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https://github.com/opencontainers/runc.git
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Mauricio Vásquez
a8435007d9
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>