Comment 4 for bug 1871176

Also experienced on an lxd vm when lvm2 is uninstalled and subsequently reinstalled.

root@cloudinit-0721-232304wnvzml11:~# apt install lvm2
Reading package lists... Done
Building dependency tree
Reading state information... Done
lvm2 is already the newest version (2.03.07-1ubuntu1).
0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.
1 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] y
Setting up lvm2 (2.03.07-1ubuntu1) ...
update-initramfs: deferring update (trigger activated)
Failed to restart lvm2-lvmpolld.service: Unit lvm2-lvmpolld.socket is masked.
invoke-rc.d: initscript lvm2-lvmpolld, action "restart" failed.
● lvm2-lvmpolld.service - LVM2 poll daemon
     Loaded: loaded (/lib/systemd/system/lvm2-lvmpolld.service; static; vendor p
reset: enabled)
     Active: inactive (dead)
       Docs: man:lvmpolld(8)
dpkg: error processing package lvm2 (--configure):
 installed lvm2 package post-installation script subprocess returned error exit
status 1
Processing triggers for initramfs-tools (0.136ubuntu6.7) ...
update-initramfs: Generating /boot/initrd.img-5.4.0-1071-kvm
W: mkconf: MD subsystem is not loaded, thus I cannot scan for arrays.
W: mdadm: failed to auto-generate temporary mdadm.conf file.
Errors were encountered while processing:
 lvm2
E: Sub-process /usr/bin/dpkg returned an error code (1)
root@cloudinit-0721-232304wnvzml11:~# echo $?
100