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Comment by im_down_w_otp | Hacker News Reader

I don't entirely understand what's happening here. The title and the post talk a lot about "Bare-Metal", but it also seems to indicate that everything is hosted on servers running Ubuntu. Which, if accurate, seems to be Kubernetes running on Linux, not bare-metal?

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Kubernetes relies on containers, which are made out of cgroups and namespaces. Those are Linux features, so there's no way around that.

This is as bare-metal as it gets since it's not running on a VM.

Point here is that term bare-metal cannot apply to applications relying on OS features. Unikernels are the closest thing you can use this term in this area.

Wikipedia [0] doesn't agree with you (neither do I, but who am I anyway?):

"A bare-metal server is a computer server that hosts one tenant, or consumer, only.[1] The term is used for distinguishing between servers that can host multiple tenants and which utilize virtualisation and cloud hosting.[2] Such servers are used by a single consumer and are not shared between consumers. Each server may run any amount of work for a user, or have multiple simultaneous users, but they are dedicated entirely to the entity who is renting them. Unlike servers in a data centre, they are not being shared between multiple customers.

Bare-metal servers are physical servers. Each server offered for rental is a distinct physical piece of hardware that is a functional server on its own. They are not virtual servers running in multiple pieces of shared hardware."

[0] https://en.wikipedia.org/wiki/Bare-metal_server

See https://en.wikipedia.org/wiki/Bare_machine. Quoting the important part:

> In computer science, bare machine (or bare metal) refers to a computer executing instructions directly on logic hardware without an intervening operating system.

Bare-metal server has indeed been used to refer to non-virtualized servers, but it's a misnomer. The current terminology for this is "dedicated server".

I've never heard of that before. Besides, dedicated server is an unfortunate term in practice either; I may pay Hetzner for a bunch of dedicated servers, some run a bunch of VMs, some run Kafka without a virtualization layer. My services in containers on Kubernetes in VMs on dedicated servers are still running on dedicated servers, but definitely not what I'd call bare metal. In my experience, calling the Kafka server "bare metal" is understood by everyone, used by pretty much everyone I've come across and doesn't get mixed up with adjacent concepts so easily. Maybe that's different in niche/research circles where "bare machine" is a concept that's actually relevant in day-to-day work, I wouldn't know. As far as I'm aware, the term is very much alive and kicking.

I think you'll find that hardware/embedded development is not a niche industry.

A misnomer repeated a thousand times by a thousand different people becomes a/the new meaning. It's how human languages work and evolve or change over time.

Today when most tech people talk about bare metal they refer to a server that is not virtual.

It is still insignificant compared to the original terminology, which is heavily used in hardware/embedded to distinguish between the use of an OS (embedded RTOS, Linux, etc.) vs. direct programming.

I wouldn't put much stock in page made just in 2016 that started like this https://en.wikipedia.org/w/index.php?title=Bare-metal_server...

It has to start with something. It would be a lot weirder if the first revision had been a white paper.

If you disagree with what's on the page, please add or edit the information there. With proper references, it will be appreciated by everyone that uses Wikipedia.

I'm saying the term is much older than this, don't be obtuse.

Most terms are much older than their corresponding Wikipedia pages. I'm really failing to see your point here.

It is possible to run containers directly on top of type 1 hypervisors.

If you mean something like runV which runs Linux kernel in a lightweight VM still then how does that move the needle in the bare-metal direction exactly?

This is not how I've heard any of my coworkers define bare-metal. Obviously anecdotal, but I think you are in the minority here.

Turns out, the minority is right FWIW.

But you still can't stop language from changing no matter how "right" you are you.

Seems like a wasted term for something only 10 people in the world will care about doing.

Even Apple named their API Metal in reference to existing phrases like "running close to the metal" back in 2014 and even then it raised some eyebrows in my opinion, but that usage is still miles better than basically saying you're running a program normally. Since when absence of virtualization requires articles to be written about?

Should we unpack these statements though?

How much of linux isn't about cgroups and namespaces? Docker I believe needs about a 100 system calls to get containers to work. How much of the tree could you shake and still have containers work? Would you still call the host Linux, or something else? And what would that system do for Windows and OS X users? Anything?

Could you maintain this 'something else' as a permanent fork, a la Red Hat?

It appears there's two camps in the audience. The camp I'm familiar with (and it appears the author as well) use bare-metal to mean running on your own computers (either in-house or colo) instead of in a VM on a cloud provider.

I am yet to come across usage where the context doesn't make it unambiguous what it means. It can mean both things at the same time.

I agree, I'm just saying that both sides are understandably confused because its clear that both sides were unfamiliar with the other meaning.

Just call it physical or dedicated servers.

Everyone is right. Each group have their own background or silo or bubble or industry and each can use the word. Nobody can claim exclusive ownership unless they have a trademark. The one that still boggles my little mind is "Apple". How a company can own exclusive rights to that I will never understand, regardless of how many times a lawyer explains it to me.

Bare-metal refers to running on hardware directly (vs. running on VMs or the cloud). I'm interested to know what you thought it was.

Traditionally “bare-metal” would refer to running directly on physical hardware with no operating system. In the context of cloud providers, “metal” does now seem to mean “doesn’t run in a VM” but to varying extents. Seems like an unnecessary overload.

In the dark ages, when running an OS in the way you're referring to 'bare metal' was the default, it meant running something without a traditional kernel underneath it.

