package multipath-tools 0.8.5-1ubuntu6 failed to install/upgrade: installed multipath-tools package post-installation script subprocess returned error exit status 1

[Nelson Pavlosky]

I'm using Linode and have a server set up with Ubuntu 20.10. I ssh-ed in and got a message telling me to upgrade Ubuntu, ok, so I did and at some point during the process an error occurred and asked if I wanted to "Send the problem to the developers" so I said yes and it gave me a link and I had to make an account with Ubuntu then it told me I needed to fill in this textarea, so that's what I'm doing.

ProblemType: Package
DistroRelease: Ubuntu 21.04
Package: multipath-tools 0.8.5-1ubuntu6
Uname: Linux 5.11.13-x86_64-linode143 x86_64
ApportVersion: 2.20.11-0ubuntu65
Architecture: amd64
CasperMD5CheckResult: pass
Date: Thu May 13 14:34:19 2021
ErrorMessage: installed multipath-tools package post-installation script subprocess returned error exit status 1
InstallationDate: Installed on 2020-10-22 (203 days ago)
InstallationMedia: Ubuntu-Server 20.10 "Groovy Gorilla" - Release amd64 (20201021)
Python3Details: /usr/bin/python3.9, Python 3.9.4, python3-minimal, 3.9.4-1
PythonDetails: N/A
RelatedPackageVersions:
 dpkg 1.20.9ubuntu1
 apt 2.2.3
SourcePackage: multipath-tools
Title: package multipath-tools 0.8.5-1ubuntu6 failed to install/upgrade: installed multipath-tools package post-installation script subprocess returned error exit status 1
UpgradeStatus: Upgraded to hirsute on 2021-05-13 (0 days ago)

[Christian Ehrhardt  (paelzer)]

Hi Nelson,
this is a deficiency in your installation.

The Multipath-tools package expects dm-multipath to exist and be a loadable module.

And we see it fail loading - in your logs:
May 13 14:34:19 banana multipathd[70987]: --------start up--------
May 13 14:34:19 banana multipathd[70987]: read /etc/multipath.conf
May 13 14:34:19 banana multipathd[70987]: DM multipath kernel driver not loaded
May 13 14:34:19 banana multipathd[70987]: failed to increase buffer size
May 13 14:34:19 banana multipathd[70987]: path checkers start up
May 13 14:34:19 banana multipathd[70987]: DM multipath kernel driver not loaded
May 13 14:34:19 banana systemd[1]: multipathd.service: Main process exited, code=exited, status=1/FAILURE

But also in your log we see:
May 13 14:34:19 banana modprobe[70986]: modprobe: WARNING: Module dm-multipath not found in directory /lib/modules/5.11.13-x86_64-linode143

That is the underlying reasons and the problem here is that your kernel is the linode kernel that isn't providing this.
https://www.linode.com/docs/guides/how-to-change-your-linodes-kernel/

If you'd switch to a default ubuntu kernel like "linux-generic" that will provide the module, and then allow multipath to run.

[Launchpad Janitor (janitor)]

[Expired for multipath-tools (Ubuntu) because there has been no activity for 60 days.]