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Showing posts from December, 2013

Experimenting with OpenDJ in CoreOS / Docker

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CoreOS is new minimal Linux based OS designed to run applications in containers.  The design concept is similar to Joyent's SmartOS (aside: I would love to see the CoreOS team adopt ZFS. It has so many compelling features for hosting containers. But I digress...)


CoreOS uses Docker lightweight containers, which are in turn based on Linux LXC containers. You will want to check out the excellent getting started guide, but the readers digest summary is that Docker containers are built up incrementally and inherit from their parent containers.  Each new container contains only the deltas from the parent - making it possible to distribute a small incremental feature set.

When you run a Docker container, you are running only the processes that are needed for your service (for example, OpenDJ). You are not running an entire copy of the OS, making these containers super lightweight (OpenSolaris fans have had this feature for years in the form of zones).

For my OpenDJ experiments, I starte…