[pve-devel] [RFC SDN DHCP] Add and Remove DHCP mappings on vNIC add/remove

Stefan Lendl s.lendl at proxmox.com
Fri Oct 27 13:29:54 CEST 2023

Sorry, Sending this again because I noticed that I messed up the subject
prefixes for the patches.

This patch series defines IPs, once allocated by the IPAM as persistant
until the vNIC is removed from the VM or the VM is destroyed.

The dnsmasq ethers file is a pure product of the IPAM database and does
not have it's own state, therefore removing the potential issue of wrong
sync state between IPAM and dnsmasq.
Updating the ethers file is only done on the effected node.

Technically, starting the VM still adds the DHCP mapping. This is needed
at the moment because during migration, this triggers generating the
ethers file on the target node.  If the IPAM already contains the
mapping, it returns the existing IP (upsert)

Alternative approach would be to trigger an update of the ethers file on
all nodes on IPAM update.

Stopping a guest does not effect IPAM/DHCP.

Destroying a guest removes the associated IPs from the IPAM.


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