When working with Apache 2.4's proxy balancing functionality, you might encounter this critical error during server startup:

[proxy:crit] [pid 11868] AH02432: Cannot find LB Method: byrequests
[proxy_balancer:emerg] [pid 11868] (22)Invalid argument: AH01183: Cannot share balancer

This occurs when Apache can't locate the required load balancing method modules, specifically when trying to use lbmethod_byrequest.

For proxy balancing to work properly in Apache 2.4, you need several modules:

mod_proxy
mod_proxy_balancer
mod_lbmethod_byrequests (or other lbmethod modules)

The key missing piece in most cases is the mod_lbmethod_byrequests module which implements the actual balancing algorithm.

When building Apache from source with static modules, you must explicitly include the load balancing method modules:

./configure \
--enable-proxy \
--enable-proxy-balancer \
--enable-lbmethod-byrequests \
--enable-lbmethod-bytraffic \
--enable-lbmethod-bybusyness \
--with-mpm=prefork

If you've already compiled Apache without these modules, you'll need to:

1. Run make clean
2. Reconfigure with the proper modules
3. Recompile and reinstall

After successful compilation, verify the modules are available:

httpd -M | grep lbmethod

You should see output similar to:

lbmethod_byrequests (shared)
lbmethod_bytraffic (shared)
lbmethod_bybusyness (shared)

Here's a working example of a proxy balancer configuration using byrequests method:

    BalancerMember http://192.168.1.101:8080
    BalancerMember http://192.168.1.102:8080
    ProxySet lbmethod=byrequests


ProxyPass "/app" "balancer://mycluster"
ProxyPassReverse "/app" "balancer://mycluster"

• Check your Apache error logs for exact module loading sequence
• Verify module files exist in your modules directory
• Ensure no typos in LoadModule directives
• Check for version mismatches between modules and Apache core

If you can't recompile Apache, consider:

1. Using dynamic modules instead:

LoadModule lbmethod_byrequest_module modules/mod_lbmethod_byrequest.so

2. Using a different load balancing method that's available
3. Implementing balancing at a different layer (HAProxy, Nginx)

When compiling Apache 2.4 with static modules, many developers encounter the frustrating proxy balancer error where the system fails to recognize the byrequests load balancing method. The key symptoms are:

[proxy:crit] [pid 11868] AH02432: Cannot find LB Method: byrequests
[proxy_balancer:emerg] [pid 11868] (22)Invalid argument: AH01183: Cannot share balancer

This occurs because the mod_lbmethod_byrequests module isn't properly compiled into the Apache binary.

The solution requires compiling Apache with both the proxy modules AND the load balancing method modules. Here's the complete set of required flags:

./configure \
--enable-proxy \
--enable-proxy-balancer \
--enable-proxy-http \
--enable-lbmethod-byrequests \
--enable-lbmethod-bytraffic \
--enable-lbmethod-bybusyness \
--enable-slotmem-shm

After successful compilation, verify the modules are loaded:

./bin/apachectl -M | grep lbmethod
lbmethod_byrequests (shared)
lbmethod_bytraffic (shared)
lbmethod_bybusyness (shared)

Here's a working proxy balancer configuration that should work after proper compilation:

<Proxy balancer://mycluster>
    BalancerMember http://192.168.1.101:8080 route=node1
    BalancerMember http://192.168.1.102:8080 route=node2
    ProxySet lbmethod=byrequests
</Proxy>

ProxyPass "/app" "balancer://mycluster"
ProxyPassReverse "/app" "balancer://mycluster"

If issues persist:

• Run make clean before recompiling
• Verify OpenSSL version compatibility
• Check for conflicting modules in your configuration
• Test with minimal configuration first