To update the present cluster host proxmox following files need to be updated:
/etc/network/interfaces /etc/hosts /etc/pve/corosync.conf (only on one node necessary)
However, corosync.conf needs special way to edit the file!
Editing the corosync.conf file is not always very straightforward. There are two on each cluster node, one in /etc/pve/corosync.conf and the other in /etc/corosync/corosync.conf. Editing the one in our cluster file system will propagate the changes to the local one, but not vice versa. The configuration will get updated automatically as soon as the file changes. This means changes which can be integrated in a running corosync will take effect immediately. So you should always make a copy and edit that instead, to avoid triggering some unwanted changes by an in-between safe.
cp /etc/pve/corosync.conf /etc/pve/corosync.conf.new
Then open the config file with your favorite editor, nano and vim.tiny are preinstalled on any Proxmox VE node for example.
Always increment the config_version number on configuration changes, omitting this can lead to problems. After making the necessary changes create another copy of the current working configuration file. This serves as a backup if the new configuration fails to apply or makes problems in other ways.
cp /etc/pve/corosync.conf /etc/pve/corosync.conf.bak
Then move the new configuration file over the old one:
mv /etc/pve/corosync.conf.new /etc/pve/corosync.conf
You may check with the commands
systemctl status corosync journalctl -b -u corosync
If the change could be applied automatically. If not you may have to restart the corosync service via:
systemctl restart corosync