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My struggle from a UNIX background in the modern "cloud" world
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this post was submitted on 10 Oct 2023
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That's the problem. The reason Unix became so popular is because it has a highly integrated design and a few very reused abstractions. A lot of simple parts build up in predictable ways to accomplish big things. The complexity is spread out and minimized. The traditional Unix way of doing things is definitely very outdated though. A modern Unix system is like a 100 story skyscraper with the bottom 20 floors nearly abandoned.
Kubernetes and its users would probably be happier if it was used to manage a completely different operating system. In the end, Kubernetes is trying to impose a semi-distributed model of computation on a very NOT distributed operating system to the detriment of system complexity, maintainability, and security.
I agree that universal protocols capable of handling these things are definitely useful. This is why the authors of Unix moved away from communication and protocols that only function on a single system when they were developing Plan 9 and developed the Plan 9 Filesystem Protocol as the universal system "bus" protocol capable of working over networks and on the same physical system. I don't bring this up to be an evangelist. I just want to emphasize that there are alternative ways of doing things. 9P is much simpler and more elegant than HTTP. Also, many of the people who worked on Plan 9 ended up working for Google and having some influence over the design of things there.
A filesystem does not exclusively mean an on-disk representation of a tree of files with a single physical point of origin. A filesystem can be just as "highly available" and distributed as any other way of representing resources of a system if not more so because of its abstractness. Also, you're "disappointed" in me? Lmao
And how do you manage containers? With bespoke tools and infrastructure removed from the file abstraction. Which is another way Kubernetes is removed from the Unix way of doing things. Unless I'm mistaken, it's been a long time since I touched Kubernetes.
It's not a preconception. They engaged with your way of doing things and didn't like it.
By what standard? The standard of you and your employer? In general, you seem to be under the impression that the conventional hegemonic corporate "cloud" way of doing things is the only correct way and that everyone else is unskilled and not flexible.
I'm not saying that this approach doesn't have merits, just that you should be more open-minded and not judge everyone else seeking a different path to the conventional model of cloud/distributed computing as naive, unskilled people making "bad-faith arguments".
This has always felt untrue to me. The command line has always been simple parts. However we cannot argue that this applies to all Unix-like systems: The monolithic Linux kernel, Kerberos, httpd, SAMBA, X windowing, heck even OpenSSL. There's many examples of tooling built on top of Unix systems that don't follow that philosophy.
Depends on what you mean. "Everything is a file"? Sure, that metaphor can be put to rest. "Low coupling, high cohesion"? That's even more valid now for cloud architectures. You cannot scale a monolith efficiently these days.
Kubernetes is more complex than a single Unix system. It is less complex than manually configuring multiple systems to give the same benefits of Kubernetes in terms of automatic reconciliation, failure recovery, and declarative configuration. This is because those three are first class citizens in Kubernetes, whereas they're just afterthoughts in traditional systems. This also makes Kubernetes much more maintainable and secure. Every workload is containerized, every workload has predeclared conditions under which it should run. If it drifts out of those parameters Kubernetes automatically corrects that (when it comes to reconciliation) and/or blocks the undesirable behaviour (security). And Kubernetes keeps an audit trail for its actions, something that again in Unix land is an optional feature.
If you work with the Kubernetes model then you spend 10% more time setting things up and 90% less time maintaining things.
It also has negligible adoption compared to HTTP. And unless it provides an order of magnitude advantage over HTTP, then it's going to be unlikely that developers will use it. Consider git vs mercurial. Is the latter better than git? Almost certainly. Is it 10x better? No, and that's why it finds it hard to gain traction against git.
Even an online filesystem does not guarantee high availability. If I want highly available data I still need to have replication, leader election, load balancing, failure detection, traffic routing, and geographic distribution. You don't do those in the filesystem layer, you do them in the application layer.
Nice ad hominem. I guess it's rules for thee, but not for me.
So what's the problem? Didn't you just say that the Unix way of doing things is outdated? Let the CSI plugin handle the filesystem side if things, and let Kubernetes focus on the workload scheduling and reconciliation.
Dismissal based on flawed anecdote is preconception.
No. I'm not married to the "cloud" way of doing things. But if someone comes to me and says "Hey boblin, we want to implement something on system foo, can you help us?" and I am not used to doing things the foo way I will say "I'm not familiar with it but let's talk about your requirements, and why you chose foo" instead of "foo is for bureaucrats, I don't want to use it". I'd rather hire an open-mined junior than a gray-bearded Unix wizard that dismisses anything unfamilar. And I will also be the first person to reject use cases for Kubernetes when they do not make sense.
There are scenarios where cloud compute just does not make sense, like HPC. If the author had led with something like that, then they would have made a better argument. But instead they went for
,
, and
It's hard to not take that as bad faith.
I can see why you would come to think that if all you've been exposed to is Linux and its orbiting ecosystem. I agree with you that modern Unix has failed to live up to its ideals. Even its creators began to see its limitations in the late 80s and began to develop a whole new system from scratch.
