Obtain statistics of CPU and memory usage from one cgroup

Question

Context

I have a system in which I have to check periodically usage:

• relative (percents) for CPU
• and absolute (GB) for memory.

How it's currently implemented

Language we're using is python.

system-wide psutil

For system-wide stats it's trivial since we can use psutil.cpu_percent() and psutil.virtual_memory().

cgroup (v1)

The problem is that sometimes the script is run inside container, and then we'd like to monitor usage of particular cgroup instead of system-wide statistics.

There's already implementation for cgroups in our system which bases on:

• for CPU:
  • cpu.cfs_period_us
  • cpu.cfs_quota_us
  • cpuacct.usage
• for memory:
  • memory.usage_in_bytes
  • memory.limit_in_bytes

What I need

Here I need an answer for two questions:

• Is the present implementation based on reading values directly from files ok for cgroup?
• If no, are there any tools which supports obtaining such kind of information easily.
• If yes, how can I adapt this solution to cgroup2?

Why current solution doesn't work for cgroup2

The main problem I have now is lack of support for cgroup2 since current implementation is based on nested files structure.

cgroup on Ubuntu 20.04

$ cat /proc/mounts | grep cgroup tmpfs /sys/fs/cgroup tmpfs ro,nosuid,nodev,noexec,mode=755 0 0 cgroup2 /sys/fs/cgroup/unified cgroup2 rw,nosuid,nodev,noexec,relatime,nsdelegate 0 0 cgroup /sys/fs/cgroup/systemd cgroup rw,nosuid,nodev,noexec,relatime,xattr,name=systemd 0 0 cgroup /sys/fs/cgroup/rdma cgroup rw,nosuid,nodev,noexec,relatime,rdma 0 0 cgroup /sys/fs/cgroup/cpuset cgroup rw,nosuid,nodev,noexec,relatime,cpuset 0 0 cgroup /sys/fs/cgroup/devices cgroup rw,nosuid,nodev,noexec,relatime,devices 0 0 cgroup /sys/fs/cgroup/perf_event cgroup rw,nosuid,nodev,noexec,relatime,perf_event 0 0 cgroup /sys/fs/cgroup/freezer cgroup rw,nosuid,nodev,noexec,relatime,freezer 0 0 cgroup /sys/fs/cgroup/pids cgroup rw,nosuid,nodev,noexec,relatime,pids 0 0 cgroup /sys/fs/cgroup/memory cgroup rw,nosuid,nodev,noexec,relatime,memory 0 0 cgroup /sys/fs/cgroup/net_cls,net_prio cgroup rw,nosuid,nodev,noexec,relatime,net_cls,net_prio 0 0 cgroup /sys/fs/cgroup/blkio cgroup rw,nosuid,nodev,noexec,relatime,blkio 0 0 cgroup /sys/fs/cgroup/cpu,cpuacct cgroup rw,nosuid,nodev,noexec,relatime,cpu,cpuacct 0 0 cgroup /sys/fs/cgroup/hugetlb cgroup rw,nosuid,nodev,noexec,relatime,hugetlb 0 0 

cgroup2 on Ubuntu 22.04

$ cat /proc/mounts | grep cgroup cgroup2 /sys/fs/cgroup cgroup2 rw,nosuid,nodev,noexec,relatime 0 0