Is it time to put your pet Kubernetes down?


Chris Nesbitt-Smith

UK Gov | esynergy | Control Plane | LearnK8s | lots of open source


Chris Nesbitt-Smith

  • Learnk8s & Control Plane Instructor + Consultant
  • esynergy - Digital Transformation Consultant
  • Crown Prosecution Service (UK gov) - Consultant
  • Opensource

Reminder what is Pets vs Cattle?


The before times โณ


2023(?) โŒ›๏ธ

โ˜ธ๏ธ Kubernetes โ˜ธ๏ธ

"duh, we're doing Kubernetes"


โ˜ธ๏ธ Kubernetes: Nodes (naming)

$ kubectl get nodes
NAME                                         STATUS   ROLES    AGE   VERSION   Ready    <none>   24h   v1.21.5-eks-9017834    Ready    <none>   24h   v1.21.5-eks-9017834

โ˜ธ๏ธ Kubernetes: Pods (naming)

$ kubectl get pods -A
NAMESPACE           NAME                                                  READY   STATUS    RESTARTS   AGE
cert-manager        cert-manager-6d99c7965c-c9q92                         1/1     Running   0          24h
cert-manager        cert-manager-cainjector-748dc889c5-ljv8c              1/1     Running   0          24h
cert-manager        cert-manager-webhook-5b679f47d6-wnt2f                 1/1     Running   0          24h
kube-system         aws-node-7b7q4                                        1/1     Running   0          24h
kube-system         aws-node-vwr5m                                        1/1     Running   0          24h
kube-system         calico-node-jfndm                                     1/1     Running   0          24h
kube-system         calico-node-zhzsf                                     1/1     Running   0          24h
kube-system         calico-typha-7dd5d4b984-p52gx                         1/1     Running   0          24h
kube-system         calico-typha-horizontal-autoscaler-767b5c958c-w6pjt   1/1     Running   0          24h
kube-system         cluster-autoscaler-6c8dc687c6-pts7q                   1/1     Running   1          24h
kube-system         coredns-65ccb76b7c-8pqj6                              1/1     Running   0          24h
kube-system         coredns-65ccb76b7c-dd48d                              1/1     Running   0          24h
kube-system         kube-proxy-5vqz2                                      1/1     Running   0          24h
kube-system         kube-proxy-zlh5k                                      1/1     Running   0          24h
kube-system         metrics-server-977777f66-mvr56                        1/1     Running   0          24h
nginx-ingress       ingress-controller-5b47bfdf66-c2xj8                   1/1     Running   0          24h
nginx-ingress       ingress-controller-5b47bfdf66-g94xw                   1/1     Running   0          24h
external-dns        external-dns-689dc89999-s6mjz                         1/1     Running   0          24h

โ˜ธ๏ธ Kubernetes: Pods (checks)

    path: /healthz
    port: http


Don't look ๐Ÿ†™

eksctl create cluster what?



helm install cert-manager jetstack/cert-manager
helm install external-dns external-dns/external-dns
helm install nginx-ingress nginx-stable/nginx-ingress
helm install istiod istio/istiod



  • โ˜ธ๏ธ
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  • โ˜ธ๏ธ team[1-10]
  • โ˜ธ๏ธ team[1-10]
  • โ˜ธ๏ธ team[1-10]
  • โ˜ธ๏ธ team[1-10]
  • โ˜ธ๏ธ team[1-10]



๐Ÿ“† Day 2






















I โค๏ธ ๐Ÿฆ


Keep It Stupid Simple


Keep It Simple, Stupid


๐Ÿถ๐Ÿ”ซ ?


๐Ÿ™ Thanks ๐Ÿ™


Chris Nesbitt-Smith


Chris Nesbitt-Smith

Hello! Imagine a thing with human faces, what a treat, I get to stand up, not worry about being on mute, use my clicker and everything!

So, to kick things off my name is Chris Nesbitt-Smith, I'm based in London and currently work with some well known brands like learnk8s, control plane, esynergy and various bits of UK Government I'm also a tinkerer of open source stuff. I've using and abusing Kubernetes in production since it was 0.4, believe me when I say its been a journey! I've definitely got the scars to show for it. We should hopefully have time for questions and heckles at the end, if not come find me afterwards.

