upstream-server
There are 3 repositories under upstream-server topic.
zhouchangxun/ngx_stream_upstream_check_module
nginx health checker (tcp/udp/http) for stream upstream servers.
sysulq/nginx_upstream_check_module
(Not maintained) This module can be used in pure nginx-1.4.7 and nginx-1.6.2 to check upstream servers, with several patches applied.