Container virtualization for Linux is by no means new: In addition to the classical Linux containers (LXC) [1], OpenVZ [2] has been around for some years as a pioneer. That said, containers were unable to assert themselves in direct competition with full virtualizers for several reasons (see the "Virtualization Solutions" box). The Docker implementation of Linux containers quickly captured the hearts and minds of admins and developers and has sustained its popularity for more than two years now.

However, Docker suffers from serious problems in everyday use at the data center, not the least of which is playing nice with OpenStack. As a result, alternatives have been shooting out of the ground, including Canonical's player, LXD [3], which was announced at the OpenStack Summit in Paris, France, last year. The timing and venue were no accident: LXD is designated to become Canonical's mainstay in the container virtualization market for OpenStack and thus open up a line of business that the major manufacturers have neglected for a long time.

How does LXD differ from Docker? How does the solution work, and does it really collaborate that well with OpenStack? Linux Magazine took a close look at the first alpha versions of LXD, and the reviewers were quite impressed by what the Shuttleworth developers have served up.

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