On 03/14/2011 03:50 PM, Ian Main wrote:
On Fri, Mar 11, 2011 at 04:17:18PM -0500, John R. Dunning wrote:
From: Ian Main<imain@redhat.com> Date: Fri, 11 Mar 2011 16:04:00 -0500[...]
IP Discovery ------------ There are many possible solutions to this problem but none of them are obviously better than any other. The three that seem the most promising are: 1) Using an agent in the VMs to register with a central server thereby letting us know its IP. 2) Having control of the DHCP server so we can see which leases are out for which MACs. 3) Using a config file which maps MACs to IPs and then configuring dhcpd with the same mapping. Of these I'm thinking we should implement #3 first.3 is relatively easy. I would have thought 2 was easy, but I'm told that we can't count on it.
Well it is relatively easy for us to implement but it is not always easy to set up. Not for developers at least which is our initial target audience.
Also, presents a high barrier to entry for end users (admins), who may not be allowed to run DHCP themselves or wall off a portion of addresses.
My observation is that, immediately after you prove that you can launch an instance, you're going to need to care about configuring it. That means you need the config server, which is door number 1. So I advocate that we just bite the bullet and do that one right away. I think this should get us up and running quickly and it can be configured in almost any environment. Second option would be #1. I think in the end we will need to implement all of these and have it be configurable by the admin.
You always need 1, regardless of what other things you do.
Yes and we will get there but my understanding is that it is still a ways off in the grand scheme of things.. at least longer than I want to wait. It's also my understanding that this would integrate with Aeolus and not necessarily allow a condor cloud to stand on its own (by giving the user of condor cloud only the IP of the instance).
Other tidbit that I didn't see: We have the ability to inject some small snippet of data at launch time, correct? For instance as a karg or something? I'm pretty sure we talked about this offline, but I want to make sure (a) the answer is yes, and (b) we build it into the api.
Actually I was just looking through the code and AFAICT this is only supported for Xen based VMs, not KVM. It would be easy enough to add to condor though.. but then we are getting into needing a modified condor again. Perhaps this line of development would be useful to upstream though?
The other thing I noticed is that there is no way to override the architecture via condor. Eg run an i686 guest on x86_64 hardware.
Ian
The last hop on the user -> guest path through Condor hits libvirt. So anything you can do with libvirt you can do here. If you can pass kargs via libvirt domain XML you're ok. Same for arch etc.
Best,
matt