Connecting Containers Directly to External Networks

This article comes from Hasan Mahmood, a staff engineer on the vSphere Integrated Containers team.

With vSphere Integrated Containers (VIC), containers can be connected to any existing vSphere network, allowing for services running on those containers to be exposed directly, and not through the container host, as is the case with Docker today. vSphere networks can be specified during a VIC Engine deployment, and they show up as regular docker networks.

Connecting containers directly to networks this way allows for a clean separation between internal networks that are used for deployment from external networks that are only used for publishing services. Exposing a service in docker requires port forwarding through the docker host, forcing use of network address translation (NAT) as well as making separating networks somewhat complicated. With VIC, you can use your existing networks (and separation that is already there) seamlessly through a familiar docker interface.


To add an existing vSphere network to a VIC Engine install, use the collection of –container-network options for the vic-machine tool. Here is an example run:

The above command installs VIC adding an additional network for containers to use called public. The notation PublicNetwork:public maps an existing distributed port group called PublicNetwork to the name public. After installation, we can see that the public network is visible to docker:

To connect this network, use the –net option to the docker create or run command:

Now that a container is connected to the public network, we need to find out its IP address to access any exported services, in this case, the welcome page for the nginx web server. This can be done by the docker network inspect command, or the docker inspect command. We will use docker network inspect here since the output is more concise:

We now know that our running container’s IP address is Next, we can try reaching nginx via the browser.nginx

This example only offers a very simple example of how to make vSphere networks available to VIC containers.  You can learn more about the different networks that the VIC container host connects to.  Download vSphere Integrated Containers today!