The history of the pets vs cattle terminology is muddy, most link to a presentation Bill Baker from Microsoft made in 2006 around scaling SQL server.

Way back then in the before times, we called ourselves sysadmins and treated our servers like pets

For example Bob the mail server. If Bob goes down, itโ€™s all hands to the pumps. The CEO canโ€™t get his email and itโ€™s the end of the world. We do some incantations, make some sacrifices at an alter and resuscitate Bob bringing him back from the dead

Crisis averted, cue the applause and accolades for our valiant sysadmins who stayed up late into the night

In the new world however, servers are numbered or maybe uuids, like cattle in a herd.

For example, www001 to www100. When one server goes down, itโ€™s taken out back, shot, and replaced on the line.

Why am I telling you this rather morbid story? Kubernetes deals with that right? and saves us from the tyranny

And you're right, it does. All you're computers are called nodes and abstracted and given arbitrary names, autoscaling groups and such will automatically detect the sick in your flock, take them out, and bring a replacement in. all while seamlessly (ish) rescheduling the workload that was on the failed computer

And Kubernetes takes that a step further, your workload also has unique names

Like the physical servers your workload failures can be detected, and replaced seamlessly

So wheres the pet?


Whats the first thing we do with a brand new Kubernetes cluster?

Hint: it's not deploying your application or anything the business cares about

Look familiar? yeah, we had to do a load of 'things' just to make this cluster able to start running our workloads

And it's worth noting that with a trend towards more and more features being being 'out of tree' that is to say they're optional add-ons and don't ship with core Kubernetes. Examples of this are things like flex volumes, policy and basically all the Kubernetes sig projects that many find essential is only exasperating this issue

<click> That might work for when you've got a single cluster<click> But what about when you've got dev <click> integration <click> staging <click> qa that your app needs to run on

Or worse, when you need separation between your teams or products

Maybe you've automated that, bash, ansible, terraform, whatever you like, cool good on you

However you'll find it won't be long before theres an updated version perhaps patching a vulnerability you care about and you may be stuck trying to test every single app across your estate

This is what we're calling day 2 operations, we used to call it BAU or business as usual, and it's where reality catches up with our idealistic good intentions

You'll quickly find that clusters are running various versions, given the rate of change in the community its unrealistic to run :latest everywhere confidently without breaking production and disrupting your operational teams.

Permutations of seemingly common tool choices, some teams might use kong, others nginx, another apache, all for good reasons I'm sure

Seemingly infinite possibilities across the estate emerge

Sad times

Congratulations, you're now the proud owner of a pet shop, or if you managed to automate the creation

You can call it a pet factory, but it's a headache

So what, how does this hurt you might ask?

Maybe you like pets?

Well, presuming of course you're in cloud, your world could roughly be summarized into tiers Apps, well these are things that your board room know about, and can probably name, so think your public website, shopping cart system, customer service apps, online chat interfaces, email system etc. These are all implicitly providing some value in of themselves to your end customers.

Infrastructure, with cloud this is all commodity thankfully, the days where anyone in your business caring about the challenges of physically racking up hardware, not overloading the weight in the cabinet, taking pride in how well they've routed cables have hopefully passed; and you're consuming infrastructure, hopefully you've codified this but even if you're in to ClickOps, making sure its running is not your problem. No one in your business is concerned with hardware failures, patching routers every-time theres a critical vulnerability, testing the UPS and the generators regularly, upgrading the HVAC when you add more servers.

"YAWN-orarma" as my 16 year old would say and curse me for repeating. Your interactions with any of this is a few clicks or lines of code and some infra is available to you with an SLA attached to it.

If only the story ended there

But sandwiched between those is a grey layer, of all the operational enablers, its where your 'devops' or 'SRE' team live. So think log aggregation, certificate issuers, security policies, monitoring, service mesh and others. These are things you do because of all sorts of reasons ranging from risk mitigation to emotion and technically unqualified opinion or just without foresight of what was round the corner in 6 months.

Let's just make the leap and assume for a minute you are more technically competent than your goliath multi-billion dollar cloud vendor

You've completely negated many of the benefits of going to cloud in the first place by ripping up the shared responsibility model All of this while technically fascinating for people like me to stand and

stroke my beard at. This is delivering absolutely zero business value, unless of course your business is building or training on those products.

and who'd want to get into that business!

And thats not all! Recruitment...

