CoreOS beta (835.4.0)
rkt version 0.9.0
appc version 0.7.1

Running cAdvisor like this:

rkt run \
--net=host \
--volume volume-rootfs,kind=host,source=/,readOnly=true \
--volume volume-var-run,kind=host,source=/var/run,readOnly=false \
--volume volume-sys,kind=host,source=/sys,readOnly=true \
--volume volume-var-lib-docker,kind=host,source=/var/lib/docker,readOnly=true \
quay.io/scaleft/cadvisor-volumes:latest -- --logtostderr

This is just a port of the docker run command that cAdvisor has in their README which runs successfully, and works on the same versions:

sudo docker run \
  --volume=/:/rootfs:ro \
  --volume=/var/run:/var/run:rw \
  --volume=/sys:/sys:ro \
  --volume=/var/lib/docker/:/var/lib/docker:ro \
  --publish=8080:8080 \
  --detach=true \
  --name=cadvisor \
  google/cadvisor:latest

This is the upstream cadvisor, but with VOLUME lines added to the dockerfile (yes, in newer rkt we could directly add --mount commands, but not in this version):
https://github.com/pquerna/cadvisor-volumes/blob/master/Dockerfile

This above fails with with:

[  307.854712] cadvisor[4]: I1117 00:23:10.022660 00004 container.go:430] Failed to update stats for container "/": open /sys/fs/cgroup/memory/system.slice/system-sshd.slice/sshd@0-10.0.127.167:22-10.0.225.44:48599.service/system.slice/cadvisor-volumes.service/cgroup.procs/memory.stat: not a directory, continuing to push stats
[  307.861986] cadvisor[4]: F1117 00:23:10.029937 00004 cadvisor.go:88] Failed to start container manager: readdirent: not a directory

full logs: https://gist.github.com/pquerna/c190b1b59e209510f0f7

cAdvisor is trying to open /sys/fs/cgroup/memory/system.slice/system-sshd.slice/sshd@0-10.0.127.167:22-10.0.225.44:48599.service/system.slice/cadvisor-volumes.service/cgroup.procs/memory.stat, which is not a file. The path /sys/fs/cgroup/memory/system.slice/system-sshd.slice/sshd@0-10.0.127.167:22-10.0.225.44:48599.service/system.slice/cadvisor-volumes.service does exist, but cgroup.procs is an empty file, not a directory.