I’m baffled to see so many anti-k8s sentiments on HN. Is it because most commenters are developers used to services like heroku, fly.io, render.com etc. Or run their apps on VM’s?
Honestly, as it stands, I think we'd be seen as pretty useless craftsmen in any other field due to an unhealthy obsession of our tooling and meta-work - consistently throwing any kind of sensible resource usage out of the window in favor of just getting to work with certain tooling. It's some kind of a "Temporarily embarrassed FAANG engineer" situation.
In the software/tech industry it's common place to just accept that your app can't be down for any amount of time no matter what. No one checked to see how much more it would cost (engineering time & infra costs) to deploy the app so it would be HA, so no one checked to see if it would be worth it.
I blame this logic on the low interest rates for a decade. I could be wrong.
But a lot of companies are building distributed systems purely because they want this ultra-low downtime. Distributed systems are HARD. You get an entire set of problems you don't get otherwise, and the complexity explodes.
Often, in my opinion, this is not justified. Saving a few minutes of downtime in exchange for making your application orders of magnitude more complex is just not worth it.
Distributed systems solve distributed problems. They're overkill if you just want better uptime or crisis recovery. You can do that with a monolith and a database and get 99.99% of the way there. That's good enough.
FAANG engineers made the same mistake, too, even though the analogy implies comparative competency or value.
While nomad can be interesting again it's a single "smallish" vendor pushing an "open" (see debacle with Teraform) source project.
But for some deeper details, I'd suggest checking out the comments in this reddit thread[0] (as well as some of the linked articles therein).
E.g. From a comment by /u/Golden_Age_Fallacy: A great use of Nomad is on reduce the burden of on-boarding a team(s) of developers who are unfamiliar with cloud native deployments / systems(even containers!).
Nomad jobspecs are very simple and straight forward, as compared to the complexity and pure option overload you get in k8s and helm.
From /u/neutralized: It's much easier to use than k8s. Easy to setup, easy to manage, much more shallow learning curve. Nothing super fancy. Just works. I migrated a startup I was at off of a self-managed k8s setup to Nomad a few years ago and they've never looked back.
From /u/esity: My team is currently building out a fully automated nomad cluster service offering internally(fortune 10)
It's super awesome. Easy. Little headache. Integrates with consul and vault. We are literally planning to replace thousands of vms for K8s with nomad. Containers are faster, more resilient and writing hcl is actually fun once you learn it
Now, there is a rather more lengthy comment, by /u/thomasbuchinger, that goes through the pros and cons he experienced in trying Nomad out and his conclusion is that, while he wouldn't discourage anyone from using it, "k3s and a few well-known simple projects give you 80% of Nomands [sic] features. Are as easy to operate, afford you more options in the future and have a ton of documentation/tutorials...available."
There are more comments in the thread and again links to a bunch of blogposts/articles/etc., including one from fly.io that seemed pretty detailed, discussing the Googly origins of both k8s and Nomad (fly.io used Nomad but found that it wasn't the best fit for them, which is also discussed in their post -- actually, I'm going to put the link to their post below[1], since I think it is worthwhile).
Hope all this helps.
[0] https://old.reddit.com/r/devops/comments/11nsxo3/opinions_on...
[1] https://fly.io/blog/carving-the-scheduler-out-of-our-orchest...
I don't want to set up or maintain my own ELK stack, or Prometheus. Or wrestle with CNI plugins. Or Kafka. Or high availability Postgres. Or Argo. Or Helm. Or control plane upgrades. I can get up and running with the AWS equivalent almost immediately, with almost no maintenance, and usually with linear costs starting near zero. I can solve business problems so, so much faster and more efficiently. It's the difference between me being able to blow away expectations and my whole team being quarters behind.
That said, when there is a genuine multi-cloud or on-prem requirement, I wouldn't want to do it with anything other than k8s. And it's probably not as bad if you do actually work at a company big enough to have a lot of skilled engineers that understand k8s--that just hasn't been the case anywhere I've worked.
Because as annoying as getting the prometheus + loki + tempo + promtail stack going on k8s is —- I don’t really believe that writing it from scratch is easier.
* Log aggregation happens out of the box with CloudWatch Logs and CloudWatch Log Insights. It's configurable if you want different behavior
* On ECS, you configure a "service" which describes how many instances of a "task" you want to keep running at a given time. It's the abstraction that handles spinning up new tasks when one fails
* ECS supports ready checks, and (as noted above) integrates with ALB so that requests don't get sent to containers until they pass a readiness check
* Machine maintenance schedules are non-existent if you use ECS / Fargate, or at least they're abstracted from you. As long as your application is built such that it can spin up a new task to replace your old one, it's something that will happen automatically when AWS decommissions the hardware it's running on. If you're using ECS without Fargate, it's as simple as changing the autoscaling group to use a newer AMI. By default, this won't replace all of the old instances, but will use the new AMI when spinning up new instances
But again, though: the biggest selling point is the lack of maintenance / babysitting. If you set up your stack using ECS / Fargate and an ALB five years ago, it's still working, and you've probably done almost nothing to keep it that way.
You might be able to do the same with Kubernetes, but your control plane will be out of date, your OSes will have many missed security updates. Might even need a major version update to the next LTS. Prometheus, Loki, Tempo, Promtail will be behind. Your helm charts will be revisions behind. Newer ones might depend on newer apiVersions that your control plane won't support until you update it. And don't forget to update your CNI plugin across your cluster, too.
It's at least one full time job just keeping all that stuff working and up-to-date. And it takes a lot more know-how than just ECS and ALB.
