[Rdo-list] 10 days of rdo manager

James Slagle jslagle at redhat.com
Mon Apr 20 23:58:21 UTC 2015

On Mon, Apr 20, 2015 at 03:48:51PM -0700, Dan Sneddon wrote:
> On 04/20/2015 03:42 PM, James Slagle wrote:
> > On Mon, Apr 20, 2015 at 06:49:27PM +0100, Pedro Sousa wrote:
> >> Hi,
> >>
> >> I haven't played with it yet, but I would like to know what happens to
> >> overcloud nodes when you reboot/loose or break your undercloud node.
> >>
> >> Do overcloud nodes loose ip connectivity? My understanding is that
> >> overcloud nodes get dhcp from Neutron. Or do I need to have some HA for
> >> undercloud in place?
> > 
> > With the network architecture we're moving towards, overcloud nodes will only
> > get dhcp from Neutron for the provisioning network. The api, data, storage, etc
> > network will support static IP configuration, or possibly, non-Neutron provided
> > dhcp.
> > 
> > Further, after initial provisioning, overcloud nodes will boot off the local
> > disk instead of pxe booting via Neutron on subsequent reboots. localboot
> > support is a relatively new feature in upstream Ironic, and we'll be enabling
> > it soon in rdo-manager.
> > 
> > With these changes, when the undercloud is stopped or goes down unexpectedly
> > the overcloud would be unaffected. That being said, we still plan to have an HA
> > undercloud at some point in the future.
> > 
> > Also, the current virt-setup that allows testing rdo-manager via deploying the
> > undercloud and overcloud all on vm's still relies on the undercloud vm to
> > continue to run for connectivity to overcloud nodes. That could also be
> > enhanced though to not require the undercloud vm to stay up.
> > 
> > 
> When a node is configured for local boot, does it get a static IP
> address? Maybe it turns the DHCP address into a static? Or does it
> still rely on the undercloud for DHCP?

The interface connected to the provisioning network will still get dhcp from
neutron on the undercloud if that interface is configured to start on boot, and
configured to try dhcp. Since we're currently including the
dhcp-all-interfaces[1] element in our image builds, that will indeed be the case.

If not, it wouldn't get any IP address. It doesn't seem like you'd want to
configure it with a static IP.

[1] https://github.com/openstack/diskimage-builder/tree/master/elements/dhcp-all-interfaces
Note we've had a few requests to not default to including this element, or at
least it make it configurable not to include it.

-- James Slagle

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