From 9029653baa84d8e2f9eb79a363fe97d800c1a732 Mon Sep 17 00:00:00 2001
From: Maor Blaustein <mblue@redhat.com>
Date: Tue, 5 May 2026 16:45:13 +0300
Subject: [PATCH] Add eBGP leaf template support for BGP dt02

Allow parameterized leaf ASN and downlink peering mode in the
leaf FRR template. Conditional route-reflector-client for iBGP
racks only, since FRR rejects it on eBGP peers (different ASN).

Adds ebgp_racks and ebgp_leaf_asn variables to control which
racks use eBGP and their leaf ASN (formula: 64999 - rack_id).
Applies to both IPv4 and IPv6 address families.

Adds bgp_dt02 template symlink for ci_gen_kustomize_values.

Related: OSPRH-28085
Assisted-By: Claude Code
Signed-off-by: Maor Blaustein <mblue@redhat.com>
---
 playbooks/bgp/prepare-bgp-spines-leaves.yaml    |  5 +++++
 playbooks/bgp/templates/leaf-frr.conf.j2        | 17 +++++++++++++----
 .../ci_gen_kustomize_values/templates/bgp_dt02  |  1 +
 3 files changed, 19 insertions(+), 4 deletions(-)
 create mode 120000 roles/ci_gen_kustomize_values/templates/bgp_dt02

diff --git a/playbooks/bgp/prepare-bgp-spines-leaves.yaml b/playbooks/bgp/prepare-bgp-spines-leaves.yaml
index 53bea8643..db42a5ead 100644
--- a/playbooks/bgp/prepare-bgp-spines-leaves.yaml
+++ b/playbooks/bgp/prepare-bgp-spines-leaves.yaml
@@ -453,6 +453,11 @@
     leaf_id: "{{ (ansible_hostname.split('-')[-1] | int) % 2 }}"  # always 2 leaves per rack
     rack_id: "{{ (ansible_hostname.split('-')[-1] | int) // 2 }}"  # always 2 leaves per rack
     _ip_version: "{{ ip_version | default(4) | int }}"
+    # ebgp_racks: comma-separated rack IDs that use eBGP (e.g. "1,2")
+    # ebgp_leaf_asn: base ASN for eBGP leaves (default: 64999 - rack_id)
+    _is_ebgp_rack: "{{ (rack_id | int) in (ebgp_racks | default('') | split(',') | select | map('int') | list) }}"
+    downlink_remote_as: "{{ 'external' if _is_ebgp_rack else 'internal' }}"
+    leaf_asn: "{{ ebgp_leaf_asn | default(64999 - (rack_id | int)) if _is_ebgp_rack else 64999 }}"
   tasks:
     - name: Obtain the connection for the eth0 interface
       ansible.builtin.command:
diff --git a/playbooks/bgp/templates/leaf-frr.conf.j2 b/playbooks/bgp/templates/leaf-frr.conf.j2
index d4405b0c4..c72568913 100644
--- a/playbooks/bgp/templates/leaf-frr.conf.j2
+++ b/playbooks/bgp/templates/leaf-frr.conf.j2
@@ -13,12 +13,15 @@ debug bgp neighbor-events
 debug bgp updates
 debug bgp update-groups
 
-router bgp 64999
+{% set _downlink_as_mode = downlink_remote_as | default('internal') %}
+router bgp {{ leaf_asn | default(64999) }}
 {% if _router_id %}
   bgp router-id {{_router_id}}
 {% endif %}
   bgp log-neighbor-changes
+{% if _downlink_as_mode == 'internal' %}
   bgp graceful-shutdown
+{% endif %}
 
   bgp graceful-restart
   bgp graceful-restart notification
@@ -27,7 +30,7 @@ router bgp 64999
   ! bgp long-lived-graceful-restart stale-time 15
 
   neighbor downlink peer-group
-  neighbor downlink remote-as internal
+  neighbor downlink remote-as {{ _downlink_as_mode }}
   neighbor downlink bfd
   neighbor downlink bfd profile tripleo
 {# TODO: remove the next if when RHEL-63205 is fixed #}
@@ -53,9 +56,11 @@ router bgp 64999
 
   address-family ipv4 unicast
     redistribute connected
-    neighbor downlink route-reflector-client
     neighbor downlink default-originate
     neighbor downlink next-hop-self
+{% if _downlink_as_mode == 'internal' %}
+    neighbor downlink route-reflector-client
+{% endif %}
     neighbor downlink prefix-list only-host-prefixes out
     neighbor uplink allowas-in origin
     neighbor uplink prefix-list only-default-host-prefixes in
@@ -64,9 +69,11 @@ router bgp 64999
   address-family ipv6 unicast
     redistribute connected
     neighbor downlink activate
-    neighbor downlink route-reflector-client
     neighbor downlink default-originate
     neighbor downlink next-hop-self
+{% if _downlink_as_mode == 'internal' %}
+    neighbor downlink route-reflector-client
+{% endif %}
     neighbor uplink activate
     neighbor uplink allowas-in origin
     neighbor uplink prefix-list only-default-host-prefixes in
@@ -76,7 +83,9 @@ router bgp 64999
     neighbor uplink activate
     neighbor uplink allowas-in origin
     neighbor downlink activate
+{% if _downlink_as_mode == 'internal' %}
     neighbor downlink route-reflector-client
+{% endif %}
   exit-address-family
 
 ip prefix-list only-default-host-prefixes permit 0.0.0.0/0
diff --git a/roles/ci_gen_kustomize_values/templates/bgp_dt02 b/roles/ci_gen_kustomize_values/templates/bgp_dt02
new file mode 120000
index 000000000..5df68da8a
--- /dev/null
+++ b/roles/ci_gen_kustomize_values/templates/bgp_dt02
@@ -0,0 +1 @@
+bgp_dt01
\ No newline at end of file