Bug #17244
open
Make sure cgroupsV2 works with Arvados
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Description
Reading
https://docs.docker.com/config/containers/runmetrics/
Running Docker on cgroup v2
Docker supports cgroup v2 experimentally since Docker 20.10. Running Docker on cgroup v2 also requires the following conditions to be satisfied:
containerd: v1.4 or later
runc: v1.0.0-rc91 or later
Kernel: v4.15 or later (v5.2 or later is recommended)Note that the cgroup v2 mode behaves slightly different from the cgroup v1 mode:
The default cgroup driver (dockerd --exec-opt native.cgroupdriver) is “systemd” on v2, “cgroupfs” on v1.
The default cgroup namespace mode (docker run --cgroupns) is “private” on v2, “host” on v1.
The docker run flags --oom-kill-disable and --kernel-memory are discarded on v2.
With all this changes, we have to make sure that:
- We can run a distro that has cgroup v2 by default (As in Fedora 2020) or kernel parameters that boot up with cgroups v2 enabled in systemd (kernel param systemd.unified_cgroup_hierarchy=1) and docker version >= 2020.04
- We can guide the admin to upgrade to cgroup v2 and have a test case easy to check that arvados will run
The last point is important because the current error is kindof cryptic:
applying cgroup configuration for process caused: cannot enter cgroupv2 "/sys/fs/cgroup/docker" with domain controllers
There also cryptic messages with a cgroupsv2 enabled host and Docker 19.03.13
Status: Downloaded newer image for hello-world:latest docker: Error response from daemon: cgroups: cgroup mountpoint does not exist: unknown. ERRO[0005] error waiting for container: context canceled
https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html
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