public static String getLocalCanonicalHostName() {
        try {
            return InetAddress.getLocalHost().getCanonicalHostName();
        } catch (final UnknownHostException ignored) {
            return getLocalHostName();
        }
    }
Gets the fully qualified domain name for this IP address.
Best effort method, meaning we may not be able to return
the FQDN depending on the underlying system configuration.

@return the fully qualified domain name for this IP address,
or if the operation is not allowed by the security check,
the textual representation of the IP address.
jraft-rheakv/rheakv-core/src/main/java/com/alipay/sofa/jraft/rhea/util/NetUtil.java