[one-users] onevnet base address

Tino Vazquez tinova at fdi.ucm.es
Mon Mar 1 07:41:01 PST 2010

Hi Tiago,

OpenNebula uses the network size to calculate the number of 1s in the
network mask:

    network_address =  0xFFFFFFFF << (int) ceil(log(size)/log(2));
    network_address &= net_addr;

Therefore, with your address and size, the network mask is last 8 bits
are 10000000, and given your net address, the first lease will be

With the net adress you can fix the first lease to, but you will have a rather small one (just 14 in size),
since you will be setting a network.



Constantino Vázquez, Grid & Virtualization Technology
Engineer/Researcher: http://www.dsa-research.org/tinova
DSA Research Group: http://dsa-research.org
Globus GridWay Metascheduler: http://www.GridWay.org
OpenNebula Virtual Infrastructure Engine: http://www.OpenNebula.org

On Fri, Feb 26, 2010 at 11:24 PM, Tiago Batista <tiagosbatista at gmail.com> wrote:
> Hello all
> I am trying to create a network configuration.
> What I want is to use the network in the following way:
> ->physical hosts
> -> virtual hosts
> Now, if I use the following vnet template, the first VM I create uses the
> address, wich would be fine if it were not the fact that it is
> causing an address collision!
> NAME = "Xen Network"
> BRIDGE = "xenbr0"
> NETWORK_SIZE    = 230
> I believe this should create a pool of 230 hosts, the first of them with a
> .20 address, am I right? If that is the case, then address generation should
> be revised as it is creating a lease for .1
> If I am wrong, then the contextualization script supplied on the web page
> should set the router to a .254 address instead of a .1 address, this to
> avoid assigning the router address to any VM... I believe this is easier to
> do than the modification above, yet I will look at the code to find out if
> it is easy to perform the modification stated above.
> Any comments on this?
> _______________________________________________
> Users mailing list
> Users at lists.opennebula.org
> http://lists.opennebula.org/listinfo.cgi/users-opennebula.org

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