=encoding utf-8

=head1 NAME

ngx_http_upstream_conf_module - Module ngx_http_upstream_conf_module




=head1



The C<ngx_http_upstream_conf_module> module
allows configuring upstream server groups on-the-fly
via a simple HTTP interface without the need of restarting nginx.
The
L<http|ngx_http_upstream_module>
or
L<stream|ngx_stream_upstream_module>
server group must reside in the shared memory.

B<NOTE>

This module is available as part of our
commercial subscription.





=head1 Example Configuration




    
    upstream backend {
        zone upstream_backend 64k;
    
        ...
    }
    
    server {
        location /upstream_conf {
            <emphasis>upstream_conf</emphasis>;
            allow 127.0.0.1;
            deny all;
        }
    }






=head1 Directives

=head2 upstream_conf




B<context:> I<location>





Turns on the HTTP interface of upstream configuration in the surrounding
location.
Access to this location should be
L<limited|ngx_http_core_module>.





Configuration commands can be used to:

=over




=item *
view the group configuration;


=item *
view, modify, or remove a server;


=item *
add a new server.


=back



B<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.






A configuration command consists of parameters passed as request arguments,
for example:

    
    http://127.0.0.1/upstream_conf?upstream=backend







The following parameters are supported:


=over



=item 
C<stream=>




Selects a
L<stream|ngx_stream_upstream_module>
upstream server group.
Without this parameter, selects an
L<http|ngx_http_upstream_module>
upstream server group.



=item 
C<upstream=>I<C<name>>




Selects a group to work with.
This parameter is mandatory.



=item 
C<id=>I<C<number>>




Selects a server for viewing, modifying, or removing.



=item 
C<remove=>




Removes a server from the group.



=item 
C<add=>




Adds a new server to the group.



=item 
C<backup=>




Required to add a backup server.

B<NOTE>

Before version 1.7.2, C<backup=>
was also required to view, modify, or remove existing backup servers.




=item 
C<server=>I<C<address>>




Same as the “C<address>” parameter
of the
L<http|ngx_http_upstream_module>
or
L<stream|ngx_stream_upstream_module>
upstream server.


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 “C<resolver>” directive in the
L<http|ngx_http_core_module>
or
L<stream|ngx_stream_core_module>
block.
See also the “C<resolve>” parameter
of the
L<http|ngx_http_upstream_module>
or
L<stream|ngx_stream_upstream_module>
upstream server.





=item 
C<service=>I<C<name>>




Same as the “C<service>” parameter
of the
L<http|ngx_http_upstream_module>
or
L<stream|ngx_stream_upstream_module>
upstream server (1.9.13).



=item 
C<weight=>I<C<number>>




Same as the “C<weight>” parameter
of the
L<http|ngx_http_upstream_module>
or
L<stream|ngx_stream_upstream_module>
upstream server.



=item 
C<max_conns=>I<C<number>>




Same as the “C<max_conns>” parameter
of the
L<http|ngx_http_upstream_module>
or
L<stream|ngx_stream_upstream_module>
upstream server.



=item 
C<max_fails=>I<C<number>>




Same as the “C<max_fails>” parameter
of the
L<http|ngx_http_upstream_module>
or
L<stream|ngx_stream_upstream_module>
upstream server.



=item 
C<fail_timeout=>I<C<time>>




Same as the “C<fail_timeout>” parameter
of the
L<http|ngx_http_upstream_module>
or
L<stream|ngx_stream_upstream_module>
upstream server.



=item 
C<slow_start=>I<C<time>>




Same as the “C<slow_start>” parameter
of the
L<http|ngx_http_upstream_module>
or
L<stream|ngx_stream_upstream_module>
upstream server.



=item 
C<down=>




Same as the “C<down>” parameter
of the
L<http|ngx_http_upstream_module>
or
L<stream|ngx_stream_upstream_module>
upstream server.



=item C<drain=>




Puts the
L<http|ngx_http_upstream_module>
upstream server into the “draining” mode (1.7.5).
In this mode, only requests
L<bound|ngx_http_upstream_module> to the server
will be proxied to it.



=item 
C<up=>




The opposite of the “C<down>” parameter
of the
L<http|ngx_http_upstream_module>
or
L<stream|ngx_stream_upstream_module>
upstream server.



=item 
C<route=>I<C<string>>




Same as the “C<route>” parameter of the
L<http|ngx_http_upstream_module>
upstream server.




=back



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.





For example, to view the configuration of the whole group, send:

    
    http://127.0.0.1/upstream_conf?upstream=backend



To view the configuration of a specific server, also specify its ID:

    
    http://127.0.0.1/upstream_conf?upstream=backend&id=42







To add a new server,
specify its address in the “C<server=>” parameter.
Without other parameters specified, a server will be added with other
parameters set to their default values (see the
L<http|ngx_http_upstream_module>
or
L<stream|ngx_stream_upstream_module>
“C<server>” directive).





For example, to add a new primary server, send:

    
    http://127.0.0.1/upstream_conf?add=&upstream=backend&server=127.0.0.1:8080



To add a new backup server, send:

    
    http://127.0.0.1/upstream_conf?add=&upstream=backend&backup=&server=127.0.0.1:8080



To add a new primary server,
set its parameters to non-default values
and mark it as “C<down>”, send:

    
    http://127.0.0.1/upstream_conf?add=&upstream=backend&server=127.0.0.1:8080&weight=2&down=



To remove a server, specify its ID:

    
    http://127.0.0.1/upstream_conf?remove=&upstream=backend&id=42



To mark an existing server as “C<down>”, send:

    
    http://127.0.0.1/upstream_conf?upstream=backend&id=42&down=



To modify the address of an existing server, send:

    
    http://127.0.0.1/upstream_conf?upstream=backend&id=42&server=192.0.2.3:8123



To modify other parameters of an existing server, send:

    
    http://127.0.0.1/upstream_conf?upstream=backend&id=42&max_fails=3&weight=4



The above examples are for an
L<http|ngx_http_upstream_module>
upstream server group.
Similar examples for a
L<stream|ngx_stream_upstream_module>
upstream server group require the “C<stream=>” parameter.