= Name =

'''nginx_http_upstream_check_module''' - support upstream health check with Nginx

= Synopsis =

<geshi lang="nginx">

http {

    upstream cluster {

        # simple round-robin
        server 192.168.0.1:80;
        server 192.168.0.2:80;

        check interval=5000 rise=1 fall=3 timeout=4000;

        #check interval=3000 rise=2 fall=5 timeout=1000 type=ssl_hello;

        #check interval=3000 rise=2 fall=5 timeout=1000 type=http;
        #check_http_send "HEAD / HTTP/1.0\r\n\r\n";
        #check_http_expect_alive http_2xx http_3xx;
    }

    server {
        listen 80;

        location / {
            proxy_pass http://cluster;
        }

        location /status {
            check_status;

            access_log   off;
            allow SOME.IP.ADD.RESS;
            deny all;
       }
    }

}
</geshi>

= Description =

Add the support of health check with the upstream servers.

= Directives =

== check ==

'''syntax:''' ''check interval=milliseconds [fall=count] [rise=count] [timeout=milliseconds] [default_down=true|false] [type=tcp|http|ssl_hello|mysql|ajp|fastcgi]''

'''default:''' ''none, if parameters omitted, default parameters are interval=30000 fall=5 rise=2 timeout=1000 default_down=true type=tcp''

'''context:''' ''upstream''

'''description:''' Add the health check for the upstream servers.

The parameters' meanings are:

* ''interval'': the check request's interval time.
* ''fall''(fall_count): After fall_count check failures, the server is marked down.
* ''rise''(rise_count): After rise_count check success, the server is marked up.
* ''timeout'': the check request's timeout.
* ''default_down'': set initial state of backend server, default is down.
* ''port'': specify the check port in the backend servers. It can be different with the original servers port. Default the port is 0 and it means the same as the original backend server.
* ''type'': the check protocol type:
# ''tcp'' is a simple tcp socket connect and peek one byte.
# ''ssl_hello'' sends a client ssl hello packet and receives the server ssl hello packet.
# ''http'' sends a http request packet, receives and parses the http response to diagnose if the upstream server is alive.
# ''mysql'' connects to the mysql server, receives the greeting response to diagnose if the upstream server is alive.
# ''ajp'' sends a AJP Cping packet, receives and parses the AJP Cpong response to diagnose if the upstream server is alive.
# ''fastcgi'' send a fastcgi request, receives and parses the fastcgi response to diagnose if the upstream server is alive.

== check_http_send ==

'''syntax:''' ''check_http_send http_packet''

'''default:''' ''"GET / HTTP/1.0\r\n\r\n"''

'''context:''' ''upstream''

'''description:''' If you set the check type is http, then the check function will sends this http packet to check the upstream server.

== check_http_expect_alive ==

'''syntax:''' ''check_http_expect_alive [ http_2xx | http_3xx | http_4xx | http_5xx ]''

'''default:''' ''http_2xx | http_3xx''

'''context:''' ''upstream''

'''description:''' These status codes indicate the upstream server's http response is ok, the backend is alive.

== check_keepalive_requests ==

'''syntax:''' ''check_keepalive_requests num''

'''default:''' ''check_keepalive_requests 1''

'''context:''' ''upstream''

'''description:''' The directive specifies the number of requests sent on a connection, the default vaule 1 indicates that nginx will certainly close the connection after a request.

== check_fastcgi_param ==

'''Syntax:''' ''check_fastcgi_params parameter value''

'''default:''' see below

'''context:''' ''upstream''

'''description:''' If you set the check type is fastcgi, then the check function will sends this fastcgi headers to check the upstream server. The default directive looks like:

<geshi lang="nginx">
      check_fastcgi_param "REQUEST_METHOD" "GET";
      check_fastcgi_param "REQUEST_URI" "/";
      check_fastcgi_param "SCRIPT_FILENAME" "index.php";
</geshi>

== check_shm_size ==

'''syntax:''' ''check_shm_size size''

'''default:''' ''1M''

'''context:''' ''http''

'''description:''' Default size is one megabytes. If you check thousands of servers, the shared memory for health check may be not enough, you can enlarge it with this directive.

== check_status ==

'''syntax:''' ''check_status [html|csv|json]''

'''default:''' ''none''

'''context:''' ''location''

'''description:''' Display the health checking servers' status by HTTP. This directive should be set in the http block.

