In a focal container, after the deb upgrade from to 2.48+20.04 (from 2.45.1+20.04.2), `snap try` no longer works.
The same tree works fine with `snap try` outside of the container
Downgrading the deb to the previous version fixed the issue
journalct output shows:
Dec 16 16:02:20 maas sudo[2191]: ack : TTY=pts/1 ; PWD=/home/ack/canonical/src/maas ; USER=root ; COMMAND=/usr/bin/snap try build/dev-snap/prime/
Dec 16 16:02:20 maas sudo[2191]: pam_unix(sudo:session): session opened for user root by ack(uid=0)
Dec 16 16:02:21 maas systemd[1]: Reloading.
Dec 16 16:02:21 maas systemd[1]: /lib/systemd/system/dbus.socket:5: ListenStream= references a path below legacy directory /var/run/, updating /var/run/dbus/system_bus_socket → /run/dbus/system_bus_socket; please update the unit file accordingly.
Dec 16 16:02:21 maas systemd[1]: systemd-udevd.service: Attaching egress BPF program to cgroup /sys/fs/cgroup/unified/system.slice/systemd-udevd.service failed: Invalid argument
Dec 16 16:02:21 maas systemd[1]: systemd-machined.service: Attaching egress BPF program to cgroup /sys/fs/cgroup/unified/system.slice/systemd-machined.service failed: Invalid argument
Dec 16 16:02:21 maas systemd[1]: systemd-logind.service: Attaching egress BPF program to cgroup /sys/fs/cgroup/unified/system.slice/systemd-logind.service failed: Invalid argument
Dec 16 16:02:21 maas systemd[1]: systemd-journald.service: Attaching egress BPF program to cgroup /sys/fs/cgroup/unified/system.slice/systemd-journald.service failed: Invalid argument
Dec 16 16:02:21 maas systemd[1]: Reloading.
Dec 16 16:02:22 maas systemd[1]: /lib/systemd/system/dbus.socket:5: ListenStream= references a path below legacy directory /var/run/, updating /var/run/dbus/system_bus_socket → /run/dbus/system_bus_socket; please update the unit file accordingly.
Dec 16 16:02:22 maas systemd[1]: systemd-udevd.service: Attaching egress BPF program to cgroup /sys/fs/cgroup/unified/system.slice/systemd-udevd.service failed: Invalid argument
Dec 16 16:02:22 maas systemd[1]: systemd-machined.service: Attaching egress BPF program to cgroup /sys/fs/cgroup/unified/system.slice/systemd-machined.service failed: Invalid argument
Dec 16 16:02:22 maas systemd[1]: systemd-logind.service: Attaching egress BPF program to cgroup /sys/fs/cgroup/unified/system.slice/systemd-logind.service failed: Invalid argument
Dec 16 16:02:22 maas systemd[1]: systemd-journald.service: Attaching egress BPF program to cgroup /sys/fs/cgroup/unified/system.slice/systemd-journald.service failed: Invalid argument
Dec 16 16:02:22 maas systemd[1]: Mounting Mount unit for maas, revision x2...
-- Subject: A start job for unit snap-maas-x2.mount has begun execution
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- A start job for unit snap-maas-x2.mount has begun execution.
--
-- The job identifier is 691.
Dec 16 16:02:22 maas mount[2289]: This doesn't look like a squashfs image.
Dec 16 16:02:22 maas systemd[1]: snap-maas-x2.mount: Mount process exited, code=exited, status=255/EXCEPTION
-- Subject: Unit process exited
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- An n/a= process belonging to unit snap-maas-x2.mount has exited.
--
-- The process' exit code is 'exited' and its exit status is 255.
Dec 16 16:02:22 maas systemd[1]: snap-maas-x2.mount: Failed with result 'exit-code'.
-- Subject: Unit failed
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- The unit snap-maas-x2.mount has entered the 'failed' state with result 'exit-code'.
Dec 16 16:02:22 maas systemd[1]: Failed to mount Mount unit for maas, revision x2.
-- Subject: A start job for unit snap-maas-x2.mount has failed
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- A start job for unit snap-maas-x2.mount has finished with a failure.
--
-- The job identifier is 691 and the job result is failed.
Dec 16 16:02:22 maas systemd[1]: snapd.service: Got notification message from PID 2286, but reception only permitted for main PID 315
Dec 16 16:02:22 maas systemd[1]: Reloading.
Dec 16 16:02:22 maas systemd[1]: /lib/systemd/system/dbus.socket:5: ListenStream= references a path below legacy directory /var/run/, updating /var/run/dbus/system_bus_socket → /run/dbus/system_bus_socket; please update the unit file accordingly.
Dec 16 16:02:22 maas systemd[1]: systemd-udevd.service: Attaching egress BPF program to cgroup /sys/fs/cgroup/unified/system.slice/systemd-udevd.service failed: Invalid argument
Dec 16 16:02:22 maas systemd[1]: systemd-machined.service: Attaching egress BPF program to cgroup /sys/fs/cgroup/unified/system.slice/systemd-machined.service failed: Invalid argument
Dec 16 16:02:22 maas systemd[1]: systemd-logind.service: Attaching egress BPF program to cgroup /sys/fs/cgroup/unified/system.slice/systemd-logind.service failed: Invalid argument
Dec 16 16:02:22 maas systemd[1]: systemd-journald.service: Attaching egress BPF program to cgroup /sys/fs/cgroup/unified/system.slice/systemd-journald.service failed: Invalid argument
Dec 16 16:02:22 maas systemd[1]: Reloading.
Dec 16 16:02:22 maas systemd[1]: /lib/systemd/system/dbus.socket:5: ListenStream= references a path below legacy directory /var/run/, updating /var/run/dbus/system_bus_socket → /run/dbus/system_bus_socket; please update the unit file accordingly.
Dec 16 16:02:22 maas systemd[1]: systemd-udevd.service: Attaching egress BPF program to cgroup /sys/fs/cgroup/unified/system.slice/systemd-udevd.service failed: Invalid argument
Dec 16 16:02:22 maas systemd[1]: systemd-machined.service: Attaching egress BPF program to cgroup /sys/fs/cgroup/unified/system.slice/systemd-machined.service failed: Invalid argument
Dec 16 16:02:22 maas systemd[1]: systemd-logind.service: Attaching egress BPF program to cgroup /sys/fs/cgroup/unified/system.slice/systemd-logind.service failed: Invalid argument
Dec 16 16:02:22 maas systemd[1]: systemd-journald.service: Attaching egress BPF program to cgroup /sys/fs/cgroup/unified/system.slice/systemd-journald.service failed: Invalid argument
Dec 16 16:02:22 maas snapd[315]: taskrunner.go:271: [change 1244 "Mount snap \"maas\" (unset)" task] failed: [start snap-maas-x2.mount] failed with exit status 1: Job failed. See "journalctl -xe" for details.
Dec 16 16:02:22 maas snapd[315]: handlers.go:496: Reported install problem for "maas" as already-reported
Dec 16 16:02:22 maas sudo[2191]: pam_unix(sudo:session): session closed for user root
My theory but we need to add tests to prove it and debug this properly is that the issue relates to the change we made to the snapd-generator to make preseeded images work inside containers. I think we are emitting squashfs options even for dir bind mounts, and that I suppose would confuse/break things.