k8s is king

k8s_learning_path.md

Get familiar with the base concepts

Doesn't need a running cluster! Install podman and kubectl.

• kubectl
  • Don't write it down as a simple tool to interact with clusters. kubectl can create all sorts of resources like secrets, pods, deployments etc. Great for learning.
  • kubectl run (kubectl run -i --tty --rm debug --image=registry.opensuse.org/opensuse/tumbleweed --restart=Never -- bash)
  • kubectl exec (kubectl exec -it -n default debug -- bash)
  • kubectl create (kubectl create deployment test --image registry.adathor.com/opensuse/tumbleweed --replicas 3 --dry-run=client -o yaml)
  • kubectl logs
  • kubectl get
  • kubectl apply
  • kubectl describe
  • etc etc etc
• etcd
• pods -labels and annotations
  • securityContext
  • env
    • in pod config
    • reference from ConfigMap (CM)
    • reference from Secrets
  • resources
    • cpu and ram
    • limits and requests
  • imagePullSecret if using a private registry/repo
• ConfigMaps
• Secrets
• Services

Going deeper

Still doesn't need a cluster

• deployments
  • replicas
• PersistentVolumeClaims
• Mounts kinda ties back to pods
• Volumes

Get a cluster

Local stuff for dev/learning:

• KIND

• Minikube

• Pick a managed kubernetes service

  • GKE
  • LKE
  • EKS
  • AKS

• StatefullSets and why should we avoid these (ideally)

• Ingress - Install ingress-nginx or traefik,

• LoadBalancer

• Custom resource definition

• Kubernetes operators

Tooling - Can jump into getting to know these at any point

Cluster side:

• ArgoCD- continous delivery (GitOps)
• ArgoCD image updater - use the sha, not the tags for deploying images
• cert-manager - sweet, sweet tls
• istio - networking, a certain type of journey all by its own. Super handy, get a course on Udemy for it.
• kyverno - policy management

Cli:

• kustomize
  • manifest management/templating, super great if you don't want to fork and downstream maintain helm packages
• helm
  • manifest templating, a pain to write for complex deplyoments, not ideal if you need to do something that requires change to the helm package
• k9s a tui cluster manager, super handy. No need for abstractions like Rancher or Lens.
• kuebctl
• kubectx if managing multiple clusters
• cosign - make your images verifyable by signing them, reject them if the signature doesn't match.

Ideal for the underlying infrastructure management. Not exactly a strict k8s requirement, should have these from the get go even for regular VMs/metal/VPS management:

• Ansible
• Terraform

Basics training video