---
title: Weave Proxy
layout: default
---

# Proxy

The weave proxy automatically attaches containers to the weave network
that have been started using the ordinary Docker command-line
interface or Docker remote API.

Using the proxy brings some additional benefits over `weave run`. The
proxy ensures that the weave network interface is available before
starting a container's application process. Furthermore, containers
can be started in foreground mode, and can be automatically removed
(with the ususal `--rm`).

## Setup

To do this, while still connecting containers to the weave network,
you can use the weave proxy. We can start the proxy with

    host1$ weave launch-proxy

By default, the proxy will connect to docker at
`unix:///var/run/docker.sock`, and listen on port 12375. However, we
can adjust the connection to docker via the `-H` argument. All docker
commands can be run via the proxy, so it is safe to globally adjust
your `DOCKER_HOST`.

    host1$ export DOCKER_HOST=tcp://host1:12375
    host1$ docker ps

## Usage

When containers are created via the weave proxy, their entrypoint will
be modified to wait for the weave network interface to become
available. When they are started via the weave proxy, any IP addresses
and networks specified in the `WEAVE_CIDR` environment variable will
be attached. We can create and start a container via the weave proxy
with

    host1$ docker run -e WEAVE_CIDR=10.2.1.1/24 -ti ubuntu /bin/sh

or, equivalently with

    host1$ docker create -e WEAVE_CIDR=10.2.1.1/24 -ti ubuntu /bin/sh
    5ef831df61d50a1a49272357155a976595e7268e590f0a2c75693337b14e1382
    host1$ docker start 5ef831df61d50a1a49272357155a976595e7268e590f0a2c75693337b14e1382

Multiple IP addresses and networks can be supplied in the WEAVE_CIDR
variable by space-separating them, as in
`WEAVE_CIDR=10.2.1.1/24 10.2.2.1/24`.

## Usage with WeaveDNS

Containers started via the proxy can be automatically configured to
use WeaveDNS for name resolution. To accomplish this we need to launch
the proxy with the `--with-dns` option

    host1$ weave launch
    host1$ weave launch-dns 10.2.254.1/24
    host1$ weave launch-proxy --with-dns

With this done, any containers launched through the proxy will use
weaveDNS for name resolution. WeaveDNS is used in addition to any dns
servers specified via the `--dns` option. More details on weaveDNS can
be found in the [weaveDNS documentation](weavedns.html).

## Usage with IPAM

To automatically assign a unique IP address to a container, weave must
be told on startup what range of addresses to allocate from. For
example:

    host1# weave launch -iprange 10.2.3.0/24
    host1$ weave launch-proxy
    host1$ export DOCKER_HOST=tcp://host1:12375

With this done, we can automatically assign an address to a container
by providing a blank `WEAVE_CIDR` value, as in

    host1$ docker run -e WEAVE_CIDR= -ti ubuntu /bin/sh

Alternatively, to enable automatic allocation of all containers
without a `WEAVE_CIDR`, we can launch the proxy with the `--with-ipam`
option. For example:

    host1$ weave launch-proxy --with-ipam

More details on IPAM can be found in the [IPAM documentation](ipam.html).

## Limitations

* The proxy does not currently support TLS.
* If you have a firewall, you will need to make sure port 12375 is open.