[IRONIC] - Various questions around network features.

Gaël THEROND gael.therond at bitswalk.com
Sun Jul 10 23:28:36 UTC 2022

I everyone, I’m currently working back again with Ironic and it’s amazing!

However, during our demo session to our users few questions arise.

We’re currently deploying nodes using a private vlan that can’t be reached
from outside of the Openstack network fabric (vlan 101 -
and everything is fine with this provisioning network as our ToR switch all
know about it and other Control plan VLANs such as the internal APIs VLAN
which allow the IPA Ramdisk to correctly and seamlessly be able to contact
the internal IRONIC APIs.

(When you declare a port as a trunk allowed all vlan on a aruba switch it
seems it automatically analyse the CIDR your host try to reach from your
VLAN and route everything to the corresponding VLAN that match the
destination IP).

So know, I still get few tiny issues:

1°/- When I spawn a nova instance on a ironic host that is set to use flat
network (From horizon as a user), why does the nova wizard still ask for a
neutron network if it’s not set on the provisioned host by the IPA ramdisk
right after the whole disk image copy? Is that some missing development on
horizon or did I missed something?

2°/- In a flat network layout deployment using direct deploy scenario for
images, am I still supposed to create a ironic provisioning network in

>From my understanding (and actually my tests) we don’t, as any host booting
on the provisioning vlan will catch up an IP and initiate the bootp
sequence as the dnsmasq is just set to do that and provide the IPA ramdisk,
but it’s a bit confusing as many documentation explicitly require for this
network to exist on neutron.

3°/- My whole Openstack network setup is using Openvswitch and vxlan
tunnels on top of a spine/leaf architecture using aruba CX8360 switches
(for both spine and leafs), am I required to use either the
networking-generic-switch driver or a vendor neutron driver ? If that’s
right, how will this driver be able to instruct the switch to assign the
host port the correct openvswitch vlan id and register the correct vxlan to
openvswitch from this port? I mean, ok neutron know the vxlan and
openvswitch the tunnel vlan id/interface but what is the glue of all that?

4°/- I’ve successfully used openstack cloud oriented CentOS and debian
images or snapshot of VMs to provision my hosts, this is an awesome
feature, but I’m wondering if there is a way to let those host cloud-init
instance to request for neutron metadata endpoint?

I was a bit surprised about the ironic networking part as I was expecting
the IPA ramdisk to at least be able to set the host os with the appropriate
network configuration file for whole disk images that do not use encryption
by injecting those information from the neutron api into the host disk
while mounted (right after the image dd).

All in all I really like the ironic approach of the baremetal provisioning
process, and I’m pretty sure that I’m just missing a bit of understanding
of the networking part but it’s really the most confusing part of it to me
as I feel like if there is a missing link in between neutron and the host
HW or the switches.

Thanks a lot anyone that will take time to explain me this :-)
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