Apache Module mod_heartbeat
| Description: | Sends messages with server status to frontend proxy |
|---|---|
| Status: | Experimental |
| ModuleIdentifier: | heartbeat_module |
| SourceFile: | mod_heartbeat |
| Compatibility: | Available in Apache 2.3 and later |
Summary
mod_heartbeat sends multicast messages to a mod_heartmonitor listener that advertises the servers current connection count. Usually, mod_heartmonitor will be running on a proxy server with mod_lbmethod_heartbeat loaded, which allows ProxyPass to use the "heartbeat" lbmethod inside of ProxyPass.
mod_heartbeat itself is loaded on the origin server(s) that serve requests through the proxy server(s).
mod_heartbeat, mod_status and mod_watchdog must be either a static modules or, if a dynamic module, must be loaded before mod_heartbeat. Consuming mod_heartbeat Output
Every 1 second, this module generates a single multicast UDP packet, containing the number of busy and idle workers. The packet is a simple ASCII format, similar to GET query parameters in HTTP.
An Example Packet
v=1&ready=75&busy=0
Consumers should handle new variables besides busy and ready, separated by '&', being added in the future.
HeartbeatAddress Directive
| Description: | Multicast address for heartbeat packets |
|---|---|
| Syntax: | HeartbeatAddress addr:port |
| Default: | disabled |
| Context: | server config |
| Status: | Experimental |
| Module: | mod_heartbeat |
The HeartbeatAddress directive specifies the multicast address to which mod_heartbeat will send status information. This address will usually correspond to a configured HeartbeatListen on a frontend proxy system.
HeartbeatAddress 239.0.0.1:27999
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