Feeds

Docker 0.7 has a lover in every port: Containerizer cozies up to Linux distros

New storage drivers let code sandboxes run on stock kernels

Build a business case: developing custom apps

Containerization tech Docker is now supported by all the major Linux distros, making it easier for developers to adopt the lightweight app packaging and shipping tool.

The new capabilities were announced by the open-source project's eponymous parent in a blog post on Tuesday.

Docker is a technology that mates the Linux kernel's LXC, CGroups and Namespaces code to create a lightweight software container.

Where virtual machines each run a guest OS, Docker containerization shares the underlying host OS across all apps running in its sandboxes. It has a lower overhead than typical virtualization.

For instance, Docker could be used to run a database in one container and an app server in another, and the configurable isolation properties let an admin precisely dictate how information is passed between the two.

Version 0.7 now has a storage driver API and three storage drivers – for AUFS, VFS and DEVICEMAPPER – to simplify running Docker on stock Linux distros. Up until it has relied on AUFS for copy-on-write storage, but this code is not part of the Linux kernel so had to be patched in. The new API means it can work with whatever's available from the host system's kernel.

"As of today, Docker no longer requires a patched Linux kernel, thanks to a new storage driver... this means that it will work out-of-the-box on all major distributions, including Fedora, RHEL, Ubuntu, Debian, Suse, Gentoo, Arch, etc," the company wrote.

The new version also includes offline transfer to ease container migration, greater control for port redirects, inter-container communication, and container naming.

Reg readers may point out that Docker's technology is hardly original, as elements of this containerization approach have been present in systems such as Sun Solaris (Zones), and FreeBSD for a long time.

"I think those OSes never enjoyed the adoption that Linux did," said Solomon Hykes, chief technology officer of Docker. "Meanwhile Linux has slowly but surely developed container abilities. For a long time it was quite painful and a lot of work to get linux systems that could operate containers in production at scale."

Docker started in 2008 under the name of Dotcloud and was one of the first companies to start lashing together Linux components to make containerization easier for the lay developer.

Another early adopter was Google, which employed two engineers to develop a tech called "process containers" whose name was later changed to Control Groups (CGroups) and merged into version 2.6.24 of the Linux kernel.

Google, typically, hasn't said much about its own approach to containerization, but the ad-slinger's use of the code is another nod that containerization is a tech with many benefits to organizations.

Now that version 0.7 has been pushed out the door, Hykes is preparing for the long, hard slog to v1.0 of Docker. A development priority here is stabilization, and making it more modular.

"We need to define simple standard APIs for how containers discover each other [and] send network traffic to each other," he said. ®

Maximizing your infrastructure through virtualization

More from The Register

next story
Whoah! How many Google Play apps want to read your texts?
Google's app permissions far too lax – security firm survey
Chrome browser has been DRAINING PC batteries for YEARS
Google is only now fixing ancient, energy-sapping bug
Do YOU work at Microsoft? Um. Are you SURE about that?
Nokia and marketing types first to get the bullet, says report
Microsoft takes on Chromebook with low-cost Windows laptops
Redmond's chief salesman: We're taking 'hard' decisions
EU dons gloves, pokes Google's deals with Android mobe makers
El Reg cops a squint at investigatory letters
Big Blue Apple: IBM to sell iPads, iPhones to enterprises
iOS/2 gear loaded with apps for big biz ... uh oh BlackBerry
OpenWRT gets native IPv6 slurping in major refresh
Also faster init and a new packages system
Google shows off new Chrome OS look
Athena springs full-grown from Chromium project's head
prev story

Whitepapers

Top three mobile application threats
Prevent sensitive data leakage over insecure channels or stolen mobile devices.
The Essential Guide to IT Transformation
ServiceNow discusses three IT transformations that can help CIO's automate IT services to transform IT and the enterprise.
Mobile application security vulnerability report
The alarming realities regarding the sheer number of applications vulnerable to attack, and the most common and easily addressable vulnerability errors.
How modern custom applications can spur business growth
Learn how to create, deploy and manage custom applications without consuming or expanding the need for scarce, expensive IT resources.
Consolidation: the foundation for IT and business transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.