Finer control over IP address assignment about flannel HOT 2 CLOSED

@mrunalp flannel works at IP (L3) layer today so it's not really possible -- the routing table would not know where to route packets. So far we're planning on keeping flannel a L3 technology as it's easier to deal with. It's possible to run multiple instances of flannel and giving them unique etcd-prefix and configuring them to use distinct UDP ports. That will result in multiple interfaces (flannel0, flannel1, ...) but you have to make sure the address ranges that your configured for them in etcd do not overlap. With VxLAN, the same should again be possible except that you can use vxlan ids instead of UDP port for segregation.

Having two containers with same IP but on different vxlans would require flannel to support L2 semantics. The trouble there is that it becomes necessary to support broadcast (for ARP). We're planning on using VxLAN encap but not it's use of multicast for broadcast. We will therefore not have a way of doing broadcast. We may support a limited L2 functionality without broadcast that relies on flannel to do proxy ARP.

from flannel.

Closing as the question is answered - Flannel is L3 only.

from flannel.