Upgrade Proxmox VE from version 8 to 9

The procedure is described in detail on the official wiki. I will now summarize it briefly and clearly. I am assuming use without a subscription, as is common in a private setting.

Requirements

• PVE 8 must be updated to the latest possible version, at least v8.4.1.
• SSH access is recommended.
• For safety reasons, back up everything.
• At least 5 GB of free space in the root partition, preferably 10 GB.

When using Proxmox Backup Server or Ceph, there are a few more things to consider.

Let’s go…

The Proxmox team has really simplified the process. There is a script that automatically checks whether everything is ready for an upgrade. You can run it with the following command:

pve8to9 --full

pve8to9 --full

If problems arise, the easiest thing to do is to google the issues. I didn’t encounter any serious problems. Then continue with these commands, one after the other:

apt update
apt dist-upgrade
pveversion

apt update
apt dist-upgrade
pveversion

The version displayed at the end should be at least 8.4.1, as mentioned above. Now the repositories are adjusted:

sed -i 's/bookworm/trixie/g' /etc/apt/sources.list
sed -i 's/bookworm/trixie/g' /etc/apt/sources.list.d/pve-enterprise.list

sed -i 's/bookworm/trixie/g' /etc/apt/sources.list
sed -i 's/bookworm/trixie/g' /etc/apt/sources.list.d/pve-enterprise.list

The new PVE 9 repository in deb822 format can be added as follows (No Subscription!):

cat > /etc/apt/sources.list.d/proxmox.sources << EOF
Types: deb
URIs: http://download.proxmox.com/debian/pve
Suites: trixie
Components: pve-no-subscription
Signed-By: /usr/share/keyrings/proxmox-archive-keyring.gpg
EOF

cat > /etc/apt/sources.list.d/proxmox.sources << EOF
Types: deb
URIs: http://download.proxmox.com/debian/pve
Suites: trixie
Components: pve-no-subscription
Signed-By: /usr/share/keyrings/proxmox-archive-keyring.gpg
EOF

You can then check whether it works with:

apt update
apt policy

apt update
apt policy

The repository must also be updated for Ceph (No Subscription!):

cat > /etc/apt/sources.list.d/ceph.sources << EOF
Types: deb
URIs: http://download.proxmox.com/debian/ceph-squid
Suites: trixie
Components: no-subscription
Signed-By: /usr/share/keyrings/proxmox-archive-keyring.gpg
EOF

cat > /etc/apt/sources.list.d/ceph.sources << EOF
Types: deb
URIs: http://download.proxmox.com/debian/ceph-squid
Suites: trixie
Components: no-subscription
Signed-By: /usr/share/keyrings/proxmox-archive-keyring.gpg
EOF

apt update
apt policy

apt update
apt policy

The biggest and final step follows now:

apt dist-upgrade

apt dist-upgrade

A lot of work is currently being done, and after a final restart, the upgrade to PVE 9 should have gone smoothly. After that, you can search for updates in the web GUI as usual; none should be found.