That was never true in the first place. Very few things under Unix are actually represented as files (though credit to Linux for pursuing this idea in kernel-space more than most). But Plan 9 shows us this metaphor is worth expanding and exploring in how it can accomplish being a reliable, performant distributed operating system with a fraction of the code required by other systems.
My point is Kubernetes is a hack (a useful hack!) to synchronize multiple separate, different systems in certain ways. It cannot provide anything close to something like a single system image and it can't bridge the discrete model of computation that Unix assumes.
All these features require a lot of code and complexity to maintain (latest info I can find is almost 2 million as of 2018). Ideally, Kubernetes is capable of what you said, in the same way that ideally programs can't violate Unix filesystem DAC or other user permissions but in practice every line of code is another opportunity for something to go wrong...
Just because something has more security features doesn't mean it's actually secure. Or that it's maintainable without a company with thousands of engineers and tons of money maintaining for you. Keeping you in a dependent relationship.
So? I don't expect many of these ideas will be adopted in the mainstream under the monopoly-capitalist market system. It's way more profitable to keep selling support to manage sprawling and complex systems that require armies of software engineers to upkeep. I think if state investment or public research in general becomes relevant again maybe these ideas will be investigated and adopted for their technical merit.
"Highly available" is carrying a lot of weight there lol. If we can move some of these qualities into a filesystem layer (which is a userspace application on some systems) and get these benefits for free for all data, why shouldn't we? The filesystem layer and application layer are not 2 fundamentally separate unrelated parts of a whole.
Lol, stop being condescending and I won't respond in kind.
I think the reason the Unix way of doing things is outdated is cuz it didn't go far enough!
What? lol
It's not a flawed anecdote or a preconception. They had their own personal experience with a cloud tool and didn't like it.
You can't
someone into liking something.
I'm not a gray-bearded Unix wizard and I'm not dismissing these tools because they're unfamiliar. I have technical criticism of them and their approach. I think the OP feels the same way.
The assumption among certain computer touchers is that you can't use Kubernetes or "cloud" tools and not come away loving them. So if someone doesn't like them they must not really understand them!
They probably could've said it nicer. It's still no excuse to dismiss criticism because you didn't like the tone.
I think Kubernetes has its uses, for now. But it's still a fundamentally limited and harmful (because of its monopolistic maintainers/creators) way to do a kind of distributed computing. I don't think anyone is coming for you to take your Kubernetes though...
Kubernetes is not intended to provide anything like a single system image. It's a workload orchestration system, not an operating system. Given a compatible interface (a runtime) Kubernetes can in theory distribute workloads to any OS.
I'm not going to argue that Kubernetes is not complex. But as I stated previously Kubernetes as a bespoke ecosystem is less complex than configuring the same features with decoupled systems. The requirements for an orchestrator and the challenges (technical, security, human, etc) to manage said orchestrator are higher. All else being equal, Kubernetes has implemented this in a very lean way, delegating networking, storage, and runtime to pluggable providers on the left, and delegating non-basic workload aspects to operators on the right. It's this extensibility that makes it both popular with operators and makes it appear daunting to a layperson. And going back to security, is has provably shown to have a reduced attack surface when managed by a competent operator.
So you're... what, dismissing HTTP because it has been adopted by capitalist market systems? Are you going to dismiss the Fediverse for using HTTP? What about widely adopted protocols? DNS, BGP, IPv4/6, etc?
How about we bring this part of the discussion back to the roots? You said that HTTP and REST as communication protocols seemed strange to you because Unix has other primitives. I pointed out that those primitives do not address many modern client-server communication requirements. You did not refute that, but you said, and I paraphrase "9P did it better". I refrain from commenting on that because there's no comparative implementation of complex Internet-based systems in 9P. I did state though that even if 9P is superior, as you claim, it did not win out in the end. There's plenty of precedents for this: Betamax-VHS, git-mercurial, etc.
(My emphasis) It's not free though. There's an overhead for doing this, and you end up doing things in-filesystem that have no business being there.
*Ahem*:
That is not an experience, it's a provably wrong statement.
That's a very weird assumption, and it's the first time I've heard it. Can you provide a source? Because in my experience the opposite is the case - there's no community more critical of Kubernetes' flaws than their developers/users themselves.
I dismissed the criticism because it makes an appeal to pathos, not to logos. Like I said, there's plenty of valid technical criticisms of Kubernetes, and even an argument on the basis of ethics (like you're making) is more engaging.
No my Kubernetes. I use it because it's academically interesting, and because it does the tasks it is meant to do better than most alternatives. But if CNCF were to implode today and Kubernetes became no longer practical to use then I would just pivot to another system.
I'm not going to argue whether it's a harmful way of doing distributed computing based on their maintainers/pedrigee. That's a longer philosophical discussion than I suspect neither you or I have time for.