Unsung Hero of the Cloud Native Revolution
Container Linux Then and Now

KubeCon NA 2022

Vincent Batts

Howdy 👋

$> whoami

vbatts

$> id -Gn

devel msft flatcar kinvolk redhat oci appc docker golang slackware ruby

Container Linux!

• ●Cloud Native! 

• ●Minimal Footprint! 

• ●IKEA vs. Artisanal 

• ●Atomic updates! 

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But, what is “a Linux”?

• ●Well, actually it’s GNU/Linux … 

   

• ●What makes it “what people and tooling expect?” 

Is this a Linux?

• ●syscalls, ioctls, fcntls? 

• ●libc? 

• ●Kernel CONFIG_’s? 

• ●Config (/etc or CM tooling) 

• ●Early boot provisioning? (ignition or cloud-init) ((secrets??)) 

• ●Host services? (unit files and dbus?) 😩 

• ●NVR of software 

A brief history

• ●Read only? 

  • –Knoppix (2000) – a first of the “live” from CD Linuxes 

• ●Minimal? 

  • –Damn Small Linux (2005) ~50Mb 

• ●Isolation? 

  • –mountns (2002) 

• ●“Userspace” 

  • –An ongoing swarm of iteration and improvements and sprawl 

A brief history

• ●2008 LXC is launched 

• ●2013 CoreOS releases the first “Container Linux” 

  • –based on the ChromiumOS created for Chromebooks 

  • –Gentoo is the upstream 

• ●2013 dotCloud releases Docker 

• ●2014 Kubernetes is launched 

• ●Since then: Atomic; Flatcar; Talos; FedoraCoreOS (RHEL and CentOS too); bottlerocket; k3os; openSUSE Micro; LinuxKit; gardenlinux; and I’m sure others ... 

(other history talks at github.com/vbatts/talks)

Common Challenges

• ●Do you know when something becomes artisanal? 

• ●Package management 

  • –Trust 

  • –Proofs 

  • –Determinism (scriptlets; ordering; file system API’s) 

• ●Who says a a reboot is needed? How? 

• ●“Let’s innovate and think about how to migrate later!” 

• ●“If folks should use my approach if they want things to work together!”  

   

Common Challenges

• ●“is this change/rollout deterministic?” 

• ●When you deploy “A Kubernetes”, that is not a definitive, standard thing. 

  • –Every extension, runtime, plugin, and even config field can have implicit and explicit variations needed. 

Don’t get me wrong

• ●Packagers and Upstreams are critical 

• ●The kernel and OS [interfaces] you use matter 

• ●You end users and admins/ops/architects actively don’t care about your epiphany if you’ve made their life harder for no reason 

• ●Everyone wants their precious to be the winner … 

Where are we now?

• ●It depends... 

• ●Compartmentalizing our frustration 🥺 

• ●We’ve all suffered these pains, individually and collectively 

• ●Renewed interest in defining and establishing the common OS interfaces 

  • –#kube-operating-systems-dev (k8s slack) 

  • –(beyond kubelet, CRI, CNI, CSI, etc.) 

• ●What is your use-case? Let that drive you, not a marketing pitch 

💚 y’all

• ●Find me online 

  • –Then we can talk like humans 

    • ●Let’s work together