Introduce iptables_package var

on RHEL-9 there is no iptables package, we need to install
iptables-nft package here.

In CentOS Stream-9 and Fedora-34 onwards iptables-nft package
is available.[1]

But we also need to support other distros, so we are introducing
iptables_packages var and distro specific var files (having different
name) for installing iptables package.

[1]. https://pkgs.org/download/iptables-nft

Signed-off-by: Chandan Kumar (raukadah) <chkumar@redhat.com>
Change-Id: I8d5d3182996fc1e83b7f4f7eb99cf4c347d6ef1f

roles/multi-node-firewall/README.rst

@@ -1,2 +1,10 @@
-Configures the inventory private and public addresses in a multi-node job in
+Multinode firewall is configured.
-iptables in order to allow traffic to and from each node without restrictions.
+
+This role is intended to install iptables and configure firewall.
+
+**Role Variables**
+
+.. zuul:rolevar:: iptables_package
+   :default: iptables
+
+   Install the distribution package for Iptables.

roles/multi-node-firewall/defaults/main.yaml

@@ -0,0 +1,2 @@
+---
+iptables_package: "iptables"

roles/multi-node-firewall/tasks/main.yaml

@@ -1,7 +1,16 @@
-- name: Ensure iptables
+- name: Include operating system specific vars
+  include_vars: "{{ zj_distro_os }}"
+  with_first_found:
+    - "{{ ansible_distribution }}.yaml"
+    - "{{ ansible_os_family }}.yaml"
+    - "default.yaml"
+  loop_control:
+    loop_var: zj_distro_os
+
+- name: 'Ensure {{ iptables_package }}'
   become: true
   package:
-    name: iptables
+    name: "{{ iptables_package }}"
 
 - name: Set up the host ip addresses
   set_fact:

roles/multi-node-firewall/vars/CentOS.yaml

@@ -0,0 +1,7 @@
+---
+iptables_package: >-
+  {% if ansible_distribution_major_version|int <= 8 -%}
+  iptables
+  {%- else -%}
+  iptables-nft
+  {%- endif %}

roles/multi-node-firewall/vars/Fedora.yaml

@@ -0,0 +1,7 @@
+---
+iptables_package: >-
+  {% if ansible_distribution_major_version|int <= 33 -%}
+  iptables
+  {%- else -%}
+  iptables-nft
+  {%- endif %}

roles/multi-node-firewall/vars/RedHat.yaml

@@ -0,0 +1,7 @@
+---
+iptables_package: >-
+  {% if ansible_distribution_major_version|int <= 8 -%}
+  iptables
+  {%- else -%}
+  iptables-nft
+  {%- endif %}

roles/multi-node-firewall/vars/default.yaml

@@ -0,0 +1,2 @@
+---
+iptables_package: "iptables"