If outputs.conf is already configured for auto-load balancing, why not just use one of the supported load balancing methods? You can have Splunk alternate IP addresses for a FQDN by simply configuring multiple A records for the FQDN on the DNS server. You can use autoLBFrequency to determine how often Splunk will rotate servers.
Here's a verbose description of what your forwarder can do and how to configure it:
http://www.splunk.com/base/Documentation/4.1.7/Admin/Setuploadbalancing
Your method seems difficult to support and maintain in the long run. Generally speaking, when an application opens a socket using a hostname, a resolver will attempt various methods to translate the name into an IP address. The resolver is not part of the application, but a part of the IP stack and/or OS. If resolution was provided by a DNS server, there will be an associated TTL for the DNS entry. The TTL specifies that any resolver needs to cache the DNS entry for a specified maximum period of time. This doesn't just affect the client asking for the resolution -- it is also cached by the DNS server answering the question. Unless you use a single DNS server that is also authoritative for the zone, there is no reliable method to predict when a client will actually receive an updated DNS entry, since any intermediary DNS servers will also need to expire their cache.
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