mod_proxy_cluster 2.0
An inteligent load-balancer for Apache httpd
No Matches

Project mod_cluster is a httpd-based load-balancer. It uses a communication channel to forward requests from httpd to one of a set of application server nodes. Unlike mod_jk and mod_proxy, mod_cluster leverages an additional connection between the application server nodes and httpd to transmit server-side load-balance factors and lifecycle events back to httpd. This additional feedback channel allows mod_cluster to offer a level of intelligence and granularity not found in other load-balancing solutions.

Mod_cluster boasts the following advantages over other httpd-based load-balancers:

  • Dynamic configuration of httpd workers
  • Server-side load balance factor calculation
  • Fine grained web-app lifecycle control
  • AJP is optional

Project Structure

native (native httpd modules)

Reverse Proxy (httpd) Modules

To build the native component from the sources you need a C compiler and the following tools:

  • m4
  • perl
  • autoconf
  • automake
  • libtool
  • make
  • patch
  • python


The codebase follows certain code style that is specified in .clang-format file within the native directory. You can run the tool manually from the mentioned directory by executing clang-format -n <file>. To apply all suggestions to a file automatically, run clang-format -i <file>.

However, there are some cases where breaking the code style may result in better clarity. In those cases enclose the corresponding part of code like this

/* clang-format off */
/* clang-format on */

The style check will ignore everything between the two comments. (Please, don't abuse it.)


The project contains some tests too. You can find them with a separate README in the test subdirectory.


This software is distributed under the terms of the GNU Lesser General Public License (see lgpl.txt).