Nginx http proxy support for backend server health checks / status monitoring url

[Detlef_R]

Hello,

I’m using nginx as a http proxy / loadbalancer for an application which
which has the following setup on the backend servers:

• https/403 provides the application at:

  • https://hostname-of-backend/app/

• status monitoring url is available at:

  • http://hostname-of-backend/foo/server_status
  • https://hostname-of-backend/foo/server_status

So the status url is available over both http and https, and the status
url tells if the application is fully up and running or not.
Actual application is only available over https.

It’s important to decide the backend server availability based on the
status url contents/reply,
otherwise you might push traffic to a backend that isn’t fully up and
running yet,
causing false errors to end users.

So… I don’t think nginx currently provides proper status monitoring url
support for proxy backends ?

I’ve found some plugins for this, but they seem to have limitations
aswell:

• HTTP Healthcheck | NGINX

  • GitHub - cep21/healthcheck_nginx_upstreams: Health checks upstreams for nginx
  • only http 1.0 support, no http 1.1 support
  • doesn’t seem to be maintained anymore, latest version 2+ years old

• GitHub - yaoweibin/nginx_upstream_check_module: Health checks upstreams for nginx

  • only supports http backends, so health checks must be over http
    aswell, not over https
  • if actual app is on 443/https, cannot configure separate port 80
    for health checks over http
  • only “ssl” health check possible for https backends

Any suggestions? Or should I start hacking and improving the existing
plugins…
Thanks!

– Pasi

[SSPasi_KS_rkkS_inen]

On Thu, Oct 31, 2013 at 02:26:41PM +0200, Pasi K. wrote:

• https://hostname-of-backend/foo/server_status
  I’ve found some plugins for this, but they seem to have limitations aswell:

Any suggestions? Or should I start hacking and improving the existing plugins…
Thanks!

This functionality is currently available in our commercial version:

NGINX Application Platform | NGINX

The documentation is here:
http://nginx.org/en/docs/http/ngx_http_upstream_module.html#health_check

[SSPasi_KS_rkkS_inen]

HPPS health check is difficult for the check module, I have added an
alternative feature for this request. The ‘port’ option can be
specifed with different port from the server’s original port. For
example:

server {
server 192.168.1.1:443;

 check interval=3000 rise=1 fall=3 timeout=2000 type=http port=80;
 check_http_send "GET / HTTP/1.0\r\n\r\n";
 check_http_expect_alive http_2xx http_3xx;

}

This feature has been exeisted in the develop branch for upstream
check module:
(GitHub - yaoweibin/nginx_upstream_check_module at development)
Or tengine: ngx_http_upstream_check_module - The Tengine Web Server

2013/10/31 Ruslan E. [email protected]:

  - http://hostname-of-backend/foo/server_status

          - only "ssl" health check possible for https backends

---

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–
Weibin Y.
Developer @ Server Platform Team of Taobao

[SSPasi_KS_rkkS_inen]

On Fri, Nov 01, 2013 at 01:58:52PM +0800, Weibin Y. wrote:

 check_http_expect_alive http_2xx http_3xx;

}

This feature has been exeisted in the develop branch for upstream
check module:
(GitHub - yaoweibin/nginx_upstream_check_module at development)
Or tengine: ngx_http_upstream_check_module - The Tengine Web Server

Great! Exactly what I need…

I’ll test it soon.

– Pasi