Microservices in general, and container networking technology in particular, are all the rage these days, but new survey data shows that container networking technology remains a fundamental challenge. In fact, a new “Container Market Adoption Survey” report released this week by ClusterHQ, a provider of data management tools for deploying containers on a persistent storage platform, finds that networking ranks second, after storage, in terms of barriers associated with deploying containers.

Undoubtedly, networking will be a major focus of the Dockercon 2016 conference held the week of June 20 in Seattle. For example, PLUMgrid will be showcasing a networking plug-in for its Open Networking Suite (ONS) software-defined networking (SDN) platform, which provides support for multihost networking, security, DNS, tunneling, and high availability to Docker containers.

Container Networking Opportunity

Just about every other provider of network virtualization (NV) overlays sees the opportunity that containers present. In addition to all the existing flavors of virtual machines that need to be networked together, containers will wind up being deployed on bare metal servers and platform-as-a-service environments, as well as on virtual machines.

“We see multiple scenarios,” says Wendy Cartee, vice president of product management and marketing for PLUMgrid. “There are a lot containers running on VMs.”

Brad Casemore, an industry analyst for International Data Corp., says all that container fluidity will be a major challenge for IT organizations to absorb. “The big issue is going to be visibility,” says Casemore. “Containers are going to be running everywhere.”

At the core of any networking initiative is an application programming interface (API) developed by Docker Inc. that makes it possible to distribute Docker components across multiple servers. The core element of the Docker Network API is an Ethernet bridge, dubbed “docker0,” which creates a virtual subnet inside a Linux kernel running on the Docker host. It can pass packets back and forth between containers on that host. Docker also provides a pair of virtual Ethernet interfaces on each container that randomly assign an IP address and a subnet to be used by the host machine. The upside of this approach is that it means developers don’t have to get involved in assigning IP addresses.

Docker and OVS Options

The best news is that Docker also allows IT organizations to replace its default networking functions with Open vSwitch (OVS) and other native Linux container networking elements. A variety of networking vendors have been working to leverage that capability to support distributed container applications running across multiple servers running in different data centers. Using a combination of network overlays and SDN technologies, the goal is to make it easier for network administrators to limit container sprawl by giving them the tools needed to manage containers alongside what is rapidly becoming a wide variety of host computer systems inside the enterprise.

How all this will play out in the months and years ahead remains to be seen. Some vendors contend containers and microservices will force IT organizations to reevaluate their entire networking strategies, using tools such as Libchan that run in memory. Others suggest it will be simpler to extend existing network architectures to support containers. Regardless of the outcome, the enterprise IT environment is about to become a lot more dynamic than it’s ever been. The degree to which network administrators can adapt to those changes will, in many cases, ultimately define the role networking professionals will play in the enterprise going forward.