Like FreeBSD Jails and Solaris Zones, Linux containers are self-contained execution environments—with their own, isolated CPU, memory, block I/O, and network resources—that share the kernel of the host operating system. The result is something that feels like a virtual machine, but sheds all the weight and startup overhead of a guest operating system.
In a large-scale system, running VMs would mean you are probably running many duplicate instances of the same OS and many redundant boot volumes. Because containers are more streamlined and lightweight compared to VMs, you may be able to run six to eight times as many containers as VMs on the same hardware.
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