ZFS on Hetzner Rescue fails with `checking whether inode_owner_or_capable() takes user_ns... configure: error:`

ru flag

Normally, when booting into the Hetzner rescue system, using the 'zfs' command will automatically install zfs tooling inside the rescue system. This is currently not working;

checking whether inode_owner_or_capable() takes user_ns... configure: error: 
        *** None of the expected "capability" interfaces were detected.
        *** This may be because your kernel version is newer than what is
        *** supported, or you are using a patched custom kernel with
        *** incompatible modifications.
        *** ZFS Version: zfs-2.1.11-1
        *** Compatible Kernels: 3.10 - 6.2

Install failed, please fix manually!
bash: line 499: zfs: command not found
ru flag

The problem is that the rescue kernel has been updated to 6.3, which is not yet supported by the latest zfs-on-linux release. This is slightly concerning.

The solution is to:

  • select Linux (old) in the 'Operating system' selection box in the Hetzner robot interface 'Rescue' tab.
  • Download the zfs download script, since it's not installed in the old rescue system:

(Please note that I added --no-check-certificate to the wget command, as this old version of wget does not download the zfs release otherwise. Unlikely, but this does make you vulnerable to mitm attacks)

  • run it:
bash ./zfs

After this, the zfs tooling can be used as before.

pzkpfw avatar
cn flag
"The Hetzner Rescue System is a Debian based Linux live environment" -- as far as I know Debian does not ship zfs by default, and Hetzner does not offer zfs as an option when deploying an instance or a volume, so I'm not sure why you're surprised.

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