147 lines
6.1 KiB
Markdown
147 lines
6.1 KiB
Markdown
# Weave - weaving containers into applications
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[](https://travis-ci.org/weaveworks/weave) [](https://circleci.com/gh/weaveworks/weave) [](https://coveralls.io/r/weaveworks/weave)
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Weave creates a virtual network that connects Docker containers
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deployed across multiple hosts and enables their automatic discovery.
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Applications use the network just as if the containers were all
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plugged into the same network switch, with no need to configure port
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mappings, links, etc. Services provided by application containers on
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the weave network can be made accessible to the outside world,
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regardless of where those containers are running. Similarly, existing
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internal systems can be exposed to application containers irrespective
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of their location.
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Weave can traverse firewalls and operate in partially connected
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networks. Traffic can be encrypted, allowing hosts to be connected
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across an untrusted network.
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With weave you can easily construct applications consisting of
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multiple containers, running anywhere.
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Weave works alongside Docker's existing (single host) networking
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capabilities, so these can continue to be used by containers.
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## Installation
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Ensure you are running Linux (kernel 3.8 or later) and have Docker
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(version 1.3.1 or later) installed. Then install weave with
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sudo curl -L git.io/weave -o /usr/local/bin/weave
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sudo chmod a+x /usr/local/bin/weave
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CoreOS users see [here](https://github.com/fintanr/weave-gs/blob/master/coreos-simple/user-data) for an example of installing weave using cloud-config.
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Weave respects the environment variable `DOCKER_HOST`, so you can run
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it locally to control a weave network on a remote host.
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## Quick Start Screencast
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<a href="http://youtu.be/k6r7yuSr0hE" alt="Click to watch the screencast" target="_blank">
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<img src="/docs/hello-screencast.png" />
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</a>
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## Example
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Say you have docker running on two hosts, accessible to each other as
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`$HOST1` and `$HOST2`, and want to deploy an application consisting of
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two containers, one on each host.
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First start weave on $HOST1:
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host1$ weave launch && weave launch-dns && weave launch-proxy
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this runs the weave router, DNS and Docker API proxy, each in their
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own container. Next we configure our `DOCKER_HOST` environment
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variable to point to the proxy, so that containers launched via the
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docker command line are automatically attached to the weave network:
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host1$ eval $(weave proxy-env)
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Finally we run our application container; this happens via the proxy
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so it is automatically allocated an IP address and registered in DNS:
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host1$ docker run --name a1 -ti ubuntu
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That's it! If our application consists of more than one container on
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this host we simply launch them with `docker run` as appropriate.
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Next we repeat similar steps on `$HOST2`...
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host2$ weave launch $HOST1 && weave launch-dns && weave launch-proxy
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host2$ eval $(weave proxy-env)
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host2$ docker run --name a2 -ti ubuntu
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The only difference, apart from the name of the application container,
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is that we tell our weave that it should peer with the weave on
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`$HOST1` (specified as the IP address or hostname, and optional
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`:port`, by which `$HOST2` can reach it). NB: if there is a firewall
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between `$HOST1` and `$HOST2`, you must open the weave port (6783 by
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default; this can be overriden by setting `WEAVE_PORT`) for TCP and
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UDP.
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Note that we could instead have told the weave on `$HOST1` to connect to
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`$HOST2`, or told both about each other. Order does not matter here;
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weave automatically (re)connects to peers when they become
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available. Also, we can tell weave to connect to multiple peers by
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supplying multiple addresses, separated by spaces. And we can
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[add peers dynamically](http://docs.weave.works/weave/latest_release/features.html#dynamic-topologies).
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The router, DNS and Docker API proxy need to be started once per
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host. The relevant container images are pulled down on demand, but if
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you wish you can preload them by running `weave setup` - this is
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particularly useful for automated deployments, and ensures that there
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are no delays during later operations.
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Now that we've got everything set up, let's see whether our containers
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can talk to each other...
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In the container started on `$HOST1`...
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root@a1:/# ping -c 1 -q a2
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PING a2.weave.local (10.160.0.2) 56(84) bytes of data.
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--- a2.weave.local ping statistics ---
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1 packets transmitted, 1 received, 0% packet loss, time 0ms
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rtt min/avg/max/mdev = 0.341/0.341/0.341/0.000 ms
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Similarly, in the container started on `$HOST2`...
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root@a2:/# ping -c 1 -q a1
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PING a1.weave.local (10.128.0.2) 56(84) bytes of data.
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--- a1.weave.local ping statistics ---
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1 packets transmitted, 1 received, 0% packet loss, time 0ms
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rtt min/avg/max/mdev = 0.366/0.366/0.366/0.000 ms
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So there we have it, two containers on separate hosts happily talking
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to each other.
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## Find out more
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* [Documentation homepage](http://docs.weave.works/weave/latest_release/)
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* [Getting Started Guides](http://weave.works/guides/)
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* [Features](http://docs.weave.works/weave/latest_release/features.html)
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* [Troubleshooting](http://docs.weave.works/weave/latest_release/troubleshooting.html)
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* [Building](http://docs.weave.works/weave/latest_release/building.html)
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* [How it works](http://docs.weave.works/weave/latest_release/how-it-works.html)
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## Contact Us
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Found a bug, want to suggest a feature, or have a question?
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[File an issue](https://github.com/weaveworks/weave/issues), or email
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help@weave.works. When reporting a bug, please include which version of
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weave you are running, as shown by `weave version`.
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Follow weave on Twitter:
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[@weaveworks](https://twitter.com/weaveworks).
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Read the Weave blog:
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[Weaveblog](http://weaveblog.com/).
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IRC:
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[#weavenetwork](https://botbot.me/freenode/weavenetwork/)
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