Update proxmox

apt-get update; apt-get -y upgrade; apt-get -y dist-upgrade; # apt-get autoremove

Do patch on initramfs before reboot! Look at this article if you want boot on LVM after update!

Proxmox fail to boot. LVM

You do this:

apt-get update ; apt-get upgrade

after proxmox fail to boot!
It is ok. Proxmox is shit!

Use this magic shell command from root:

patch -p0 -d / <<EOF
--- /usr/share/initramfs-tools/scripts/local-top/lvm2 2009-08-17 21:28:09.000000000 +0400
+++ /usr/share/initramfs-tools/scripts/local-top/lvm2 2018-07-03 17:33:50.112702809 +0300
@@ -60,6 +60,8 @@

 modprobe -q dm-mod

+vgchange -ay
 activate_vg "\$ROOT"
 activate_vg "\$resume"
update-initramfs -k all -u