The potential impact of containers on networks

Networking is a crucial component in the container ecosystem, providing connectivity between containers running on the same host as well as on different hosts.

IDG Tech Spotlight  >  Containers + Virtualization [ Network World / March 2020 ]
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Containers have emerged over the past several years to provide an efficient method of storing and delivering applications reliably across different computing environments. By containerizing an application platform and its dependencies, differences in OS distributions and underlying infrastructures are abstracted away. 

Networking has emerged as a critical element within the container ecosystem, providing connectivity between containers running on the same host as well as on different hosts, says Michael Letourneau, an IT architect at Liberty Mutual Insurance. "Putting an application into a container automatically drives the need for network connectivity for that container," says Letourneau, whose primary focus is on building and operating Liberty Mutual's container platform. 

Virtualization evolution 

Container networking is part of an evolution in the virtualization of storage, compute and networking technologies that began over a decade ago with PC/machine virtualization. "Early on, it was recognized that virtualization of the physical machine had all sorts of benefits around cost, speed and ease of development," says Thomas Nadeau, technical director of network function virtualization at open-source software provider and IBM subsidiary  Red Hat

With virtualization, hardware resources are shared by virtual machines, each of which include both an application and a complete operating system instance. A physical server running three VMs, would, for example, feature a hypervisor accompanied by three separate operating systems running on top. On the other hand, a server supporting three containerized applications requires just a single operating system, with each container sharing the operating system kernel with its companion containers. 

While a VM with its own complete operating system may consume several gigabytes of storage space, a container might be only be tens of megabytes in size. Therefore, a single server can host many more containers than VMs, significantly boosting data-center efficiency while reducing equipment, maintenance, power and other costs. 

Following the right container-networking approach is critical to long-term success.

Choosing the right approach to container networking depends largely on application needs, deployment type, use of orchestrators and underlying OS type. "Most popular container technology today is based on Docker and Kubernetes, which have pluggable networking subsystems using drivers," explains John Morello, vice president of product management, container and serverless security at cybersecurity technology provider Palo Alto Networks. "Based on your networking and deployment type,

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