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Operating Systems Still Matter In a Containerized World
New submitter Jason Baker writes: With the rise of Docker containers as an alternative for deploying complex server-based applications, one might wonder, does the operating system even matter anymore? Certainly the question gets asked periodically. Gordon Haff makes the argument on Opensource.com that the operating system is still very much alive and kicking, and that a hardened, tuned, reliable operating system is just as important to the success of applications as it was in the pre-container data center.
Modern virtualization doesn't have the overhead the GP cited; the 20% RAM loss and 30% CPU capacity loss numbers cited by the AC you responded to are absurd fabrications. I use KVM on Debian hosts to power a large number of VMs running a variety of operating systems, and the loss of CPU bandwidth and throughput with guests is negligible due to hardware virt extensions in modern CPUs (where "modern" in fact means "most 64-bit AMD and Intel CPUs from the last few years, plus a small number of 32-bit CPUs"). Using the "host" CPU setting in guests can also directly expose all host CPU facilities, resulting in virtually no losses in capabilities for mathematically-intensive guest operations. As far as memory is concerned, far from resulting in a 20% loss of available RAM, I gain a significant amount of efficiency in overall memory utilization using KSM (again, used with KVM). On a host running many similar guests, extremely large gains in memory deduplication may be seen. Running without KSM doesn't result in significant memory consumption overhead either, as KVM itself hardly uses any RAM.
The only significant area of loss seen with modern virtualization is disk IO performance, but this may be largely mitigated through use of correctly tuned guest VM settings and updated VirtIO drivers. The poster you replied to is ignorant at best, and trolling at worst.
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