v2 is useful
for any BPF programs that rely on bpf_get_current_cgroup_id(), like
https://github.com/kinvolk/inspektor-gadget/ for instance.
[@kolyshkin: rebased]
Signed-off-by: Mauricio Vásquez <mauricio@kinvolk.io>
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
No need to add a file name to the error messages, as errors from
OpenFile and (*os.File).Write both contain the file name already.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
It is assumed that m.config is not nil, so these checks are redundant
(in case it is nil, NewManager panics and this code is unreachable).
Note that cgroups/manager.New checks that config is not nil.
Remove them.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Cgroup controllers should never panic, and yet sometimes they do.
Add a unit test to check that controllers never panic when called with
nil arguments and/or resources, and fix a few found cases.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
cgName and cgParent are only used when cgPath is empty, so move
their cleaning to the body of the appropriate "if" statement.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This way we
- won't re-initialize the paths if they were provided;
- will always have paths ready for every method.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
wineway