This is an enhanced limit conn nginx module with sysguard ability.

##Feature

1. Combined sysguard module from Tengine.
2. Enable to configure in main block.
3. No bad effect on the origin limit conn function.
4. Totally compatible with Nginx.

##Notice

1. Replace ngx_http_limit_conn_module with ngx_http_enhanced_limit_conn_module directly.
2. Without sysguard on, this module will act the same as ngx_http_limit_conn_module.
3. With sysguard on, this module will limit connections unless this system running nginx is overload.

##Configuration

limit_conn_zone $binary_remote_addr zone=addr:10m;
limit_conn addr 50;

sysguard on;
sysguard_load load=8;
sysguard_mem swapratio=20%;
sysguard_mem free=100M;

##Directives

###limit_conn_zone 同limit_conn模块一致

###limit_conn 同limit_conn模块一致

###sysguard syntax: sysguard on | off

default: sysguard on

context: http, server, location, location if

开始系统状态监控功能，当超过所设置的阀值，则将limit_conn的限制连接数减半，以应对HTTP DOS攻击。

###sysguard_load syntax: sysguard_load load=[0-10];

default: sysguard_load load=8

context: http, server, location, location if

设置系统CPU负载阀值

###sysguard_mem syntax: sysguard_mem swapratio=[0-100]%; sysguard_mem free=[0-1000]M;

default: sysguard_mem swapratio=20%; sysguard_mem free=100M;

context: http, server, location, location if

设置系统内存阀值

##Contact me Email: hnlq.sysu@gmail.com