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Comment by geggam | Hacker News Reader

How many companies actually need the scale of Google ? When you are Google you always need more. When you are a smaller company understanding how to control costs is more important.

Capacity planning and actual design of a system is more important for most companies.

I have seen several companies use 3 to 4 times the hardware it needs because they want to do containers or the private cloud thing.

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Can you cite some examples? Did these companies decide to run containers on vm's or just bare metal? In the latter case, they shouldn't need 3 to 4 times more hardware. Your point on capacity planning is well taken. Capacity will always be finite and especially critical to put an upper bound on if doing container based services with multi-tenancy.

Because docker lacks security and we ran docker in a vm

so....

1 VM to run 1 docker container to run 1 jvm .... probably 10 vms per host.... instead of 20 jvms per host

...and we added consul + Haproxy and a few other pieces we didnt need ( think srv records ) ... which added yet more hardware

> 1 VM to run 1 docker container to run 1 jvm .... probably 10 vms per host.... instead of 20 jvms per host

That doesn't make sense, the Linux overhead is not enough to make it that much less dense. You get better HA by running 20 VM's instead of 20 JVM's because machines crash taking out 20 apps instead of 1. I know the physical host can crash taking out 20 hosts, but you have that problem in either scenario.

I have yet to work at a place where making sense was the driving factor for technology choices :)

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