Bypassing backup and restore when upgrading

The following is only for advanced users which have knowledge about Proxmox configuration files!

Since Backup and Restore can be a time-consuming process in the following a more rapid method is described - possible only if the (virtual) disk(s) for the VM(s) is (are) located at a storage which is not touched by the installation process (e.g. NFS at an external server)

The steps

• Backup all VMs
• Restore full VMs from Backups

will be replaced by

• Backup <vmid>.conf file(s) for the respective machine(s), they are located under /etc/pve/nodes/<nodename>/lxc/ and /etc/pve/nodes/<nodename>/qemu-server/ respectively
• Backup those storages from the storage configuration ( /etc/pve/storage.cfg ) which are shared and untouched, simply copy the respective lines and append them once to the newly build clusters /etc/pve/storage.cfg
• Restore <vmid>.conf file(s) for the respective machine(s)

Note: /etc/pve/lxc/ and /etc/pve/qemu-server/ are virtual symlinks for the current nodes lxc and qemu directory.

After you restored the VM configs and restored the external shared Storage configuration - so that it is accessible under the same name in the new cluster again - you should be able to start the VMs again. No additional reboot is required.