[Openstack] [OpenStack][Nova] Question regarding multiple network interfaces

Leander Bessa Beernaert leanderbb at gmail.com
Wed Aug 8 10:05:11 UTC 2012


So i have set up a small proof of concept, one controller node and two
compute nodes. Since the switches do not support VLAN i'm using flat dhcp.
Each machine has two network interfaces. Eth0 is connected to the public
switch and eth1 to the private switch. The private switch has no access to
the internet.

Both compute nodes have the value of cat /proc/sys/net/ipv4/ip_forward set
to 1. However, i still can't make an instance connect to the outside.

 Any thoughts?
On Tue, Aug 7, 2012 at 11:32 PM, Sébastien Han <han.sebastien at gmail.com>wrote:

> It's part of the operating system
>
> # echo 1 > /proc/sys/net/ipv4/ip_forward
>
> Then edit your /etc/sysctl.conf and uncomment net.ipv4.ip_forward=1 to
> make this persistent after reboot.
>
> Finally run --> # sysctl -p
>
> That's all, cheers!
>
>
> On Tue, Aug 7, 2012 at 11:50 PM, Leander Bessa Beernaert
> <leanderbb at gmail.com> wrote:
> > Is there a flag in the nova.conf file or is this something that needs to
> be
> > done on the operating system?
> >
> >
> > On Tue, Aug 7, 2012 at 8:26 PM, Sébastien Han <han.sebastien at gmail.com>
> > wrote:
> >>
> >> Hi,
> >>
> >> If eth0 is connected to the public switch and if eth1 is connected to
> >> the private switch you can enable the ipv4 forwarding on the compute
> >> node. Thanks to this the VMs will have access to the outside world and
> >> the packet will be routed from eth1 to eth0 :).
> >>
> >> Cheers!
> >>
> >> On Tue, Aug 7, 2012 at 5:18 PM, Leander Bessa Beernaert
> >> <leanderbb at gmail.com> wrote:
> >> > Hello,
> >> >
> >> > I have a question regarding the use of two network interfaces.
> According
> >> > to
> >> > the official documentation, one of the interfaces is used for public
> >> > access
> >> > and the other for internal access (inter-vm communication). What i'd
> >> > like to
> >> > know is how does an instance connect to the outside world (internet
> >> > access)?
> >> > Is it done through the switch connected to the private interface or
> the
> >> > public interface?
> >> >
> >> > --
> >> > Cumprimentos / Regards,
> >> > Leander
> >> >
> >> > _______________________________________________
> >> > Mailing list: https://launchpad.net/~openstack
> >> > Post to     : openstack at lists.launchpad.net
> >> > Unsubscribe : https://launchpad.net/~openstack
> >> > More help   : https://help.launchpad.net/ListHelp
> >> >
> >
> >
> >
> >
> > --
> > Cumprimentos / Regards,
> > Leander
>



-- 
Cumprimentos / Regards,
Leander
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