You might think you want a devops right? oh no wait, devops with Kubernetes experience, maybe a CKA? oh yeah, its on AWS, and we use linkerd and in some places istio, no not the current version, or even the same version everywhere. a mix of pod security policy, kyverno and OPA for policy, some terraform, helm, jenkins, github action soup going on, all in a mono-repo apart from all that stuff that isn't.

We're well outside the remit of commodity skills and back to hunting unicorns.

Sure you'll find some victims. sorry...

I mean candidates; that you'll hire, well now you've got one hell of an onboarding issue before they can do anything useful and help your business move forwards faster than it did without them.

And if you hired smart people they'll come with experience and their own opinions of what worked for them before, so your landscape gets bigger and bigger and more complex and diverse

I did some googling, this is what the CNCF landscape looked way back in 2017.

Choices, right? choices and logos as far as the eye can see.

Have you seen it recently?

This has got a bit out of hand, I'd say someone aught to have a word but I suspect that'd just make things worse by adding yet another thing

and don't get me started on operators, nice idea but betray any ideals of immutability, crazy levels of abstraction for..

and have you seen the crazy of mutating admission controllers

If you're really mad, you can nest these things, with operators that create crds for other operators that are all mutated, heaven forbid someone bumps the version of anything?

All no doubt held together with sticky tape, chewing gum, glue, pipe cleaners, thoughts and prayers and


a string based templating engine where any community module has to eventually expose every parameter in every object file abstracted by a glorified string replace

So now I've got to have in my head all the complexities of a linux/windows host, how the container runtime works, the software defined network and storage, the hypervisor, before the container, the scheduler, controllers, auth and policy and mutating policy in the cluster.

before I worry about how someone in the nested helm chart mess of hell, has mapped the replica count of one of the deployments to a string called db replica count, and how that has changed in a new version of a dependency not following semver to "database_replica_count", so instead of having my expected 3 I've now only got 1

when I could have just written a yaml patch for the replica count in the deployment object of the database resource using stable API versioning with schema validation for free, ahhh

the kids doing Kubernetes don't seem to have learned from the past

don't get me wrong, I love the open source community with all my heart, its so important

and its simply not possible to do anything without it sorry, not sorry, yes as a sidebar, every talk this year is contractually required to reference log4j, this is my slide, deal with, its not relevant, it can come out in a couple of months

everything literally everything that exists around us depends upon it, and the community is brilliant, at building some truly remarkable very high quality things, but we must accept that

the open source community

is awful at packaging things up

in this way for consumption, introducing needless abstractions

but enough of that, I'm definitely going to hell now

happy place chris, happy place where was I, right yes so through all of this

I can't possibly think of a faster way to go from enthusiastic engineers playing with new exciting tech

To deeply unhappy ones trying to fix something at 4am

and before they can do anything meaningful they've got an orienteering exercise to switch mental context to whatever the intended permutation of things it is they're looking at.

Meanwhile your business value delivering apps are offline, or worse at breach

Rewind a minute we didn't want any of these things, how did we get here? What can we do about it?

honestly? bin it all

kill it with fire

and then Learn to

love vanilla, vanilla is great, and delicious too

anyone remember KISS?

no, not the band

Keep it stupid simple

or Keep it simple, stupid

and embrace the shared responsibility model on offer, and make your cloud vendors do more than just provide compute, turns out as it happens, they're not that bad at it

I'm not daft I know it's not sexy and exciting, you might even find recruitment harder if you're used to

hunting magpies who follow the shiny and don't like boring stuff that works

So, to answer the question posed from the title of my talk, is it time you put your pet Kubernetes cluster down?

Yes, yes is it. And in the immortal words of s-club 7 if you can

bring it on back immutably from code, all without anyone noticing (I'm referring to the original version of the lyrics)

Then maybe just maybe it can earn the right to stay to

die another day

I've been Chris Nesbitt-Smith, thank you again for joining me today and enduring my self loathing. Like subscribe whatever the kids do these days on LinkedIn, Github whatever and you can be assured there'll be no spam or much content at all since I'm awful at self promotion especially on social media. just points at my LinkedIn. contains this and other talks, they're all open source.

Questions are very welcome on this or anything else, I'll hold the stage as long as I'm allowed, or find me afterwards, this grumpy old man needs to go find somewhere to sit down soon <Change to last slide>