<?xml version="1.0"?>

<!--
  Copyright (C) Nginx, Inc.
  -->

<!DOCTYPE module SYSTEM "../../../../dtd/module.dtd">

<module name="Module ngx_http_upstream_conf_module"
        link="/en/docs/http/ngx_http_upstream_conf_module.html"
        lang="en"
        rev="3">

<section id="summary">

<para>
The <literal>ngx_http_upstream_conf_module</literal> module
allows configuring upstream server groups on-the-fly
via a simple HTTP interface without the need of restarting nginx.
The
<link doc="ngx_http_upstream_module.xml" id="zone">http</link>
or
<link doc="../stream/ngx_stream_upstream_module.xml" id="zone">stream</link>
server group must reside in the shared memory.
<note>
This module is available as part of our
<commercial_version>commercial subscription</commercial_version>.
</note>
</para>

</section>


<section id="example" name="Example Configuration">

<para>
<example>
upstream backend {
    zone upstream_backend 64k;

    ...
}

server {
    location /upstream_conf {
        <emphasis>upstream_conf</emphasis>;
        allow 127.0.0.1;
        deny all;
    }
}
</example>
</para>

</section>


<section id="directives" name="Directives">

<directive name="upstream_conf">
<syntax/>
<default/>
<context>location</context>

<para>
Turns on the HTTP interface of upstream configuration in the surrounding
location.
Access to this location should be
<link doc="ngx_http_core_module.xml" id="satisfy">limited</link>.
</para>

<para>
Configuration commands can be used to:
<list type="bullet">

<listitem>view the group configuration;</listitem>

<listitem>view, modify, or remove a server;</listitem>

<listitem>add a new server.</listitem>

</list>
<note>
Since addresses in a group are not required to be unique, specific
servers in a group are referenced by their IDs.
IDs are assigned automatically and shown when adding a new server
or viewing the group configuration.
</note>
</para>

<para>
A configuration command consists of parameters passed as request arguments,
for example:
<example>
http://127.0.0.1/upstream_conf?upstream=backend
</example>
</para>

<para>
The following parameters are supported:

<list type="tag" compact="no">

<tag-name>
<literal>stream=</literal></tag-name>
<tag-desc>
Selects a
<link doc="../stream/ngx_stream_upstream_module.xml">stream</link>
upstream server group.
Without this parameter, selects an
<link doc="ngx_http_upstream_module.xml">http</link>
upstream server group.
</tag-desc>

<tag-name>
<literal>upstream=</literal><value>name</value></tag-name>
<tag-desc>
Selects a group to work with.
This parameter is mandatory.
</tag-desc>

<tag-name>
<literal>id=</literal><value>number</value></tag-name>
<tag-desc>
Selects a server for viewing, modifying, or removing.
</tag-desc>

<tag-name>
<literal>remove=</literal></tag-name>
<tag-desc>
Removes a server from the group.
</tag-desc>

<tag-name>
<literal>add=</literal></tag-name>
<tag-desc>
Adds a new server to the group.
</tag-desc>

<tag-name>
<literal>backup=</literal></tag-name>
<tag-desc>
Required to add a backup server.
<note>
Before version 1.7.2, <literal>backup=</literal>
was also required to view, modify, or remove existing backup servers.
</note>
</tag-desc>

<tag-name>
<literal>server=</literal><value>address</value></tag-name>
<tag-desc>
Same as the “<literal>address</literal>” parameter
of the
<link doc="ngx_http_upstream_module.xml" id="server">http</link>
or
<link doc="../stream/ngx_stream_upstream_module.xml" id="server">stream</link>
upstream server.
<para>
When adding a server, it is possible to specify it as a domain name.
In this case, changes of the IP addresses that correspond to a domain name
will be monitored and automatically applied to the upstream
configuration without the need of restarting nginx (1.7.2).
This requires the “<literal>resolver</literal>” directive in the
<link doc="ngx_http_core_module.xml" id="resolver">http</link>
or
<link doc="../stream/ngx_stream_core_module.xml" id="resolver">stream</link>
block.
See also the “<literal>resolve</literal>” parameter
of the
<link doc="ngx_http_upstream_module.xml" id="resolve">http</link>
or
<link doc="../stream/ngx_stream_upstream_module.xml" id="resolve">stream</link>
upstream server.
</para>
</tag-desc>

<tag-name>
<literal>service=</literal><value>name</value></tag-name>
<tag-desc>
Same as the “<literal>service</literal>” parameter
of the
<link doc="ngx_http_upstream_module.xml" id="service">http</link>
or
<link doc="../stream/ngx_stream_upstream_module.xml" id="service">stream</link>
upstream server (1.9.13).
</tag-desc>

<tag-name>
<literal>weight=</literal><value>number</value></tag-name>
<tag-desc>
Same as the “<literal>weight</literal>” parameter
of the
<link doc="ngx_http_upstream_module.xml" id="weight">http</link>
or
<link doc="../stream/ngx_stream_upstream_module.xml" id="weight">stream</link>
upstream server.
</tag-desc>

