# Future of Kubernetes

> Markdown source of <https://docs.calebsargeant.com/computing/kubernetes/next-steps/>.

## 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

### Related Projects

- 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