Source routing on server


#1

Hi all,
To the best of my knowledge it is impossible to setup mass to configure the server for source based routing in case the server has multiple interfaces. I believe it would be possible to do it with a preseed script that runs post install but I don’t think I can do it generic enough.

Any ideas or possible workarounds ?


#2

Hi there!

Indeed as of 2.5 you will need to modify preseeds (cloud-unit) to configure source routes.

MAAS 2.6 will feature source routing (or as we will call it, support for multiple default gateways).

A few questions. When you configure such environment, are all your machines configured with source routing or only a select few ? Or the ones that connect to multiple subnets?

@mpontillo you may have more questions?

As far as work around, I suggest you take a look at Customizing MAAS deployments with cloud-init to customize your deployments!


#3

Apart from multiple default gateways, source routing is also necessary in case of asymmetrical return paths, where by default are rejected by the linux kernel.
In my case this is a problem for almost all my servers (usually batches of 12-servers deployment at a time) as I use different vlans on different subnets with public IPs.


#4

Glad to hear this on the map for 2.6. We’re looking forward to it!

Some more details in https://bugs.launchpad.net/maas/+bug/1737428 which brought up these issues late last year.


#5

Can you give an example of what exact configuration you’re trying to achieve? (If you can create the configuration in netplan, MAAS could ultimately be convinced to convey it to a machine - assuming we add support.)

As @andreserl mentioned, we’re looking at the specific use case of “multiple default gateways”; that ends up requiring source souring to a limited degree, since you need to know which source subnets should reach out to an alternative gateway. It would be helpful to know if what we have in mind would be sufficient for you.