149 lines
6.2 KiB
Markdown
149 lines
6.2 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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On `$HOST1` run
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host1$ weave launch
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host1$ weave launch-dns
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host1$ weave run --name a1 -ti ubuntu
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The first two lines start the weave router and DNS, each inside their
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own container - this needs to be done once per host. Whilst the
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required docker images are downloaded automatically, there is also a
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`weave setup` command for downloading all the images required for
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weave operation; this is a strictly optional step which is especially
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useful for automated installation of weave and ensures that any
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subsequent weave commands do not encounter delays due to image
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downloading.
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The third line runs our application container, allocating it an IP
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address on the weave network and registering it in DNS. `weave run`
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invokes `docker run -d` behind the scenes, so we could be launching
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any container this way; here we just take a stock ubuntu container and
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launch a shell in it. There's also a `weave start` command, which
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invokes `docker start` for starting existing containers.
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If our application consists of more than one container on this host we
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simply launch them with a variation on third second line.
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Next we repeat similar steps on `$HOST2`...
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host2$ weave launch $HOST1
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host2$ weave launch-dns
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host2$ weave 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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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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On `$HOST1`...
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host1$ docker attach a1
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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, on `$HOST2`...
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host2$ docker attach a2
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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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* [Features](http://docs.weave.works/weave/latest_release/features.html)
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* [Automatic Discovery with WeaveDNS](http://docs.weave.works/weave/latest_release/weavedns.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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