You can specify the default display format. The formats can be `html`, `csv` or `json`. The default type is `html`. It also supports to specify the format by the request argument. Suppose your `check_status` location is '/status', the argument of `format` can change the display page's format. You can do like this:

<geshi lang="bash">
    /status?format=html
    /status?format=csv
    /status?format=json
</geshi>

At present, you can fetch the list of servers with the same status by the argument of `status`. For example:

<geshi lang="bash">
    /status?format=html&status=down
    /status?format=csv&status=up
</geshi>

Below it's the sample html page:

<geshi lang="bash">
    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
    <html xmlns="http://www.w3.org/1999/xhtml">
    <head>
    <title>Nginx http upstream check status</title>
    </head>
    <body>
        <h1>Nginx http upstream check status</h1>
        <h2>Check upstream server number: 1, generation: 3</h2>
        <table style="background-color:white" cellspacing="0"        cellpadding="3" border="1">
            <tr bgcolor="#C0C0C0">
                <th>Index</th>
                <th>Upstream</th>
                <th>Name</th>
                <th>Status</th>
                <th>Rise counts</th>
                <th>Fall counts</th>
                <th>Check type</th>
                <th>Check port</th>
            </tr>
            <tr>
                <td>0</td>
                <td>backend</td>
                <td>106.187.48.116:80</td>
                <td>up</td>
                <td>39</td>
                <td>0</td>
                <td>http</td>
                <td>80</td>
            </tr>
        </table>
    </body>
    </html>

Below it's the sample of csv page:

<geshi lang="bash">
    0,backend,106.187.48.116:80,up,46,0,http,80
</geshi>

Below it's the sample of json page:

<geshi lang="bash">
    {"servers": {
      "total": 1,
      "generation": 3,
      "server": [
       {"index": 0, "upstream": "backend", "name": "106.187.48.116:80", "status": "up", "rise": 58, "fall": 0, "type": "http", "port": 80}
      ]
     }}
</geshi>


= Installation =

Download the latest version of the release tarball of this module from [http://github.com/yaoweibin/nginx_upstream_check_module github]

Grab the nginx source code from [http://nginx.org/ nginx.org], for example, the version 1.0.14 (see nginx compatibility), and then build the source with this module:

<geshi lang="bash">
    $ wget 'http://nginx.org/download/nginx-1.0.14.tar.gz'
    $ tar -xzvf nginx-1.0.14.tar.gz
    $ cd nginx-1.0.14/
    $ patch -p1 < /path/to/nginx_http_upstream_check_module/check.patch

    $ ./configure --add-module=/path/to/nginx_http_upstream_check_module

    $ make
    $ make install
</geshi>

= Note =

If you use nginx-1.2.1 or nginx-1.3.0, the nginx upstream round robin module changed greatly. You should use the patch named 'check_1.2.1.patch'.

If you use nginx-1.2.2+ or nginx-1.3.1+, It added the upstream least_conn module. You should use the patch named 'check_1.2.2+.patch'.

If you use nginx-1.2.6+ or nginx-1.3.9+, It adjusted the round robin module. You should use the patch named 'check_1.2.6+.patch'.

If you use nginx-1.5.12+, You should use the patch named 'check_1.5.12+.patch'.

If you use nginx-1.7.2+, You should use the patch named 'check_1.7.2+.patch'.

The patch just adds the support for the official Round-Robin, Ip_hash and least_conn upstream module. But it's easy to expand my module to other upstream modules. See the patch for detail.

If you want to add the support for upstream fair module, you can do it like this:

<geshi lang="bash">
    $ git clone git://github.com/gnosek/nginx-upstream-fair.git
    $ cd nginx-upstream-fair
    $ patch -p2 < /path/to/nginx_http_upstream_check_module/upstream_fair.patch
    $ cd /path/to/nginx-1.0.14
    $ ./configure --add-module=/path/to/nginx_http_upstream_check_module --add-module=/path/to/nginx-upstream-fair-module
    $ make
    $ make install
</geshi>

If you want to add the support for nginx sticky module, you can do it like this:

<geshi lang="bash">
    $ svn checkout http://nginx-sticky-module.googlecode.com/svn/trunk/ nginx-sticky-module
    $ cd nginx-sticky-module
    $ patch -p0 < /path/to/nginx_http_upstream_check_module/nginx-sticky-module.patch
    $ cd /path/to/nginx-1.0.14
    $ ./configure --add-module=/path/to/nginx_http_upstream_check_module --add-module=/path/to/nginx-sticky-module
    $ make
    $ make install
</geshi>

Note that, the nginx-sticky-module also needs the original check.patch.


= Compatibility =

* The module version 0.1.5 should be compatibility with 0.7.67+
* The module version 0.1.8 should be compatibility with Nginx-1.0.14+

= Notes =

= TODO =

= Known Issues =

= Changelogs =

== v0.3 ==
* support keepalive check requests
* fastcgi check requests
* json/csv check status page support

== v0.1 ==
* first release

= Authors =

Weibin Yao(姚伟斌) ''yaoweibin at gmail dot com''

Matthieu Tourne


= Copyright & License =

This README template copy from [http://github.com/agentzh agentzh].

The health check part is borrowed the design of Jack Lindamood's healthcheck module [http://github.com/cep21/healthcheck_nginx_upstreams healthcheck_nginx_upstreams];

This module is licensed under the BSD license.

Copyright (C) 2014 by Weibin Yao <yaoweibin@gmail.com>

Copyright (C) 2010-2014 Alibaba Group Holding Limited

Copyright (C) 2014 by LiangBin Li

Copyright (C) 2014 by Zhuo Yuan

Copyright (C) 2012 by Matthieu Tourne

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

