Httpd ProxyPass

External

• https://httpd.apache.org/docs/current/mod/mod_proxy.html#proxypass

Internal

• httpd Directives
• mod_proxy Concepts
• ProxyPassMatch
• ProxyPassReverse

Overview

The ProxyPass directive maps remote servers into the local server URL-space, by creating a worker that handles the request associated with the declared remote URL. A more flexible alternative is the use of RewriteRule with the [P] flag.

For ProxyPass-related mod_proxy concepts see:

ProxyPass Concepts

It can be used inside a <Location> or <LocationMatch> directive, see Example below. <ProxyPass> is not supported within <Directory> and <Files> containers.

Syntax

ProxyPass [path] !|url [key=value ...]

The path is the name of a local virtual path.

The url is a partial URL for the origin server. It cannot include a query string.

If path ends with a trailing "/", the url should also end with a trailing "/", and vice-versa, otherwise the resulting requests to the backend may miss some of the needed slashes and produce unwanted results.

Example

ProxyPass "/something" "http://example.com/something-else

Alternative using <Location>:

<Location "/something">
    ProxyPass "http://example.com/something-else"
</Location>

Order

ProxyPass and ProxyPassMatch rules are checked in the order in which they were specified in the configuration file, and the first rule match wins. For the same reason, exclusions must come before the general ProxyPass directives.

Also see:

Worker Sharing

Preventing a Sub-Directory to Be Proxied

ProxyPass "/something/do-not-proxy" "!"
ProxyPass "/something" "http://example.com"

Connection Pool Configuration

Configuration example:

ProxyPass "/something" "httpd://backend.example.com" max=20 ttl=120 retry=300

For concepts, see:

ProxyPass Connection Pool Concepts

All the parameters described below apply to BalancerMember configuration as well. BalancerMember has a few special parameters that are described here: BalancerMember Configuration Reference.

max

Reduces the maximum number of connections in the pool, to the specified value, as described in mod_proxy Concepts - Connection Pooling.

ttl

The time to live in seconds after which an inactive connection in the pool is closed. mod_proxy connection pool dynamics is explained here: mod_proxy Concepts - Connection Pooling. There is no default, which means that by default connections won't expire. ttl can be used to avoid using a connection which is subject to closing because of the backend server's keep-alive timeout.

timeout

The number of seconds httpd waits for data to be sent by the backend before it timeouts. If not specified, the default is given by ProxyTimeout. mod_proxy connection pool dynamics is explained here: mod_proxy Concepts - Connection Pooling

acquire

The number of milliseconds to wait for a connection to become free in the pool. There is no default. mod_proxy connection pool dynamics is explained here: mod_proxy Concepts - Connection Pooling