openstack team mailing list archive

[Vishvananda Ishaya <vishvananda@xxxxxxxxx>]

On Apr 25, 2012, at 7:22 PM, Atul Gosain wrote:

> Hi 
> 
>  Thanks a lot for the responses. I still have some clarifications. 
> Openstack documentation states (http://docs.openstack.org/trunk/openstack-compute/admin/content/hypervisor-configuration-basics.html)
> Hypervisor Configuration Basics
> 
> The node where the nova-compute service is installed and running is the machine that runs all the virtual machines, referred to as the compute node in this guide.
> 
> This gave me an impression that nova-compute service has to be installed on hypervisor(and not VM). 
> 
> Though from the links below, it seems that nothing needs to be installed on ESX server for openstack to manage it, from the documentation (http://wiki.openstack.org/XenServer/GettingStarted), it seems like this package needs to be built on Ubuntu and then install on XenServer for it to be managed by Openstack. 
> 
> Sorry for my confusion, but couldnt figure out from the documentation. 
> 
> -------------
> 
> Secondly, what i mainly wanted to know was that how does openstack assign IP addresses to the new VMs it creates. If i see in the API's of individual hypervisors Xen, HyperV etc doesnt provide any direct method of setting IP address on the host, though they provide to set the MAC address. Cloudstack uses an internal DHCP server to set the IP addresses in VM's for the assigned MAC. 
> 
> I looked into the openstack code, it seems like the network configuration is injected into the VM images. Is it true ? As i understand, these images are stored on Glance server. How are these images installed on hypervisors by openstack. It does need to have some software running on hypervisors to which controller can push the image of the VM. 
> 

It depends on the network mode, but the most common configuration uses a dhcp server as well.
> Where does the network information get injected inside the image ? Is it on the glance server or hypervisor ?
> 
In the injected version (not recommended) it is injected after the image is downloaded from glance on the compute host.
> 
> Thanks
> 
> Atul