<tag-name>
<literal>max_conns=</literal><value>number</value></tag-name>
<tag-desc>
Same as the “<literal>max_conns</literal>” parameter
of the
<link doc="ngx_http_upstream_module.xml" id="max_conns">http</link>
or
<link doc="../stream/ngx_stream_upstream_module.xml" id="max_conns">stream</link>
upstream server.
</tag-desc>

<tag-name>
<literal>max_fails=</literal><value>number</value></tag-name>
<tag-desc>
Same as the “<literal>max_fails</literal>” parameter
of the
<link doc="ngx_http_upstream_module.xml" id="max_fails">http</link>
or
<link doc="../stream/ngx_stream_upstream_module.xml" id="max_fails">stream</link>
upstream server.
</tag-desc>

<tag-name>
<literal>fail_timeout=</literal><value>time</value></tag-name>
<tag-desc>
Same as the “<literal>fail_timeout</literal>” parameter
of the
<link doc="ngx_http_upstream_module.xml" id="fail_timeout">http</link>
or
<link doc="../stream/ngx_stream_upstream_module.xml" id="fail_timeout">stream</link>
upstream server.
</tag-desc>

<tag-name>
<literal>slow_start=</literal><value>time</value></tag-name>
<tag-desc>
Same as the “<literal>slow_start</literal>” parameter
of the
<link doc="ngx_http_upstream_module.xml" id="slow_start">http</link>
or
<link doc="../stream/ngx_stream_upstream_module.xml" id="slow_start">stream</link>
upstream server.
</tag-desc>

<tag-name>
<literal>down=</literal></tag-name>
<tag-desc>
Same as the “<literal>down</literal>” parameter
of the
<link doc="ngx_http_upstream_module.xml" id="down">http</link>
or
<link doc="../stream/ngx_stream_upstream_module.xml" id="down">stream</link>
upstream server.
</tag-desc>

<tag-name id="drain"><literal>drain=</literal></tag-name>
<tag-desc>
Puts the
<link doc="ngx_http_upstream_module.xml">http</link>
upstream server in the “draining” mode (1.7.5).
In this mode, only requests of the
<link doc="ngx_http_upstream_module.xml" id="sticky">bound</link> to the server
will be proxied to it.
</tag-desc>

<tag-name>
<literal>up=</literal></tag-name>
<tag-desc>
The opposite of the “<literal>down</literal>” parameter
of the
<link doc="ngx_http_upstream_module.xml" id="down">http</link>
or
<link doc="../stream/ngx_stream_upstream_module.xml" id="down">stream</link>
upstream server.
</tag-desc>

<tag-name>
<literal>route=</literal><value>string</value></tag-name>
<tag-desc>
Same as the “<literal>route</literal>” parameter of the
<link doc="ngx_http_upstream_module.xml" id="route">http</link>
upstream server.
</tag-desc>

</list>

The first three parameters select an object.
This can be either the whole http or stream upstream server group,
or a specific server.
Without other parameters, the configuration of the selected
group or server is shown.
</para>

<para>
For example, to view the configuration of the whole group, send:
<example>
http://127.0.0.1/upstream_conf?upstream=backend
</example>

To view the configuration of a specific server, also specify its ID:
<example>
http://127.0.0.1/upstream_conf?upstream=backend&amp;id=42
</example>
</para>

<para>
To add a new server,
specify its address in the “<literal>server=</literal>” parameter.
Without other parameters specified, a server will be added with other
parameters set to their default values (see the
<link doc="ngx_http_upstream_module.xml" id="server">http</link>
or
<link doc="../stream/ngx_stream_upstream_module.xml" id="server">stream</link>
“<literal>server</literal>” directive).
</para>

<para>
For example, to add a new primary server, send:
<example>
http://127.0.0.1/upstream_conf?add=&amp;upstream=backend&amp;server=127.0.0.1:8080
</example>

To add a new backup server, send:
<example>
http://127.0.0.1/upstream_conf?add=&amp;upstream=backend&amp;backup=&amp;server=127.0.0.1:8080
</example>

To add a new primary server,
set its parameters to non-default values
and mark it as “<literal>down</literal>”, send:
<example>
http://127.0.0.1/upstream_conf?add=&amp;upstream=backend&amp;server=127.0.0.1:8080&amp;weight=2&amp;down=
</example>

To remove a server, specify its ID:
<example>
http://127.0.0.1/upstream_conf?remove=&amp;upstream=backend&amp;id=42
</example>

To mark an existing server as “<literal>down</literal>”, send:
<example>
http://127.0.0.1/upstream_conf?upstream=backend&amp;id=42&amp;down=
</example>

To modify the address of an existing server, send:
<example>
http://127.0.0.1/upstream_conf?upstream=backend&amp;id=42&amp;server=192.0.2.3:8123
</example>

To modify other parameters of an existing server, send:
<example>
http://127.0.0.1/upstream_conf?upstream=backend&amp;id=42&amp;max_fails=3&amp;weight=4
</example>

The above examples are for an
<link doc="ngx_http_upstream_module.xml">http</link>
upstream server group.
Similar examples for a
<link doc="../stream/ngx_stream_upstream_module.xml">stream</link>
upstream server group require the “<literal>stream=</literal>” parameter.
</para>

</directive>

</section>

</module>