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A rough version of the 'Docker Commandline Tutorial|Running Apache http server inside docker container
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Translate：PaaS under the hood, episode 1: kernel namespaces
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Merge pull request #3 from SleepyHippo/master

PaaS under the hood, episode 1: kernel namespaces
Rename PaaS under the hood, episode 1: kernel namespaces.md to paas-under-the-hood-episode-1-kernel-namespaces.md
clearify some concepts