weave/site/proxy.md

title, layout

title	layout
Weave Proxy	default

Proxy

Instead of the weave command-line utility, you may prefer to use the standard Docker command-line interface, or the Docker remote API. The weave proxy sits between the docker command or API and the Docker daemon, so that it can automatically attach containers to the weave network.

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

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

Now, containers will always be automatically assigned an IP address and attached to the weave network when we start them. For example:

host1$ docker run -ti ubuntu /bin/sh

More details on IPAM can be found in the IPAM documentation.

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 connected via IPAM or WEAVE_CIDR=..., which are 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.

Limitations

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