Not many things are written to do that, of course. Oracle used to offer an installation mode like this. It was generally a gimmick - you pay for a tiny bit of performance with a ton of flexibility. There are probably use cases where it makes sense, but not that many.

Yeah, but it was a super niche term back then. After 2010, at least, bare metal was used a lot more for: "running the OS we need (+ app) directly on a physical server".

This usage has been, in my experience, a lot more widespread.

Hmm - what's the overlap between your definition of "bare metal" and the current definition of "embedded"?

I will say, this comment section is the first time I'm hearing about "bare-metal" meaning "without an OS", but the above question is genuine curiosity.

Those terms are orthogonal. Embedded typically refers to running on some HW that is not typically thought of as a computer. Embedded SW can run within an OS or on bare metal.

> Oracle used to offer an installation mode like this

Oracle, and BEA before them, used to offer a JVM which ran on top of a thin custom OS designed only to host the JVM, you could call it a "unikernel". Product was called JRockit Virtual Edition (JRVE), WebLogic Server Virtual Edition (WLS-VE, when used to run WebLogic), earlier BEA called it LiquidVM. The internal name for that thin custom OS was in fact "Bare Metal". Similar in concept to https://github.com/cloudius-systems/osv but completely different implementation

I think one thing which caused a problem for it, is a lot of customers want to deploy various management tools to their VMs (security auditing software, performance monitoring software, etc) and when your VM runs a custom OS that becomes very difficult or impossible. So adopting this product could lead to the pain of having to ask for exceptions to policies requiring those tools and then defending the decision to adopt it against those who use those policies to argue against it. I think this is part of why the product was discontinued.

Nowadays, Oracle offers "bare metal servers" [1] – which are just hypervisor-less servers, same as other cloud vendors do. Or similarly, "Oracle Database Appliance Bare Metal System" [2] – which just means not installing a hypervisor on your Oracle Database Appliance.

So Oracle seems to have a history of using the phrase "bare metal" in both the senses being discussed here.

[1] https://www.oracle.com/cloud/compute/bare-metal.html

[2] https://docs.oracle.com/en/engineered-systems/oracle-databas...

to me, running on "bare metal" means part of your program is setting up the clock for various buses and CPU and you have another little program who's job is to jump to the first address of your real program.

https://en.wikipedia.org/wiki/Bare_machine

> In computer science, bare machine (or bare metal) refers to a computer executing instructions directly on logic hardware without an intervening operating system.

https://en.wikipedia.org/wiki/Bare-metal_server

Yes, I mentioned elsewhere that this has been used to refer to dedicated servers, but it's a marketing misnomer.

Im surprised you've been downvoted as much as you have. It appears bare metal has a very specific meaning in certain contexts. For what its worth, it also has a very specific meaning in cloud provider contexts, which is exactly what you've defined here.

Directly on the hardware. It's the only definition of the term that I'm familiar with. Like the difference between writing your application and managing lifecycle and peripheral access all yourself directly to your MCU vs. using an RTOS to provide you facilities for task scheduling and I/O primitives, etc.

I've never before encountered, "Includes a full feature-rich OS" as "bare-metal" before. Reading the title I assumed someone managed to get some flavor of Kubernetes running right on the hardware as the lowest-level software layer of the system. That would have meant bare-metal to me. What's described here is running Kubernetes on a physical host rather than a virtual host from what I can tell, but it's not running Kubernetes "bare-metal" because between Kubernetes and the "metal" is Linux.

Or at least that's what it would mean in my world, but the interpretation appears to be different for others. Outside of confusion, I was also just disappointed. This article is just basically setting up Kubernetes. That it's on a physical host is a lot less interesting and novel to me than if they'd managed to implement some shape of Kubernetes as the OS itself, which is what I'd originally interpreted the title to mean.

Running Kubernetes on Ubuntu is a bad idea especially if it is multitenant. You can have a lot of security issues there as users can run anything on those nodes. This exercise is far from production

What's the problem with Ubuntu specifically (vs ex. Alpine or RHEL)?

I guess "bare-metal" is Newspeak for "running directly on hardware without a hypervisor".

It's not "Newspeak". Kubernetes is an application, it runs on an OS. You can call it "Newspeak" if you consider anything after VMs became super popular "Newspeak" (around 2010, I think?).

Bare-metal = no VMs or other virtualization involved.

It is somewhat "newspeak", as bare metal has meant "without an OS" in the embedded space for a very long time. This is just a case of two different spaces using the same term for different ideas.

Sometimes terms are overloaded for different domains. This is pretty common; no need to argue about which is The One True Definition.

Hence, "just a case".

But that's not (Orwellian) newspeak at all, is it? That term carries some very strong negative connotations.

I did couch it with "somewhat". Though it does fit the theme of a diminished meaning for the same word, since the newer meaning is a much simpler thing to do.

Bare metal has meant "whithout a supervisor" to operations for more than a decade. It has also meant "without an emulator" to the emulation community for a really long time.

I imagine it also has some meaning for the music community.

Sure. For comparison, I can find references to "bare metal" meaning "no operating system" dating back to 1989...3 decades:

https://apps.dtic.mil/dtic/tr/fulltext/u2/a219356.pdf (search for bare-metal)

I suspect it comes from the automotive paint industry. Sanding down to the "bare metal" for the best finish...where the primer and paint are as close to the substrate as they can be.

You mean it's Newspeak for "running under a supervisor, but without the supervisor running under a hypervisor".

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