Most of my managed Kubernetes experience is through Amazon's EKS, and the pain I remember included frustration from the supported Kubernetes versions being behind the upstream versions, lack of visibility for troubleshooting control nodes, and having to explain / understand delays in NIC and EBS appropriation / attachments for pods. Also the ALB ingress controller was something I needed to install and maintain independently (though that may be different now).
Though that was also without us going neck-deep into being vendor agnostic. Using EKS just for the Kubernetes abstractions without trying hard to be vendor agnostic is valid--it's just not what I was comparing above because it was usually that specific business requirement that steered us toward Kubernetes in the first place.
If you ARE using EKS with the intention of keeping as much as possible vendor agnostic, that's also valid, but then now you're including a lot of the stuff I complained about in my other comment: your own metrics stack, your own logging stack, your own alarm stack, your own CNI configuration, etc.
- ALBs -- yeah this is correct. However ALBs have much longer startup/health check times than Envoy/Traefik
- Cloudwatch - this is true, however the "configurable" behavior makes cloudwatch trash out of the box. you get i.e. exceptions split across multiple log entries with the default configure
- ECS tasks - yep, but the failure behavior of tasks is horrible because there're no notifications out of the box (you can configure it)
- Fargate does allow you to avoid maintenance, however it has some very hairy edges like i.e. you can't use any container that expects to know its own ip address on a private vpc without writing a custom script. Networking in general is pretty arcane on Fargate and you're going to have to manually write and maintain the breakages from all this
> You might be able to do the same with Kubernetes, but your control plane will be out of date, your OSes will have many missed security updates. Might even need a major version update to the next LTS. Prometheus, Loki, Tempo, Promtail will be behind. Your helm charts will be revisions behind. Newer ones might depend on newer apiVersions that your control plane won't support until you update it. And don't forget to update your CNI plugin across your cluster, too.
I think maybe you haven't used K8S in years. Karpenter, EKS, + a GitOps (Flux or Argo) makes you get the same machine maintenance feeling as ECS but on K8S without any of the annoyances of dealing with ECS. All your app versions can be pinned or set to follow latest as you prefer. You get rolling updates each time you switch machines (same as ECS, and if you really want to you can run on top of Fargate).
By contrast, if your ECS/Fargate instance fails you haven't mentioned any notifications in your list -- so if you forgot to configure and test that correctly, your ECS could legitimately be stuck on a version of your app code that is 3 years old and you might not know if you haven't inspected the correct part of amazon's arcane interface.
By the way, you're paying per use for all of this.
At the end of the day, I think modern Kubernetes is strictly simpler, cheaper, and better than ECS/Fargate out of the box and has the benefit of not needing to rely on 20 other AWS specific services that each have their own unique ways of failing and running a bill up if you forget to do "that one simple thing everyone who uses this niche service should know".
Sure there are a lot of great feature with k8s which ECS cannot do, but when ECS does satisfy the requirements, it will require less maintenance, no matter what kind of k8s you compare it against to.
Obviously that part's not different from Kubernetes, but here's the part that is: maintenance and upgrades are either completely out of my scope or absolutely minimal. On ECS, it might involve switching to a more recently built AMI every six months or so. AWS is famously good about not making backward incompatible changes to their APIs, so for the most part, things just keep working.
And don't forget you'll need a lot of those AWS skills to run Kubernetes on AWS, too. If you're lucky, you'll get simple use cases working without them. But once PVCs aren't getting mounted, or pods are stuck waiting because you ran out of ENI slots on the box, or requests are timing out somewhere between your ALB and your pods, you're going to be digging into the layer between AWS and Kubernetes to troubleshoot those things.
I run Kubernetes at home for my home lab, and it's not zero maintenance. It takes care and feeding, troubleshooting, and resolution to keep things working over the long term. And that's for my incredibly simple use cases (single node clusters with no shared virtualized network, no virtualized storage, no centralized logs or metrics). I've been in charge of much more involved ones at work and the complexity ceiling is almost unbounded. Running a distributed, scalable container orchestration platform is a lot more involved than piggy backing on ECS (or Lambda).
In some ways, it's nice to see companies move to use mostly open source infrastructure, a lot of it coming from CNCF (https://landscape.cncf.io), ASF and other organizations out there (on top of the random things on github).
There are kata-containers I think, they might solve my angst and make me enjoy k8s
Overall... There's just nothing cool in kubernetes to me. Containers, load balancers, megabytes of yaml -- I've seen it all. Nothing feels interesting enough to try
If you have never dealt with, I have to run these 50 containers plus Nginx/CertBot while figuring out which node is best to run it, yea, I can see you not being thrilled about Kubernetes. For the rest of us though, Kubernetes helps out with that easily.
if there's a kernel vulnerability in something simple (like dirtycow, which was if I remember correctly about pipes) then the attacker will take over your entire 128 core machine and all the hundreds applications there
It's the ecosystem around it which turns things needlessly complex.
Just because you have kubernetes, you don't necessarily need istio, helm, Argo cd, cilium, and whatever half baked stuff is pushed by CNCF yesterday.
For example take a look at helm. Its templating is atrocious, and if I am still correct, it doesn't have a way to order resources properly except hooks. Sometimes resource A (deployment) depends on resource B (some CRD).
The culture around kubernetes dictates you bring in everything pushed by CNCF. And most of these stuff are half baked MVPs.
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The word devops has created expectations that back end developer should be fighting kubernetes if something goes wrong.
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Containerization is done poorly by many orgs, no care about security and image size. That's a rant for another day. I suspect this isn't a big reason for kubernetes hate here.