129 lines
5.4 KiB
Markdown
129 lines
5.4 KiB
Markdown
---
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title: Visualizing Weave Net in Weave Cloud
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menu_order: 30
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search_type: Documentation
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---
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Weave Net provides a simple to deploy networking solution for containerized apps. Here, we describe how to manage a Weave container network using a sample application which consists of two simple `netcat` services deployed to containers on two separate hosts.
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This section contains the following topics:
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* [Signing in to Weave Cloud](#signing-in)
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* [Launching Weave Net](#launching)
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* [Launching on Additional Hosts](#peer-connections)
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* [How Peer Discovery Works](#how-it-works)
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### <a name="signing-in"></a>Signing in to Weave Cloud
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Weave Cloud is a fast and simple way to visualize, manage and monitor
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containers and microservices. In order to use Weave Cloud to set up
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Weave Net, you must sign up to Weave Cloud and create an "Instance".
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The instance will have a Service Token which is a 32-character string
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used to uniquely identify it. Get hold of the Service Token for your
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Instance, as shown below:
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For the purpose of these instructions we will use a dummy Service
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Token `dk6hz1acdd58aea6b75migoy4axqasdf`.
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### <a name="launching"></a>Launching Weave Net
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Before launching Weave Net and deploying your apps, ensure that Docker
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is [installed](https://docs.docker.com/engine/installation/) on both
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hosts.
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On `$HOST1` run:
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host1$ weave launch --token=dk6hz1acdd58aea6b75migoy4axqasdf
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host1$ eval $(weave env)
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host1$ docker run --name a1 -ti weaveworks/ubuntu
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Where,
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* The first line runs Weave Net.
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* The second line configures the Weave Net environment, so that containers launched via the Docker command line are automatically attached to the Weave network, and,
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* The third line runs the [application container](/site/faq.md#own-image) using [a Docker command](https://docs.docker.com/engine/reference/run/).
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> **Note** If the first command results in an error like
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> ```
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> Cannot connect to the Docker daemon. Is the docker daemon running on this host?
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> ```
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> then you likely need to be 'root' in order to connect to the Docker
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> daemon. If so, run the above and all subsequent commands in a
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> *single* root shell:
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> ```
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> host1$ sudo -s
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> host1# weave launch --token=dk6hz1acdd58aea6b75migoy4axqasdf
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> host1# eval $(weave env)
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> host1# docker run --name a1 -ti weaveworks/ubuntu
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> ```
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> Do *not* prefix individual commands with `sudo`, since some commands
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> modify environment entries and hence they all need to be executed from
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> the same shell.
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Weave Net must be launched once per host. The relevant container images will be pulled down from Docker Hub on demand during `weave launch`.
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You can also preload the images by running `weave setup`. Preloaded images are useful for automated deployments, and ensure there are no delays during later operations.
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If you are deploying an application that consists of more than one container to the same host, launch them one after another using `docker run`, as appropriate.
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### <a name="peer-connections"></a>Launching on Additional Hosts
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To launch Weave Net on an additional host and create a peer
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connection, run exactly the same commands as on the first host:
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host2$ weave launch --token=dk6hz1acdd58aea6b75migoy4axqasdf
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host2$ eval $(weave env)
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host2$ docker run --name a2 -ti weaveworks/ubuntu
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Because you are using Weave Cloud, the second peer will discover the
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first and automatically create a connection to it.
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>**Note:** If there is a firewall between `$HOST1` and `$HOST2`, you must permit traffic to flow through TCP 6783 and UDP 6783/6784, which are Weave’s control and data ports.
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Now you can proceed to [test container communications](/site/install/using-weave#testing)
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### <a name="how-it-works"></a>How Peer Discovery Works
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The Weave Cloud back-end maintains a database of all the peers that
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have registered in each instance. You can create as many instances as
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you like in the Weave Cloud console: for different projects, or to
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separate test and production.
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As each peer starts up, it looks for all network instances that
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another peer might be able to contact it on, and registers those with the back-end.
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If you want to control which addresses are used, add the `--advertise-address` flag:
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host1$ weave launch --token=dk6hz1acdd58aea6b75migoy4axqasdf --advertise-address=192.0.2.1,198.51.100.4
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When the new peer registers itself, it also fetches a list of all
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other peers in the instance, and begins to contact them.
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If the peer cannot contact the Weave Cloud back-end it will print an
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error message in its log and exit. To check the logs run:
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host1$ docker logs weave
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When a Weave Net instance is formed for the first time, the peers must
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initialize the [IP Allocation Manager](/site/tasks/ipam/ipam.md). This process,
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and the configuration options available, are unchanged when using
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Weave Cloud.
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When you shut down a peer for good, use [the `weave reset`
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command](/site/tasks/ipam/stop-remove-peers-ipam.md) and it will be removed
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from the Weave Cloud database so future peers will not attempt to
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connect to it.
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**See Also**
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* [Installing Weave Net](/site/install/installing-weave.md)
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* [Launching Weave Net](/site/install/using-weave.md)
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* [Using Fastdp With Weave Net](/site/tasks/manage/fastdp.md)
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* [Integrating Docker via the Network Plugin (Legacy)](/site/install/plugin/plugin.md)
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* [Integrating Docker via the Network Plugin (V2)](/site/install/plugin/plugin-v2.md)
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