Before this patch, setFreezer does
- open/read/close (to check if the freezer is supported)
- open/write/close (to set the value)
- open/read/close (to check the value)
Three opens is a bit excessive. Refactor to only open the file once:
- open (to check if the freezer is supported)
- write (to set the value)
- seek/read (to check the value)
- close
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
In case configs.Undefined or any wrong value is passed, there is no need
to check whether the freezer is supported.
Move arguments check to the beginning to avoid an unnecessary call to
supportFreezer().
While at it, simplify the "whether to return an error if freezer is not
supported" check.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
A cgroup manager's Set method sets cgroup resources, but historically
it was accepting configs.Cgroups.
Refactor it to accept resources only. This is an improvement from the
API point of view, as the method can not change cgroup configuration
(such as path to the cgroup etc), it can only set (modify) its
resources/limits.
This also lays the foundation for complicated resource updates, as now
Set has two sets of resources -- the one that was previously specified
during cgroup manager creation (or the previous Set), and the one passed
in the argument, so it could deduce the difference between these. This
is a long term goal though.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Commit 5d0ffbf9c8 added OOM kill count checking and better container
start/run/exec error reporting in case we hit OOM.
It also introduced warnings like these:
> level=warning msg="unable to get oom kill count" error="openat2
> /sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/test_hello/memory.events:
> no such file or directory"
In case of rootless containers, unless cgroup is delegated or systemd is
used, runc can not create a cgroup and thus it fails to get OOM kill
count. This is expected, and the warning should not be shown in this
case.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
For fs, commit fc620fdf81 made rootless field private,
and for fs2, it was always private, and yet comments in both
mention it as m.Rootless.
Fix it.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Moving these utilities to a separate package, so that consumers of this
package don't have to pull in the whole "system" package.
Looking at uses of these utilities (outside of runc itself);
`RunningInUserNS()` is used by [various external consumers][1],
so adding a "Deprecated" alias for this.
[1]: https://grep.app/search?current=2&q=.RunningInUserNS
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Some controllers might still have stats available even if they are
disabled (this is definitely so for cpu.stat -- see earlier commit).
Some stat methods might implement sensible fallbacks (see previous
commit for statPids.
In the view of all that, it makes sense to not check if a particular
controller is available, but rather ignore ENOENT from it.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
When getting pids stats, instead of checking whether the pids controller
is available, let's use a fall back function in case pids.current does
not exist. This simplifies the logic in fs2.GetStats.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
It is inefficient to create an associative map for the whole purpose of
counting the number of elements in it, especially if the elements are
all unique. It uses more CPU than necessary and creates some work for
the garbage collector.
The file we read contains PIDs and newlines, and the easiest/fastest way
to get the number of PIDs is just to count the newlines.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Giuseppe found out that cpu.stat for a cgroup is available even if
the cpu controller is not enabled for it. So, let's call statCpu
regradress, and ignore ENOENT.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
There is no memory.{current,max} for the root node in cgroup v2, and
thus stats for "/sys/fs/cgroup" return an error.
The same thing works with cgroup v1 (as there are
memory.{usage,limit}_in_bytes files in the root node).
Emulate stats for /sys/fs/cgroup by getting numbers from
/proc/self/meminfo.
NOTE that both memory.current (in cgroup v2) and memory.usage_in_bytes
(in cgroup v1) include page cache etc into the number, so we do the same
when calculating memory usage (as opposed to number reported by "free",
which excludes page cache and buffers).
[v2: check for cgroup files first, as future kernels might add it]
[v3: don't subtract cache from mem_used, simplifying the logic]
[Initially, I wanted to avoid parsing yet another /proc file and
instead mock some numbers using data from memory.stat but was
unable to come up with formulae that make sense.]
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Existing code ignores ENOENT error in case we're reading data from
controls that might not be enabled. While this is correct, the code
can be improved:
1. Check name != "" instead of moduleName != "memory", as these checks
are equivalent but the new one is faster.
2. It does not make sense to ignore subsequent errors -- if the control
is not available, we won't hit this codepath.
3. Add a comment explaining why we ignore the error.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
cgroup v1 reports combined mem+swap in stats.MemoryStats.SwapUsage.
In cgroup v2, swap is separate.
For the sake of compatibility, make v2 report mem+swap as well.
This also includes Limit.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
if bfq is not loaded, then io.bfq.weight is not available. io.weight
should always be available and is the next best equivalent thing.
Signed-off-by: Daniel Dao <dqminh89@gmail.com>
bfq weight controller (i.e. io.bfq.weight if present) is still using the
same bfq weight scheme (i.e 1->1000, see [1].) Unfortunately the
documentation for this was wrong, and only fixed recently [2].
