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Future of Kubernetes

Storage

  • Storage and stateful workloads are harder in all sytems
  • Containers make it both harder and easier than before
  • StatefulSets is a new resource type, making Pods more sticky

  • Avoid stateful workloads for fist few deployments until you're good at the basics

    • Use db-as-a-service whenever you can

Volumes

  • Creating and connecting Volumes: 2 types

  • Volumes

    • Tied to lifecycle of a pod
    • All containers in a single Pod can share them

  • PersistentVolumes

    • Created at the cluster level, outlives a Pod
    • Seperates storage config from Pod using it
    • Multiple Pods can share them
  • CSI plugins are the new way to connect to storage

Ingress Controller

  • None of our Service types work at OSI Layer 7 (HTTP)
  • How do we route outside connections based on hostname or URL?
  • Incress Controllers (optional) do this with 3rd proxy parties
  • Nginx is popular, Traefik, HAProxy, F5, Envoy, Istio, etc.
  • Implementation is specific to Controller chosen

Custom Resources

CRD's and The Operator Pattern

  • YOu can add 3rd party Resources and Controllers
  • THis extends Kubernetes API and CLI
  • A pattern is starting to emerge of using these together
  • Operator: automate deployment and management of complex apps
  • e.g. Databases, monitoring tools, backups, and custom ingresses

Higher Deployment Abstractions

  • All our kubectl commands just talk to the Kubernets API
  • Kubernetes has limited built-in templating, versioning, tracking, and management of your apps
  • There are now over 60 3rd party tools to do that , but many are defunct
  • Helm is the most popular
  • "Compose on Kubernetes" comes with Docker Desktop
  • Remember these are optional, and your distro may havbe a preference
  • Most distros support Helm

Templating YAML

  • Many of the deployment tools have templating options
  • You'll need a solution as the number of environments/apps grow
  • Helm was the first "winner" in this space, but can be complex
  • Official Kustomize feature works out-of-the-box (as of 1.14)
  • docker app and compose-on-kubernetes are Docker's way

Kubernetes Dashboard

  • Default GUI for "upstream" Kubernetes

    • github.com/Kubernetes/dashboard
  • Some distributions have their own GUI (Rancher, Docker Ent, OpenShift)
  • Clouds dont have it by default
  • Let's you view resources and upload YAML
  • Safety first!

Namespaces and Context

  • Namespaces limit scope, aka "virtual clusters"
  • Not related to Docker/Linux namespaces
  • Won't need them in small clusters

  • There are some built-in, to hide system stuff from kubectl "users"

    • kubectl get namespaces
    • kubectl get all --all-namespaces
  • Context changes kubectl cluster and namespace
  • See ~/.kube/config file
  • kubectl config get-contexts
  • kubectl config set*

Future of Kubernetes

  • More focus on stability and security

    • 1.14, 1.15, largely dull releases (good thing)
    • Recent security audit has created backlog
  • Clearing away deprecated features like kubectl run generators
  • Improving features like server-side dry-run
  • More and improved Operators
  • Helm 3.0 (easier deployment, chart repos, libs)
  • More declarative-style features
  • Better Windows Server support
  • More edge cases, kubeadm HA clusters
  • Kubernetes has become "differencing and scheduling engin backbone" for so many new projects
  • Knative - Serverless workloads on Kubernetes
  • k3s - mini, simple Kubernetes
  • k3OS - Minimal Linux OS for k3s
  • Service Mesh - New layer in distributed app traffic for better control, security and monitoring