DMVPN + MPLS best-path selection

Question

Dear Community
We're in the process of deploying DMVPN as a backup solution to MPLS. All that is working great!
The DMVPN wan is dual-cloud, with 2 hub routers in each cloud. Phase 3 (nhrp shortcut) is enabled on all the spokes.
For routing, all the customer subnets are advertised in MPLS, whereas for DMVPN hub advertises only a summary to 10.0.0.0/8. The protocol for both is BGP. For DMVPN, the hub routers resides in one AS (65002) and all the spokes another common AS 65102. DMVPN is therefore peered eBGP hub > spoke.
For customers connected to MPLS, the DMVPN serves as backup only solution. Best-path selection by longest prefix match.
We have other customers coming on board who wish to join the same WAN but don't have the $$$ for MPLS so are opting for DMVPN only.
Now, I have a requirement to enable spoke-to-spoke for a DMVPN only site (spokeA) to an MPLS site (spokeB). The problem is it doesn't seem to work properly as the hub router sees the best path to spokeB site via MPLS, not via DMVPN. The spoke-to-spoke is never formed, and remains spokeA > hub > mpls > spokeB. The return path is better = spokeB > DMVPN > hub > spokeA (this is because spokeB sees no route from MPLS for spokeA, so follows 10.0.0.0/8) route.
I look for any feedback that can help to meet this requirement?
And if any advice on the general design would be really appreciated.
Thanks a lot!
Phil

Answer 1

Phil, 
I did a short lab around this ... wanted to make sure I'm not saying something stupid. 
While I can't claim it's the _optimal_ solution for your setup it seems to work in my lab.
Spoke1 LAN 192.168.101.0/24 (AS 65001)
Spoke2 LAN 192.168.102.0/24 (AS 65002)
HUB LAN 192.168.111.0/24 (AS 65000)
192.168.1.0/24 DMVPN subnet. 
A single (i)VRF - DMVPN exists on hub, only and is assigned only to DMVPN tunnel interface. 
Excuse a few hacks a had to use... default routed via default-originate for example :-)
Hub
R10-P#sh run int tu0
Building configuration...
Current configuration : 281 bytes
interface Tunnel0
vrf forwarding DMVPN
ip address 192.168.1.1 255.255.255.0
no ip redirects
ip nhrp map multicast dynamic
ip nhrp network-id 1
ip nhrp shortcut
ip nhrp redirect
tunnel source Loopback0
tunnel mode gre multipoint
tunnel protection ipsec profile PRO
end
R10-P#sh run | s r b
router bgp 65000
bgp log-neighbor-changes
network 192.168.111.0
redistribute static
neighbor 10.112.112.1 remote-as 65001
neighbor 10.112.112.1 route-map SPOKES_MPLS in
default-information originate
address-family ipv4 vrf DMVPN
neighbor 192.168.1.101 remote-as 65001
neighbor 192.168.1.101 activate
neighbor 192.168.1.102 remote-as 65002
neighbor 192.168.1.102 activate
exit-address-family
R10-P#sh run | s vrf defini
vrf definition DMVPN
rd 1:1
route-target export 100:1
route-target import 100:1
address-family ipv4
  import ipv4 unicast map DEFAULT
  export ipv4 unicast map SPOKE_SUBNETS
route-target export 100:1
route-target import 100:1
exit-address-family
address-family ipv6
route-target export 100:1
route-target import 100:1
exit-address-family
Result on spoke
R1-PE#traceroute 192.168.102.1 source e2/0
Type escape sequence to abort.
Tracing the route to 192.168.102.1
VRF info: (vrf in name/id, vrf out name/id)
1 192.168.1.1 [AS 65000] 5 msec 10 msec 2 msec
2 192.168.1.102 [AS 65000] 4 msec * 5 msec
R1-PE#traceroute 192.168.102.1 source e2/0
Type escape sequence to abort.
Tracing the route to 192.168.102.1
VRF info: (vrf in name/id, vrf out name/id)
1 192.168.1.102 [AS 65000] 6 msec * 6 msec
routing on hub 
(sanitized)
R10-P# sho ip route
Gateway of last resort is 10.100.100.2 to network 0.0.0.0
S* 0.0.0.0/0 [1/0] via 10.100.100.2
10.0.0.0/8 is variably subnetted, 13 subnets, 2 masks
B 192.168.101.0/24 [20/0] via 10.112.112.1, 00:06:40
B 192.168.102.0/24 [20/0] via 192.168.1.102 (DMVPN), 00:00:03
192.168.111.0/24 is variably subnetted, 2 subnets, 2 masks
R10-P# sho ip route vrf DMVPN
Routing Table: DMVPN
Gateway of last resort is 10.100.100.2 to network 0.0.0.0
B* 0.0.0.0/0 [20/0] via 10.100.100.2, 00:06:40
192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.1.0/24 is directly connected, Tunnel0
L 192.168.1.1/32 is directly connected, Tunnel0
B 192.168.101.0/24 [20/0] via 192.168.1.101, 00:06:40
B 192.168.102.0/24 [20/0] via 192.168.1.102, 00:06:25