zfs-mount.service and others fail inside unpriv containers

[Ryan Harper]

1)
# lsb_release -rd
Description: Ubuntu Focal Fossa (development branch)
Release: 20.04

2)
# apt-cache policy zfsutils-linux
zfsutils-linux:
  Installed: (none)
  Candidate: 0.8.3-1ubuntu3
  Version table:
     0.8.3-1ubuntu3 500
        500 http://archive.ubuntu.com/ubuntu focal/main amd64 Packages

3) apt install zfsutils-linux installs successfully
4) apt install zfsutils-linux; echo $? == 0
installs but apt returns error code due to zfs services failing to start successfully

See "systemctl status zfs-mount.service" and "journalctl -xe" for details.
invoke-rc.d: initscript zfs-mount, action "start" failed.
● zfs-mount.service - Mount ZFS filesystems
     Loaded: loaded (]8;;file://f2/lib/systemd/system/zfs-mount.service/lib/systemd/system/zfs-mount.service]8;;; enabled; vendor preset: enabled)
     Active: failed (Result: exit-code) since Mon 2020-02-10 16:18:04 UTC; 23ms ago
       Docs: ]8;;man:zfs(8)man:zfs(8)]8;;
    Process: 1672 ExecStart=/sbin/zfs mount -a (code=exited, status=1/FAILURE)
   Main PID: 1672 (code=exited, status=1/FAILURE)

Feb 10 16:18:04 f2 systemd[1]: Starting Mount ZFS filesystems...
Feb 10 16:18:04 f2 zfs[1672]: /dev/zfs and /proc/self/mounts are required.
Feb 10 16:18:04 f2 zfs[1672]: Try running 'udevadm trigger' and 'mount -t proc proc /proc' as root.
Feb 10 16:18:04 f2 systemd[1]: zfs-mount.service: Main process exited, code=exited, status=1/FAILURE
Feb 10 16:18:04 f2 systemd[1]: zfs-mount.service: Failed with result 'exit-code'.
Feb 10 16:18:04 f2 systemd[1]: Failed to start Mount ZFS filesystems.

I'm inside a LXD unpriv container. By default, there are no permissions to mount proc, modprobe modules, etc.

E: Sub-process /usr/bin/dpkg returned an error code (1)
100

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: zfsutils-linux 0.8.3-1ubuntu3
ProcVersionSignature: Ubuntu 5.4.0-9.12-generic 5.4.3
Uname: Linux 5.4.0-9-generic x86_64
ApportVersion: 2.20.11-0ubuntu16
Architecture: amd64
Date: Mon Feb 10 15:50:42 2020
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=C.UTF-8
SourcePackage: zfs-linux
UpgradeStatus: No upgrade log present (probably fresh install)

[Ryan Harper (raharper)]

Note, the fact that these services fail isn't new; they've failed for a long time. However, reporting the service failure to apt is new. For example of bionic, we don't see an apt error:

# lsb_release -rd
Description: Ubuntu 18.04.4 LTS
Release: 18.04

# apt-cache policy zfsutils-linux
zfsutils-linux:
  Installed: 0.7.5-1ubuntu16.7
  Candidate: 0.7.5-1ubuntu16.7
  Version table:
 *** 0.7.5-1ubuntu16.7 500
        500 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     0.7.5-1ubuntu15 500
        500 http://archive.ubuntu.com/ubuntu bionic/main amd64 Packages

# apt install zfsutils-linux
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following package was automatically installed and is no longer required:
  libfreetype6
Use 'apt autoremove' to remove it.
The following additional packages will be installed:
  libnvpair1linux libuutil1linux libzfs2linux libzpool2linux zfs-zed
Suggested packages:
  zfs-modules | zfs-dkms nfs-kernel-server samba-common-bin zfs-initramfs | zfs-dracut
The following NEW packages will be installed:
  libnvpair1linux libuutil1linux libzfs2linux libzpool2linux zfs-zed zfsutils-linux
0 upgraded, 6 newly installed, 0 to remove and 0 not upgraded.
Need to get 1168 kB of archives.
After this operation, 4259 kB of additional disk space will be used.
Do you want to continue? [Y/n] y
Get:1 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 libnvpair1linux amd64 0.7.5-1ubuntu16.7 [45.4 kB]
Get:2 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 libuutil1linux amd64 0.7.5-1ubuntu16.7 [48.3 kB]
Get:3 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 libzpool2linux amd64 0.7.5-1ubuntu16.7 [547 kB]
Get:4 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 libzfs2linux amd64 0.7.5-1ubuntu16.7 [128 kB]
Get:5 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 zfsutils-linux amd64 0.7.5-1ubuntu16.7 [342 kB]
Get:6 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 zfs-zed amd64 0.7.5-1ubuntu16.7 [57.7 kB]
Fetched 1168 kB in 1s (1972 kB/s)
Selecting previously unselected package libnvpair1linux.
(Reading database ... 28654 files and directories currently installed.)
Preparing to unpack .../0-libnvpair1linux_0.7.5-1ubuntu16.7_amd64.deb ...
Unpacking libnvpair1linux (0.7.5-1ubuntu16.7) ...
Selecting previously unselected package libuutil1linux.
Preparing to unpack .../1-libuutil1linux_0.7.5-1ubuntu16.7_amd64.deb ...
Unpacking libuutil1linux (0.7.5-1ubuntu16.7) ...
Selecting previously unselected package libzpool2linux.
Preparing to unpack .../2-libzpool2linux_0.7.5-1ubuntu16.7_amd64.deb ...
Unpacking libzpool2linux (0.7.5-1ubuntu16.7) ...
Selecting previously unselected package libzfs2linux.
Preparing to unpack .../3-libzfs2linux_0.7.5-1ubuntu16.7_amd64.deb ...
Unpacking libzfs2linux (0.7.5-1ubuntu16.7) ...
Selecting previously unselected package zfsutils-linux.
Preparing to unpack .../4-zfsutils-linux_0.7.5-1ubuntu16.7_amd64.deb ...
Unpacking zfsutils-linux (0.7.5-1ubuntu16.7) ...
Selecting previously unselected package zfs-zed.
Preparing to unpack .../5-zfs-zed_0.7.5-1ubuntu16...

[Richard Laager (rlaager)]

What was the expected result? Are you expecting to be able to just install ZFS in a container (but not use it)? Or are you expecting it to actually work? The user space tools can’t do much of anything without talking to the kernel.

[Ryan Harper (raharper)]

The latter; This may only be a packaging issue in that bionic release of tools don't report an error up through apt, where in focal (and eoan) report an error to apt.

[Ryan Harper (raharper)]

Sorry, I do not expect the zfs tools to function inside the unpriv container. There is some packaging change between previous releases which did not report an error to apt/dpkg when installing.