Re: [libvirt] RFC: Implement virDomainGetIPAddress()

[snip] Hi Daniel, I've been thinking about this a little more and maybe it would be nice to implement some communication between libvirt and the agent as well. This way the libvirt-based tools would be having track of the guest's IP address and the API like virDomainGetIPAddress() could be still a useful name for this functionality. However the guest will be optional AFAIK so that maybe some option to get the IP address using one of the other methods (like arp, leases file or capturing packets) could still be useful for the case the QEMU Guest Agent won't be running in the guest. Like mentioned, those methods are not 100% reliable but adding at least the option to support them would be a nice thing to have. This could be passed to the function using the flags argument with default to qemu guest agent. For instance, it could be using one or more of the following constants: #define VIR_DOMAIN_GUEST_AGENT 0x10 #define VIR_DOMAIN_GET_IP_PCAP 0x20 #define VIR_DOMAIN_GET_IP_DHCP_LEASES_FILE 0x40 #define VIR_DOMAIN_GET_IP_ARP 0x80 #define VIR_DOMAIN_GET_IP_TRYALL VIR_DOMAIN_GUEST_AGENT | VIR_DOMAIN_GET_IP_PCAP | VIR_DOMAIN_GET_IP_DHCP_LEASES_FILE | VIR_DOMAIN_GET_IP_ARP This could be run in the same order like mentioned here if specified all of them (VIR_DOMAIN_GET_IP_TRYALL), i.e. to test first for agent communication channel to ask for IP (this would be really nice), then try to get the packets captured on domain boot (this is being remembered somewhere IMHO), look to the DHCP leases file if DHCP is enabled and we still don't have the IP address and try to look for the ARP record once if all of above failed. If this last one fails too then we can return some error value. I find the option to expose the guest's IP address to libvirt very useful since we would be this having information accessible from any application/module that's using libvirt. The idea came to my mind when I was thinking of guest management using php-virt-control. I don't want to implement the whole VNC stack (although it would be a great experience for me - no doubt about it ;-) ) to the libvirt-php however the user won't be able to manage the guest at all if he/she doesn't know the IP address for SSH connection. Of course, there's a workaround to connect to VNC on a specified port and use VNC for this however what if remote access to guest's VNC windows will be disabled ? This is the reason why I think the option to get guest's IP address directly from libvirt would be a very nice thing to have ;-) Thanks, Michal -- Michal Novotny <minovotn(a)redhat.com&gt;, RHCE, Red Hat Virtualization | libvirt-php bindings | php-virt-control.org