add keepalived ansible role

deployment/roles/keepalived/files/check_nginx.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+STATUS_CODE=$(curl -s -o /dev/null -w "%{http_code}" http://localhost)
+
+if [ $STATUS_CODE -lt 200 ] || [ $STATUS_CODE -ge 400 ]; then
+  exit 1
+fi

deployment/roles/keepalived/tasks/main.yml

@@ -0,0 +1,25 @@
+- name: Install keepalived packages
+  apt:
+    name:
+      - keepalived
+    state: latest
+    update_cache: true
+
+- name: Copy check_nginx script to {{ vrrp_check_nginx_script_path }}
+  copy:
+    src: check_nginx.sh
+    dest: "{{ vrrp_check_nginx_script_path }}"
+    owner: root
+    group: root
+    mode: 0755
+
+- name: Copy keepalived config
+  template:
+    src: keepalived.conf.j2
+    dest: /etc/keepalived/keepalived.conf
+
+- name: Restart and enable the keepalived service
+  ansible.builtin.service:
+    name: keepalived
+    state: restarted
+    enabled: yes

deployment/roles/keepalived/templates/keepalived.conf.j2

@@ -0,0 +1,24 @@
+vrrp_script chk_nginx {
+  script "{{ vrrp_check_nginx_script_path }}"
+  interval 5
+  timeout 3
+  weight 2
+}
+
+vrrp_instance VI_1 {
+  state MASTER
+  interface {{ vrrp_interface }}
+  virtual_router_id 51
+  priority 100
+  advert_int 1
+  authentication {
+    auth_type PASS
+    auth_pass {{ vrrp_auth_password }}
+  }
+  virtual_ipaddress {
+    {{ vrrp_virtual_ip }} dev {{ vrrp_interface }}
+  }
+  track_script {
+    chk_nginx
+  }
+}