PVE 9.1.1 6.17.2-2 (2025-11-26T12:33Z) on amd64

Reference docs, this forum post.

I would really recommend shutting down your guests before doing this.

Modify /etc/hosts (OR your DNS record, if you’re not using the hosts file), /etc/hostname, /etc/mailname (if applicable), /etc/postfix/main.cf:

sed -i 's/oldname/newname/g' /etc/{hosts,hostname,/postfix/main.cf}

Then, it’s simplest to stop the cluster filesystem and edit the backing database to rename the /etc/pve/nodes directory for the server.

Yes, really, though fighting the cluster FS and moving, not copying, the files in mounted /etc/pve/nodes/old to /etc/pve/nodes/new (directory by directory - you cannot move/rename a non-empty directory on the pmxcfs, so you will have to move /old/qemu-server/*, etc) should also work if this makes you squeamish.

systemctl stop pve-cluster
systemctl stop corosync

sqlite3 /var/lib/pve-cluster/config.db "UPDATE tree SET name='newname' WHERE name='oldname';"

systemctl start corosync
systemctl start pve-cluster

Finally, copy /var/lib/rrdcached/db/pve-{node,storage}/old to /var/lib/rrdcached/db/pve-{node,storage}/new, then reboot.