Add support for FRR reload

In case of configuration changes it's better to reload FRR rather then
perform restart. Actions towards FRR lead to networking downtime until
connection is established and required routes reconciled.

To reduce the downtime let's reload FRR in case of simple config changes

Change-Id: I83746f3a101dc0f678a4a82d02160fc1fa8d8e52

handlers/main.yml

@@ -20,3 +20,14 @@
     name: frr
     state: restarted
     enabled: true
+  register: frr_restart
+
+- name: Reload frr
+  become: true
+  become_user: root
+  service:
+    name: frr
+    state: reloaded
+    enabled: true
+  when:
+    - frr_restart is not defined or (frr_restart is defined and frr_restart is skipped)

tasks/frr_post_install.yml

@@ -24,7 +24,7 @@
         regexp: '^(no)?\s?service integrated-vtysh-config$'
         line: "service integrated-vtysh-config"
         mode: "0640"
-      notify: Restart frr
+      notify: Reload frr
 
     - name: Write down integrated config
       template:
@@ -34,7 +34,7 @@
         group: frr
         mode: "0640"
         validate: /usr/bin/vtysh -C -f %s
-      notify: Restart frr
+      notify: Reload frr
 
     - name: Configure supported daemons
       lineinfile: