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Ask HN: Why unikernels are not more popular?

2 points by amirouche 7y ago

I discovered MirageOS. I find the idea elegant. It looks to me like a compiler of the whole Operating System. I wondering what are the pros and cons? How does they relate to micro kernels?

PaulHoule 7y ago
It is hard to innovate in operating systems because people already have a lot of software written for POSIX and POSIX-like systems and if you wanted to make something entirely different people won't like it. The Unikernel idea is one of the better ones. I've thought a lot about what an async-first operating system would look like and it is hard to picture, particularly when virtual memory is a fundamentally blocking abstraction.
eyberg 7y ago
The main reason I've found is that very few people/organizations have focused on making it a first class citizen. A weekend hacker or two might work for a new web framework but unikernels involve entire operating system development. To compare - linux has been around for ~ 30 years. This is something we are focused on at NanoVMs. (yes, I work there). As for the other questions - unikernels descend from the microkernel family tree and some implementations (ours included) blur that line considerably. Andrew Tanenbaum was right. :) Pros: * many are much faster than comparable linux applications for boot and runtime (NEC can boot theirs in 5ms - fork takes ~3ms, docker containers boot in ~200ms) * many are dramatically more secure (ours has the same aslr/page protections as linux does yet also doesn't have the notion of a shell, users or the ability to run other processes) * if you have your own infrastructure you can massively consolidate your vms (this is a big benefit but you won't get this on public cloud) Cons: * in the past you had to manually port your application (this was too much to ask a user for) -- this is changing in many different implementations * there are some hard constraints (eg: single process) for a lot of implementations (for instance postgres would need to be re-written)
billconan 7y ago
https://www.joyent.com/blog/unikernels-are-unfit-for-production https://www.joyent.com/blog/unikernels-are-unfit-for-product... https://fourlightyears.blogspot.com/2018/08/what-i-could-not-undiscover-about.html https://fourlightyears.blogspot.com/2018/08/what-i-could-not...
- eyberg 7y ago
  Just to point out for the first article (unikernels are undebuggable) - there's been a lot of work done in the past few years that effectively completely nullifies that argument: https://nanovms.com/blog/common-unikernel-debugging-myths-debunked https://nanovms.com/blog/common-unikernel-debugging-myths-de... https://www.nccgroup.trust/us/about-us/newsroom-and-events/blog/2019/january/xendbg-a-full-featured-debugger-for-the-xen-hypervisor/ https://www.nccgroup.trust/us/about-us/newsroom-and-events/b... https://www.linux.com/blog/event/xen-summit/2017/9/uniprof-transparent-unikernel-performance-profiling-and-debugging https://www.linux.com/blog/event/xen-summit/2017/9/uniprof-t... https://github.com/rumpkernel/wiki/wiki/Howto:-Debugging-Rumprun-with-gdb https://github.com/rumpkernel/wiki/wiki/Howto:-Debugging-Rum...
amirouche 7y ago
An overview of unikernels https://github.com/cetic/unikernels https://github.com/cetic/unikernels

2 points by amirouche 7y ago

I discovered MirageOS. I find the idea elegant. It looks to me like a compiler of the whole Operating System. I wondering what are the pros and cons? How does they relate to micro kernels?

PaulHoule 7y ago

It is hard to innovate in operating systems because people already have a lot of software written for POSIX and POSIX-like systems and if you wanted to make something entirely different people won't like it. The Unikernel idea is one of the better ones. I've thought a lot about what an async-first operating system would look like and it is hard to picture, particularly when virtual memory is a fundamentally blocking abstraction.

eyberg 7y ago

The main reason I've found is that very few people/organizations have focused on making it a first class citizen. A weekend hacker or two might work for a new web framework but unikernels involve entire operating system development. To compare - linux has been around for ~ 30 years. This is something we are focused on at NanoVMs. (yes, I work there). As for the other questions - unikernels descend from the microkernel family tree and some implementations (ours included) blur that line considerably. Andrew Tanenbaum was right. :) Pros: * many are much faster than comparable linux applications for boot and runtime (NEC can boot theirs in 5ms - fork takes ~3ms, docker containers boot in ~200ms) * many are dramatically more secure (ours has the same aslr/page protections as linux does yet also doesn't have the notion of a shell, users or the ability to run other processes) * if you have your own infrastructure you can massively consolidate your vms (this is a big benefit but you won't get this on public cloud) Cons: * in the past you had to manually port your application (this was too much to ask a user for) -- this is changing in many different implementations * there are some hard constraints (eg: single process) for a lot of implementations (for instance postgres would need to be re-written)

billconan 7y ago

https://www.joyent.com/blog/unikernels-are-unfit-for-production https://www.joyent.com/blog/unikernels-are-unfit-for-product... https://fourlightyears.blogspot.com/2018/08/what-i-could-not-undiscover-about.html https://fourlightyears.blogspot.com/2018/08/what-i-could-not...

eyberg 7y ago
Just to point out for the first article (unikernels are undebuggable) - there's been a lot of work done in the past few years that effectively completely nullifies that argument: https://nanovms.com/blog/common-unikernel-debugging-myths-debunked https://nanovms.com/blog/common-unikernel-debugging-myths-de... https://www.nccgroup.trust/us/about-us/newsroom-and-events/blog/2019/january/xendbg-a-full-featured-debugger-for-the-xen-hypervisor/ https://www.nccgroup.trust/us/about-us/newsroom-and-events/b... https://www.linux.com/blog/event/xen-summit/2017/9/uniprof-transparent-unikernel-performance-profiling-and-debugging https://www.linux.com/blog/event/xen-summit/2017/9/uniprof-t... https://github.com/rumpkernel/wiki/wiki/Howto:-Debugging-Rumprun-with-gdb https://github.com/rumpkernel/wiki/wiki/Howto:-Debugging-Rum...

amirouche 7y ago

An overview of unikernels https://github.com/cetic/unikernels https://github.com/cetic/unikernels