Therefore, if we map blkio weight to io.bfq.weight, there's no need to
do any conversion. Otherwise, we will try to write invalid value which
results in error such as:
```
time="2021-02-03T14:55:30Z" level=error msg="container_linux.go:367: starting container process caused: process_linux.go:495: container init caused: process_linux.go:458: setting cgroup config for procHooks process caused: failed to write \"7475\": write /sys/fs/cgroup/runc-cgroups-integration-test/test-cgroup/io.bfq.weight: numerical result out of range"
```
[1] https://github.com/torvalds/linux/blob/master/Documentation/block/bfq-iosched.rst
[2] https://github.com/torvalds/linux/commit/65752aef0a407e1ef17ec78a7fc31ba4e0b360f9
Signed-off-by: Daniel Dao <dqminh89@gmail.com>
In some cases, container init fails to start because it is killed by
the kernel OOM killer. The errors returned by runc in such cases are
semi-random and rather cryptic. Below are a few examples.
On cgroup v1 + systemd cgroup driver:
> process_linux.go:348: copying bootstrap data to pipe caused: write init-p: broken pipe
> process_linux.go:352: getting the final child's pid from pipe caused: EOF
On cgroup v2:
> process_linux.go:495: container init caused: read init-p: connection reset by peer
> process_linux.go:484: writing syncT 'resume' caused: write init-p: broken pipe
This commits adds the OOM method to cgroup managers, which tells whether
the container was OOM-killed. In case that has happened, the original error
is discarded (unless --debug is set), and the new OOM error is reported
instead:
> ERRO[0000] container_linux.go:367: starting container process caused: container init was OOM-killed (memory limit too low?)
Also, fix the rootless test cases that are failing because they expect
an error in the first line, and we have an additional warning now:
> unable to get oom kill count" error="no directory specified for memory.oom_control
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This makes the code simpler and more future-proof, in case
any more values will appear in hugetlb.*.events.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
1. This is the only function in the package with Get prefix
that does not read a file (but parses a string). Rename
accordingly, and convert the callers.
GetCgroupParamKeyValue -> ParseKeyValue
2. Use strings.Split rather than strings.Fields. Split by a space
is 2x faster, plus we can limit the splitting. The downside is
we have to strip a newline in one of the callers.
3. Improve the doc and the code flow.
4. Fix a test case with invalid data (spaces at BOL).
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
In the past we incorrectly handled eBPF errors in two ways:
1. We would only ignore errors if there was an allow rule in the list
(this doesn't make sense because for security purposes we only care
if a *deny* rule is being ignored). Arguably this is a security flaw
but you would only get an error from bpf(2) in rare cases, and thus
is not a big enough deal to go through security review.
2. If we were in a rootless container we would still return an error
even though bpf(2) is blocked for rootless containers.
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Move the Device-related types to libcontainer/devices, so that
the package can be used in isolation. Aliases have been created
in libcontainer/configs for backward compatibility.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
errors.Wrap(err, "some error") returns nil if err is nil, so it's
slightly clearer to just return early than to set the error to nil
and call errors.Wrap(). This is also somewhat defensive in case
we decide to replace `errors.Wrap()` for golang's native `%w`
wrapping.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
1. Don't wrap the error from fscommon.GetCgroupParamUint as it already
contains the file name.
2. Don't put file name when wrapping the error from ioutil.ReadFile
since it already has it.
3. Don't reconstruct file name, use existing one since it's available.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
The kubelet uses libct/cgroups code to set up cgroups. It creates a
parent cgroup (kubepods) to put the containers into.
The problem (for cgroupv2 that uses eBPF for device configuration) is
the hard requirement to have devices cgroup configured results in
leaking an eBPF program upon every kubelet restart. program. If kubelet
is restarted 64+ times, the cgroup can't be configured anymore.
Work around this by adding a SkipDevices flag to Resources.
A check was added so that if SkipDevices is set, such a "container"
can't be started (to make sure it is only used for non-containers).
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This (and the converting function) is only used by one of the four
cgroup drivers. The other three do some checking and conversion in
place, so let the fs2 do the same.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
When we use cgroup with systemd driver, the cgroup path will be auto removed
by systemd when all processes exited. So we should check cgroup path exists
when we access the cgroup path, for example in `kill/ps`, or else we will
got an error.
Signed-off-by: lifubang <lifubang@acmcoder.com>
1. In cases there are no sub-cgroups, a single rmdir should be faster
than iterating through the list of files.
2. Use unix.Rmdir() to save one more syscall since os.Remove() tries
unlink(2) first which fails on a directory, and only then tries
rmdir(2).
3. Re-use rmdir.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
1. Partially revert "CreateCgroupPath: only enable needed controllers"
If we update a resource which did not limited in the beginning,
it will have no effective.
2. Returns err if we use an non enabled controller,
or else the user may feel success, but actually there are no effective.
Signed-off-by: lifubang <lifubang@acmcoder.com>
Kir Kolyshkin