[ovs-discuss] [OVN] Routed provider networks

Maciej Jozefczyk mjozefcz at redhat.com
Mon Mar 30 14:53:16 UTC 2020


Hello!

I started to work on Routed Provider Networks feature for Openstack
Neutron, that is described [1].
Neutron community chosen second variant of this RFE, that would be easier
to implement for now.

To achieve this we would need to have multiple provider network segments
configured within the same Logical Switch.
I prepared an example environment [2] and tested it.

The worker hosts where VMs are placed are directly connected to provider
vlan network with segments:
external-segment-1: 172.24.4.0/24 vlan 4
external-segment-2: 172.24.6.0/24 vlan 6

Worker host have following-bridge mappings configured:
worker-1: ovn-bridge-mappings="external-segment-1:br-ex"
worker-2: ovn-bridge-mappings="external-segment-2:br-ex"
and fabric physical interfaces connected to br-ex.

In OVN both segments are connected to the same Logical_Switch 'public':
------------------------------------------------------------------------------------------------------------------------------------------------------------------
ovn-nbctl list logical_switch_port
_uuid               : e80bbfef-e966-4973-bec2-2dad6c18b09c
addresses           : [unknown]
dhcpv4_options      : []
dhcpv6_options      : []
dynamic_addresses   : []
enabled             : []
external_ids        : {}
ha_chassis_group    : []
name                : public-segment-1-localnet
options             : {network_name=external-segment-1}
parent_name         : []
port_security       : []
tag                 : []
tag_request         : []
type                : localnet
up                  : false

_uuid               : efdcbbed-dd97-4b09-9b96-0dd25a4d6f03
addresses           : [unknown]
dhcpv4_options      : []
dhcpv6_options      : []
dynamic_addresses   : []
enabled             : []
external_ids        : {}
ha_chassis_group    : []
name                : public-segment-2-localnet
options             : {network_name=external-segment-2}
parent_name         : []
port_security       : []
tag                 : []
tag_request         : []
type                : localnet
up                  : false
------------------------------------------------------------------------------------------------------------------------------------------------------------------
I also spawned 2 VMS: vm1 - in external-segment-1 and vm2 - in
external-segment-2.

*Conclusion*:
I *can* ping VMs from hosts connected to fabric [2], from host-1 I can ping
vm1 and from host-2 I can ping vm2.
I *do not see* any traffic from external-segment-1 on external-segment-2
and vice-versa.

*However I spotted some issues*:
Unfortunately the ovn-controller on worker-1 and worker-2 are continuously
logging:
>From worker-1:
patch|ERR|bridge not found for localnet port 'public-segment-2-localnet'
with network name 'external-segment-2'
>From worker-2:
patch|ERR|bridge not found for localnet port 'public-segment-1-localnet'
with network name 'external-segment-1'

*Questions*:
Can we try to log this kind of error only once in this situation?
So when there is a Logical_Switch, in which there are more than one
localnet ports added and chassis is placed in only one segment, can we
print this log only once and skip patch port plug-in until there would be
update of ovn-bridge-mappings for that chassis?
Do you find this architecture (multiple localnet ports in one
Logical_Switch) could lead us to some issues?


Thanks,
Maciej


[1] https://bugs.launchpad.net/neutron/+bug/1865889
[2] https://imgur.com/a/hEI8Nin

-- 
Best regards,
Maciej Józefczyk
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