VARNISH : Usage of libvmod-dynamic

default.vcl

vcl 4.0;

# Add import
import dynamic;

# Probe for backend api server
probe api_probe {
  .interval = 5s;
  .timeout = 1s;
  .window = 5;
  .threshold = 3;
  .initial = 3;
}

# Define IPv4 only ACL for the module
acl ipv4_only { "0.0.0.0"/0; }

# in "vcl_init"
  new api_1 = dynamic.director(
    port = "80",
    probe = api_probe,
    ttl = 2m,
    whitelist = ipv4_only
  );

# in "vcl_recv"
  set req.backend_hint = api_1.backend("api1.domain.com");