rust.md

rust.md

options	title	author
implicit_slide_ends true	Kubernetes meets Rust	Shawn Wang @ TOOCON 2402

Outline

• What is Kubernetes?
  • Some Rust Kubernetes utilities
• Why Rust is good for Kubernetes? (kube.rs)
• Rust for other parts of Kubernetes.

---

source

• https://gist.github.com/shawn111/ebebfcf7e0bbd4a7ac9e17adefd625cc
• presenterm

kubernetes overview

• k8s - container orchestration engine
  • automating deployment / scaling
  • management containerized applications

      ┌─────────────────────────┐ ┌────┬────────────┐
      │   ┌────┐  Control Plan  │ │Node│kube-proxy┌─┴─────┐
      │   │etcd│                │ │   ┌┴──────┬─┬─│Network│
─────┐│   └────┘    ┌───────┐   │ │   │kubelet│ │ └────.──┘
Admin├┼─────────────►  Api  ◄───┼┐└───┴──┬────┴─┘    .. 
kubectl             └───────┘   │└────┬──┴┐       ┌─.───
─────┘│   ┌────────────────┐    │ ┌───┴──┐│       │Users
      │   │ kube-scheduler │    │ │ Node ││       └─────
      │┌──┴────────────────┴───┐│ └───┬──┴┴──┐
      ││kube-controller-manager││     │ Node │
      └┴───────────────────────┴┘     └──────┘

Componenents

Admin

• kubectl
• others
  • helm
  • kdash / k9s

Control Plane

• kube-scheduler - assigns Pods to Nodes
• kube-controller-manager
• etcd
• kube-api

Node

• kubelet - kube agent
  • cri - contianerd / cri-o
  • cni
• kube-proxy

k8s quick start

• prepare docker or podman
  • apt install podman
• kind
  • kind create cluster
• kubectl
• prepare kubecfg
  • $KUBECONFIG
  • kubectl config view
  • kubectl config view --raw

kind create cluster -n toocon

podman ps

kubectl get pods -A

API / Objects In Kubernetes

• Object spec and status

• API / Resource

• API Group

• watch

• kubectl / restful

❯ k get pod nginx-0 -o yaml
apiVersion: v1
kind: Pod
metadata:
  labels:
    app: nginx
  name: nginx-0
  namespace: default
spec:
  containers:
  - image: nginx:1.16.1
status:
  conditions:
...

Example of Operator/Controller

application

controller

reconciler

CRD

                    ┌──────────┐
               ┌────┤controller├──────┐
               │    └────▲─────┘      │
               │         │      schedule object
             watch    result          │
┌────────┐     │         │       ┌────▼─────┐
│kubectl │     │         └───────┤reconciler│
└───┬────┘     │                 └────┬─────┘
    │          │                   update
    │     ┌────▼────┐              `  │
    └─────►kube api ◄─────────────────┘
          └─────────┘

Why Rust

• Concurrency
• No garbage collection.
• memory safe
• performance
• cargo
• cli
• kube.rs
• kernel / M$ / ... love rust
• ...

kube.rs

• core Rust ecosystem for building applications against Kubernetes.
• accepted to CNCF on November 16, 2021 at the Sandbox maturity level ...

kube

• 5 crates

kube-core

Core traits and types necessary for interacting with the kubernetes API.

kube-derive < kube-core

for managing Custom Resource Definitions

kube-client < kube-core

kube::client and kube::config modules.

kube-runtime < kube-client

Common components for building Kubernetes operators

KDash

 KDash - A simple Kubernetes dashboard    v0.6.0 with ♥ in Rust  
┌───────────────────────────────────────────────────────────────┐
│ Active Context <A>│All Contexts <C>│Utilization <U><←→> switch│
└───────────────────────────────────────────────────────────────┘
┌ Namespaces <n> (all: <a>) ────────┐┌ Context┐┌ CLI Info (filte┐
│   Name                   Status   ││CPU:    ││kubectl  v1.29.0│
│=> kube-insider           Active   ││0% ━━━━━││kubectl  v1.29.1│
└───────────────────────────────────┘└────────┘└────────────────┘
┌ Resources ────────────────────────────────────────────────────┐
│ Pods <1>│ Services <2>│ Nodes <3>│ ConfigMaps <4>│ StatefulSe │
│                                                               │
│       ┌ Select Resource ───────────────────────────────┐      │
│       │   ResourceQuota                                │      │
│       │=> Tunnel                                       │      │
│       │   ValidatingWebhookConfiguration               │      │
│       └────────────────────────────────────────────────┘      │
└───────────────────────────────────────────────────────────────┘

k8s-insider - an operator help to access you kubernetes cluster network

k8s-insider install --pod-cidr 10.244.0.0/16
k8s-insider create network
k8s-insider connect

❯ kubectl get networks.k8s-insider.dev -A
NAMESPACE      NAME      AGE
kube-insider   default   6h51m

❯ kubectl get tunnels.k8s-insider.dev -A
NAMESPACE      NAME              AGE
kube-insider   default-bjk40r   6h49m
kubectl get services -n kube-insider
NAME     TYPE     CLUSTER-IP   EXTERNAL-IP PORT(S)        AGE
k8s-... NodePort  10.96.153.40 <none>      1234:31237/UDP 54m

my shell env for k8s

• starship - cross shell prompt
• kubie kbs
• kdash
• k8s-insider

sidecar

• Linkerd linkerd2 (Linkerd is a service mesh for Kubernetes.)
  • https://github.com/olix0r/kubert
  • CNCF 2023: Alex Leong, Five Years of Cloud Native Rust.
• Istio ztunnel

service operators

• Stackable https://github.com/orgs/stackabletech/repositories
• Tembo Stacks: Making Postgres the Everything Database https://tembo.io/

krustlet/krator

Leveraging State Machines to Build Operators in Rust - Kevin Flansburg, Moose Consulting

utils

• mirrord https://mirrord.dev/
• kubectl plugins
  • kubectl-watch
  • krew-wasm Qovery - Enable Developers Self-Service: Terraform, Helm, Kubectl, and Docker Shulker - The modern way of putting Minecraft in boxes

• container related projects
  • youki
  • https://github.com/containers/conmon-rs (podman)
• wasmtime
• rust-vmm

helm related

conmon-rs

hello

metrics -> prometheus telemetry -> OpenTelemetry

sidecar

• Linkerd

kubectl plugins

Rust for other parts of Kubernetes.

• container / vmm
• wasm

k8sfwd k8s-insider

kubetui kdash kubectl-view-allocations

kubeconfig-bikeshed / kbs kubesess kubie

krew-wasm krew-wasm-plugin-sdk-rust

ksnotify