Add infiniband feature document

Signed-off-by: Gris Ge <fge@redhat.com>

Author: cathay4t

features/infiniband.md

@@ -0,0 +1,58 @@
+<!-- vim-markdown-toc GFM -->
+
+* [Infiniband Over IP](#infiniband-over-ip)
+* [Bond Over Infiniband](#bond-over-infiniband)
+
+<!-- vim-markdown-toc -->
+
+# Infiniband Over IP
+
+This is the example YAML for creating PKEY Infiniband over IP
+
+```yml
+---
+interfaces:
+- name: mlx5_ib0.80fe
+  type: infiniband
+  state: up
+  infiniband:
+    base-iface: mlx5_ib0
+    mode: datagram
+    pkey: '0x80fe'
+```
+
+Pleas refer to [YAML API document][1] for detail meaning of each property.
+
+# Bond Over Infiniband
+
+Only the `active-backup` mode of bond is supported when attaching infiniband
+over IP to bond. Example YAML:
+
+```yml
+---
+interfaces:
+- name: mlx5_ib0.80ff
+  type: infiniband
+  state: up
+  infiniband:
+    base-iface: mlx5_ib0
+    mode: datagram
+    pkey: '0x80ff'
+- name: mlx5_ib0.80fe
+  type: infiniband
+  state: up
+  infiniband:
+    base-iface: mlx5_ib0
+    mode: datagram
+    pkey: '0x80fe'
+- name: bond0
+  type: bond
+  state: up
+  bond:
+    mode: active-backup
+    port:
+    - mlx5_ib0.80fe
+    - mlx5_ib0.80ff
+```
+
+[1]: https://nmstate.io/devel/yaml_api.html#ip-over-infiniband-interface

index.md

@@ -35,6 +35,7 @@ NetworkManager acts as the main (and currently the only) provider supported.
 - [Refer Interface using PCI Address](./features/pci_identifier.md)
 - [IPsec](./features/ipsec.md)
 - [DNS](./features/dns.md)
+- [Infiniband](./features/infiniband.md)
 
 ## Example output