anchor.diff:      .host = "<%= v[0] %>";
       .port = "<%= v[1] %>";
       .first_byte_timeout = <%= @first_byte_timeout %>;
  -# This backend is used for saint mode. Unless you know what you're doing
  -# DO NOT REMOVE
  +    .probe = backend_health_check;
   }
   <% end -%>
   
  
positive.code: # ************************************************************
  probe backend_health_check {
      .url = "<%= @health_check_url %>";
      .url = "/ping.txt"
      .timeout = <%= @health_check_timeout %>;
      .timeout = 300ms;
      .interval = <%= @health_check_interval %>;
      .interval = 1s;
      .window = <%= @health_check_window %>;
      .window = 10;
      .threshold = <%= @health_check_threshold %>;
      .threshold = 6;
      .expected_response = <%= @health_check_expected_response %>;
      .expected_response = 200;
  }
  
  # ************************************************************
  
negative.code: # Saint Mode Backend
  # https://www.varnish-software.com/static/book/Saving_a_request.html#example-evil-backend-hack
  # ************************************************************
  backend fail {
      .host = "127.0.0.1";
      .port = "12871";
      .probe = {
          .url = "/fail";
          .initial = 0;
          .interval = 1d;
      }
  }
  
  # ************************************************************
  # Director
  