LightVM – A new virtualization solution based on Xen

[contingencies]

Great job and nice to see Romania featuring in the news!

To those who just spent the last two years retraining your teams and retooling your infrastructure explicitly for docker (who may show up in this thread embracing and enhancing with a large marketing budget shortly), do take this opportunity to learn the architectural and management/maintenance value of abstraction. ;)

[tinco]

You do realize that Docker containers have an abstract interface and can be run on all OCI runtimes right?

[bmitch3020]

VM's tend to lose the overlay layered filesystem which can dramatically reduce disk usage. Having the filesystem reset to a clean state for every new container is a huge feature of containers. And VM's tend to need predefined dedicated resources for things like memory. A process in a container would only allocate memory when it needs and can free up for other processes to use. It's not all about the startup speed.

That said, VM's have their place, and docker has the option to switch out backends. It's entirely possible to replace runc with some other tool that starts VM's instead of containers. (That's already happening today with Windows containers.)

[tilpner]

An example for such an alternative backend would be runv, which can apparently be used with Docker (though I couldn't get it to work well, but that was probably just my fault)

https://github.com/hyperhq/runv#run-it-with-docker

[jpalomaki]

>Having the filesystem reset to a clean state for every new container is a huge feature of containers.

Could you use file system snapshots for this? Maybe also for the layers?

[monocasa]

Xen is very much inspired by exokernels (you could even make the argument that it is an exokernel), so it makes sense that someone would push it more in that direction.

That being said, if you're going to go that way,it's to bad that there isn't more inspiration from the past 20 years of OS design. A capability based security/object management interface would nice. I also really like Akaros's VM threads model; IMO that'll be the way we end up running what we currently call unikernels.

[CalChris]

it's to bad that there isn't more inspiration from the past 20 years of OS design. A capability based security/object management interface would nice.

Agreed and seL4 comes to mind. It's capability based, quite fast and secure. For that matter, it's also quite small.

[Rusky]

Akaros looks pretty interesting- the M:N aspect is certainly where I think we need to go.

[jeromegn]

The project's page: http://cnp.neclab.eu/projects/lightvm/

[mapsnapps]

If I'm reading this right, that's pretty major. The isolation benefits of a VM with a bootspeed faster than docker?

[tyingq]

https://hypercontainer.io is also in this space. Doesn't boot as fast as docker, but faster than a normal VM.

[wkz]

With the debugging benefits of a brick.

[lbotos]

I haven't been on the server side in a while, but 1) isn't Xen falling out of favor and 2) is docker boot speed a big problem?

[est]

Maybe faster than docker, but how about Intel's Clear Containers?

https://lwn.net/Articles/644675/

[ConfucianNardin]

The Tinyx tool mentioned in the paper doesn't seem to be published anywhere.

It doesn't help that the name was already in use (by a minimal X11 server).

[citrin_ru]

> We achieve lightweight VMs by using unikernels

One problems with unikernels is a lack of debugging/tracing tools (like Dtrace/eBPF): https://www.joyent.com/blog/unikernels-are-unfit-for-product...

[nickik]

That blog post is pretty crappy.

See discussions here: https://news.ycombinator.com/item?id=10953766

[davidthewatson]

How is this different than zerovm?

http://www.zerovm.org/

[burgerdev]

Maybe that ZeroVM is a NaCl sandbox, while LightVM is a Xen VM?

[detaro]

It does not appear to be very similar at all.

[nwrk]

Super excited about this. Amazing progress. Kudos to authors.

[grabcocque]

So, unikernels?

[detaro]

No, not unikernels. They use unikernels and small linux builds for examples to show their improvement of Xen itself.

[detaro]

In case the ACM link isn't available to everyone, here is a copy hosted by NEC: http://cnp.neclab.eu/projects/lightvm/lightvm.pdf

[sctb]

Thanks, we've updated the link from https://dl.acm.org/citation.cfm?id=3132763&CFID=824760366&CF.... I'm not sure I've seen the ACM block traffic like that before.

[michaelmior]

It would be nice if the mods could update to this link since it's accessible by anyone.

[robert_foss]

To save you some time, this is VMs + Unikernels.

[bildung]

Unikernels are mentioned in passing, but are not the cause of the speedup. The main point of the paper is instead the introduction of "LightVM, a complete re-design of the basic Xen control plane optimized to provide lightweight virtualization".

[equalunique]

Unikernels were my first thought. Thank you for the summary.

[metalliqaz]

ACM can't handle the Hacker News flood.

[sitkack]

I have had temporary bans on the ACM for opening 8 papers in a new tab. ACM can't handle the me.