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