[IDEA] xendhcp proposal

[George Shuklin <george.shuklin@gmail.com>]

Good day.

During automated VM deploy I found some very annoying problem - network 
VM configuration. Classic DHCP is not very easy to manage in virtual 
environment (protection from stray DHCP-servers, problems with 
autoidentification).

Problems are:
* how to identificate VM?
* how to provide network configuration in native way for guest (e.g. 
support of mount order for network fs, if-up scripts and so on)
* how to reconfigure hosts 'on demand'? (even DHCP is not very 'on 
demand' beause of lease time).

Propose:

Store network configuration in domain part of xenstore, use xendhcp 
service to read those data from guest and acts like classic dhcp client.

Implementation detail:

1) Store data in DHCP-like way (option code - answer).
2) Subscribe for changes and reacts to it like we have lease expiration.
3) xendhcp should replace normal dhcp (may be even with conclict in 
packages with original dhcp client, and provide it functionality), mimic 
/sbin/dhclient functionality.

That allows to keep original network configuration for every 
distribution, just put 'dhcp' method for debian 'interfaces' (and same 
way for every other operation system).

What you think about this?