[devscripts] Parametrize devscripts's ext_iface

Replace the hardcoded value with a variable.
This value may need changes for SNO BM cases.

Signed-off-by: Bohdan Dobrelia <bdobreli@redhat.com>

Author: bogdando

docs/dictionary/en-custom.txt

@@ -524,6 +524,7 @@ rpmss
 rsa
 rsync
 runtime
+RHCOS
 scansettingbinding
 scap
 scp

roles/devscripts/README.md

@@ -50,6 +50,9 @@ networks.
 * `cifmw_devscripts_external_net` (dict) Key/value pair containing information
   about the network infrastructure.
   Refer [section](#supported-keys-in-cifmw_devscripts_external_net).
+* `cifmw_devscripts_ext_iface` (str) The network interface name used in the
+  NMState static IP template for OCP nodes. Defaults to `enp2s0`. Override for
+  bare metal hosts whose RHCOS interface name differs (e.g. `eno12399`).
 * `cifmw_devscripts_cinder_volume_pvs` (list) a list of physical disks to be
   used for creating cinder-volumes volume-group. By default, the list contains
   `/dev/vda`.

roles/devscripts/defaults/main.yml

@@ -68,6 +68,8 @@ cifmw_devscripts_create_logical_volume: false
 cifmw_devscripts_cinder_volume_pvs:
   - /dev/vda
 
+cifmw_devscripts_ext_iface: "enp2s0"
+
 cifmw_devscripts_config_overrides: {}
 cifmw_devscripts_installer_timeout: 7200  # 2 hours
 cifmw_devscripts_etcd_slow_profile: true

roles/devscripts/templates/nmstate.j2

@@ -1,6 +1,6 @@
 networkConfig:
   interfaces:
-    - name: enp2s0
+    - name: {{ cifmw_devscripts_ext_iface }}
       type: ethernet
       state: up
 {% if cifmw_devscripts_config.ip_stack != 'v6' %}
@@ -25,4 +25,4 @@ networkConfig:
     config:
       - destination: 0.0.0.0/0
         next-hop-address: "{{ net_gateway }}"
-        next-hop-interface: enp2s0
+        next-hop-interface: {{ cifmw_devscripts_ext_iface }}