Delete kernel default route as seen in cumulus


1 Where do we add the default route for data plane and not management
2 How do i delete a kernel default route as seen in ip route show..i need to add a new default route for the data traffic but the gateway given under eth0 in interfaces file for management also routes data traffic and can never be removed

Thanks and appreciate as confused on routing for data traffic ie from hosts VM traffic

3 replies

Userlevel 4
Hey Mac,

I would highly recommend 'leaving' the default route for your oob, but using management VRF to separate your control plane and data plane traffic.

https://docs.cumulusnetworks.com/display/DOCS/Management+VRF

If running 3.2 you can now use NCLU (easy command line) or you add the following stanza

auto mgmt
iface mgmt
address 127.0.0.1/8
vrf-table auto


Then add vrf mgmt under eth0

auto eth0
iface eth0 inet dhcp
vrf mgmt
Then reboot. This keeps the Kernel route from showing up in the main (default) routing table. There is now two route tables, mgmt and main.

You can see them both with
  • ip route show - shows data plane routing
  • ip route show vrf mgmt - shows eth0 control plane traffic
Thanks...but if we have 3.1.2 ...would we just isolate the management VRF ?
https://docs.cumulusnetworks.com/display/CL31/Management+VRF

and after reboot any route we add goes to the main table ?

Userlevel 4
Yeah 3.1 and later is fine for management VRF.

and after reboot any route we add goes to the main table ?

By default any route will go into the main vrf unless you tell it specifically otherwise. Usually customers will advertise a default from their CE (customer edge) down to their data center devices so the 'default" is learned via OSPF or BGP. Some customers just set a static up. Really depends on your situation.

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