These Cherokee modules allow to balance the load among several servers. Cherokee is completely modular, and thus a distinction must be made clear.
Balancer modules only implement the balancing strategy. To actually use one of these strategies you will need to select a handler that makes use of balancers in the cherokee-admin interface. Besides this, balancing strategies can be utilized both directly within first level Cherokee handlers and as second level subsystems used by other first level handlers. The Generic balancer handler is an example of the former, while the latter would be the case for the FastCGI or SCGI handlers that can offer load balancing as well.
These handlers can be chosen within the Handler tab of the Rule Options section.
When a specific balancing strategy is selected, there are two possible settings as information sources:
Remote: Cherokee will simply dispatch the request to the specified host. As many hosts as needed can be added, and Cherokee will simply apply the balancing strategy among them. If for any reason the requests made to these hosts could not be performed, the processes would simply fail.
Local: As before, many hosts can be specified (despite the name, the selection is not limited to the localhost). This works the same way as the previous option. But in this case, if a request cannot be responded then instead of failing directly a specified command would be launched before reconnecting to try again. Te most common use of this would be launching the service that should handle the request, but it is a flexible mechanism that in theory could allow you to reroute the information to allo you to serve SSH sessions via your webserver or any other neat tricks you can think about.
Note that because of Cherokee's flexibility and modularity, sometimes and deppending of the situation one or the other setting might not make much sense. In such ocasions cherokee-admin will simply hide whatever options do not apply.
This is the list of currently supported balancing strategies:
And these are the handlers that use balancing: