[libvirt-users] Need help with [virt net-create]

[Daniel P. Berrange]

On Tue, May 20, 2014 at 01:59:42AM -0700, Srinivas_G_Gowda at dell.com wrote:
> Is it possible to configure 2 virtual nics in the same ip range ?

Nope, that's unsupported. We need to key various things off the
IP address + mask used for the NIC, so you can't have multiple
nets with the same address + mask.

> Here is what I am trying.
> 
> 
> **** This works ****************
> cat nw1.xml
> <network>
>   <name>nw1</name>
>   <domain name='nw1' />
>   <forward mode='nat' dev='eth2'/>
>   <ip address='192.168.101.1' netmask='255.255.255.0'>
>     <dhcp>
>       <range start='192.168.101.128' end='192.168.101.254'/>
>     </dhcp>
>   </ip>
> </network>
> 
> 
> [root at localhost nw]# virsh net-create nw1.xml
> Network nw1 created from nw1.xml
> 
> [root at localhost nw]# virsh net-list --all
>  Name                 State      Autostart     Persistent
> ----------------------------------------------------------
>  nw1                  active     no            no
>  default              active     yes           yes
> 
> 
> 
> ****** FAILS when given the same ip address range of an existing virtual interface *******
> [root at localhost nw]# cat nw2.xml
> <network>
>   <name>nw2</name>
>   <domain name='nw2' />
>   <forward mode='nat' dev='eth2'/>
>   <ip address='192.168.101.1' netmask='255.255.255.0'>
>     <dhcp>
>       <range start='192.168.101.128' end='192.168.101.254'/>
>     </dhcp>
>   </ip>
> </network>
> 
> [root at localhost nw]# virsh net-create nw2.xml
> error: Failed to create network from nw2.xml
> error: internal error: Network is already in use by interface virbr1
> 
> 
> 
> ****** PASS - on giving diff ip range *******
> [root at localhost nw]# cat nw3.xml
> <network>
>   <name>nw3</name>
>   <domain name='nw3' />
>   <forward mode='nat' dev='eth2'/>
>   <ip address='192.168.102.1' netmask='255.255.255.0'>
>     <dhcp>
>       <range start='192.168.102.128' end='192.168.102.254'/>
>     </dhcp>
>   </ip>
> </network>
> 
> 
> [root at localhost nw]# virsh net-create nw3.xml
> Network nw3 created from nw3.xml
> 
> [root at localhost nw]# virsh net-list --all
>  Name                 State      Autostart     Persistent
> ----------------------------------------------------------
>  nw1                  active     no            no
>  nw3                  active     no            no
>  default              active     yes           yes
> 
> Any suggestions on what could be wrong here ?

Can you instead explain why you're trying to setup multiple
networks with the same IP addr/mask in the first place.


Regards,
Daniel
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