If you’ve reached this article, then for sure you’ve been searching for how to get Contrail (or its counterpart Tungsten Fabric) to work with a Cisco ASR9K.
One of the first links you most likely hit has been:
Contrail MX ASR903
posted in 2014 where the Cisco case is referring to IOS XE, Cisco ASR 903, which most probably, if you came here, does NOT apply to you .
One thing you have to know though, if IOS XE had a feature for building dynamic GRE tunnels, well IOS XR DOESN’T have this baked in yet. As with any vendor, based on popular demand from customers, some features get higher priority for implementing while others are left for later. This one seems to be the latter. As such, one will have to build static GRE tunnels to each Compute Node.