proxmox apply network changes without reboot

Proxmox, one of the available virtualization infrastructure managers in linux , got for newbees a big issue the “must reboot to appy changes” .

This issues causes , obviously , the reboot of a production server that causes a down for a non critical change – OK any change on network interfaces is critical , but for sure not so critical if we think about reboot + changes – . A good infrastruture got at least a trunk on LAN not on public network branch , bonded or not , that can be leaved alone during networking changes, this is a “must” to have a backdoor to connect to server if any trouble happens on WAN bridge/interface .

If you , the reader , are a newbee don’t go further, reading more about it can causes the will to try , and if you will try i’m sure that you would like to try on super critical system .

Let’s start :

Proxmox create a diff file for the changes that must applied to interfaces configuration file that is “interfaces.new” the diff will be applyed , during normal boot via the “pvenetcommit” init script .

#/etc/init.d/pvenetcommit start

this command will apply the diff and remove the “.new” file from /etc/network/ directory. Now we have a modified interfaces file ready to be applyed , so simply apply network changes using the standard and well known init script

#/etc/init.d/networking restart

now we have a system with the new network settings without any downtime ( if the settings applied are correct ) if not , you have the backdoor way to login to the system to correct any error or misconfiguration applied .

This steps are good if you want to add/remove bridges/interfaces/bondings , enable or disable interfaces/bridges/bondings , but as i can see don’t apply any change in VLAN interfaces and setting , at least the interfaces file will be correct , the interfaces settings running will be correct but the aded VLAN interfaces ( vmbr0v10 ) still remain UP , you will must put DOWN by yourself via the standard ifconfig command

#ifconfig vmbr1v10 down

after done that you will have a full up and running brand new configuration , and at least after a rebbot you will more relaxed , sure when the server is not in requests peak time .