Looks like I’ll probably have to abandon my adventures with Docker on the r-pi.
Any attempt to to RUN command (say, apt-get update) in the Dockerfile, I get the following error:
The command '/bin/sh -c 'apt-get update'' returned a non-zero code: 139
This equates to a segmenatation fault, although the command runs fine from a standard shell.
I tried running the docker daemon in debug mode but nothing untoward is reported.
But a quick glance at /var/log/daemon.log shows the following:
systemd: Failed to set cpu.cfs_period_us on /system.slice/var-lib-docker-overlay-...-merged.mount: Permission denied systemd: Failed to set cpu.cfs_quota_us on /system.slice/var-lib-docker-overlay-...-merged.mount: Permission denied
At friends at Google then point us at https://github.com/opencontainers/runc/issues/57 and pretty much everything checks out except for
/sys/fs/cgroup/cpu/cpu.cfs_quota_us. Any potential issue for Debian/Jessie should have been fixed a while back.
Oddly, everything including and under /sys/fs/cgroup has a timestamp of 1 Jan 1970 suggesting that something’s not quite right.
This is now happening on two different SD cards on different r-pi’s with different versions of Hypriot; it’s not a Docker issue. Attempting to apply the latest updates gives further breakage. Time to say goodbye and head back to x86.