[libvirt] [RFC] net-dhcp-leases: Query: Reg: Leases API Script

Daniel P. Berrange berrange at redhat.com
Tue Oct 22 15:15:13 UTC 2013


On Tue, Oct 22, 2013 at 04:15:37PM +0530, Nehal J Wani wrote:
> Q1. The --dhcp-script option will require libvirt to provide a script
> or executable file to be run. Now as the man page says, this file is
> executed "Whenever a new DHCP  ease is created, or an old one
> destroyed". Life was easy with the script, as it used the command sed
> to remove the destroyed lease. eblake had suggested me to use a C
> program instead. So I wanted to finalize whether to go with C or
> continue with shell script.

Libvirt aims to avoid shell code whereever possible, since it is really
a very bad language from terms of reliability and security. eg quoting
rules are easy to get wrong, error handling is awful, portability is
non-trivial.

> Q2. The above executable file will be writing the custom formatted
> lease parameters to a file "dnsmasq-ip-mac.status" (suggestion open
> for name). This newly created/updated file will be parsed by the API.
> We need to decide the format for the file. Do we continue with space
> separated parameters as before?

Ideally do not invent any new format - use a format that we already
have a parser for - eg the src/util/virconf.h or src/util/virkeyfile.h
APIs for loading configs.

> Q3. What should be the location of the above two files? Is there any
> example that I can follow in libvirt for deploying custom-script
> files/C programs which are not to be linked?

We aim to put such state in /var/lib/libvirt/network/ if it needs
to survive reboots, or /var/run/libvirt/network if it does not
need to survive reboots


Daniel
-- 
|: http://berrange.com      -o-    http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org              -o-             http://virt-manager.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org       -o-       http://live.gnome.org/gtk-vnc :|




More information about the libvir-list mailing list