What are containers and how do they work?

What’s the hype?

Containers have hit the mainstream alongside virtual machines (VMs). Industry titans like Google, Docker, Linux and Amazon have embraced them with open arms. But what exactly are containers and, more importantly, do they live up to hype?

Background

Containers have been around for a while, but only recently found footing in the telecom industry. They came to fame when open source software container platform provider Docker developed a way to break down large monolithic applications into small bits of code, and run them on a single operating system (OS). The technology is by its nature granular and lightweight, isolating various resources like memory and CPU from the host OS.

Containers are based upon the transportation industry’s use of intermodal containers, which allow cargo to move across multiple modes of transportation, such as trucks, trains, ships and aircraft, without being reloaded. Manufacturers originally prepared different sized containers to ship bulk, which was both burdensome and time-consuming. Intermodal containers addressed this issue by standardizing the size of shipments. Similarly, Docker helped draw up a set of specifications for storing objects in the IT industry.

An alternative to VMs

One reason the technology has become popular is it provides a way to run multiple, isolated applications on a single server without the use of VMs. VMs can be spun up on inexpensive nodes to perform various network functions, such as firewall or encryption, automatically. The main difference between the two is VMs run on top of a hypervisor that sits on top of an OS; whereas containers run on a single OS and share the same kernel. The benefit of the latter is they do not consume as many resources, including memory and CPU, as the former.

Benefits

Containers can offer businesses several advantages. Since containers do not require separate OS instances, multiple devices can be stored on the same infrastructure. Moreover, with the technology, developers can rest assure their software can run anywhere — regardless of where it is deployed. In addition, since the devices have a low overhead and are lightweight, they can be created quickly. Better yet, Docker’s containers are free to download and easy to install.

Drawbacks

No technology is without its shortcomings. The portable systems are more vulnerable to network intrusions than VMs since they share an OS kernel, giving hackers total access to the network. Furthermore, the devices are easy to create and duplicate. Having too many can consume a host’s physical resources, including CPU and memory, if left unattended. In addition, some of the tools needed to monitor the technology have yet to come to fruition. VM tools may be used as a temporary substitute to help manage network security as new tools are developed.

Containers will continue to mature in the open source market. It is expected the devices will work with VMs to create better cloud portability.