Fringe Division

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Kubernetes ​

Setup ​

bash
# curl -sfL https://get.k3s.io | sh -
curl -sfL https://get.k3s.io | INSTALL_K3S_EXEC="server --disable traefik" sh # so it frees up port 80 and 443

## register a worker node
# get NODE_TOKEN via `cat /var/lib/rancher/k3s/server/node-token`
export K3S_URL=https://myserver:6443
export NODE_TOKEN=
curl -sfL https://get.k3s.io | K3S_URL="$K3S_URL" K3S_TOKEN="$NODE_TOKEN" sh -

# export kubeconfig
k3s kubectl config view --raw # copy this to ~/.kube/config on your local machine

# uninstall
/usr/local/bin/k3s-uninstall.sh

Usage ​

bash
# restart deployment
kubectl rollout restart deploy $DEPLOYMENT_NAME

# trigger jobs manually
kubectl create job --from=cronjob/$CRONJOB_NAME $JOB_NAME -n $NAMESPACE

# referencing service hostname from within cluster
## see: https://stackoverflow.com/a/55650127
`<service.name>.<namespace name>.svc.cluster.local` or `<service.name>.<namespace name>`

# reverse `kubectl apply`
kubectl delete -f <filename>

Distributions ​

  • kairos - Transform your Linux system and preferred Kubernetes distribution into a secure bootable image for your edge devices.

Add-Ons ​

  • Cilium - Cloud Native, eBPF-based Networking, Observability, and Security.
  • Knative - Open-Source Enterprise-level solution to build Serverless and Event Driven Applications.
  • KubeVirt - Building a virtualization API for Kubernetes
  • kserve - Standardized Serverless ML Inference Platform on Kubernetes.
  • kube-green - An operator to reduce CO2 footprint of your clusters

Monitoring & Observability ​

  • Coroot - Coroot is an open-source eBPF-based observability tool that turns telemetry data into actionable insights, helping you identify and resolve application issues quickly.

Cookbook ​

Pulling image from private registry ​

hcl
resource "kubernetes_secret" "harbor_config" {
  for_each = local.namespaces

  metadata {
    name      = "harbor-cfg"
    namespace = each.key
  }

  type = "kubernetes.io/dockerconfigjson"

  data = {
    ".dockerconfigjson" = jsonencode({
      auths = {
        "${var.registry_server}" = {
          "username" = var.registry_username
          "password" = var.registry_password
          "auth"     = base64encode("${var.registry_username}:${var.registry_password}")
        }
      }
    })
  }
}

In deployment specs, add:

yaml
containers:
imagePullSecrets:
  - name: harbor-cfg

Emptying the finalizers for a namespace that will not delete ​

https://fabianlee.org/2022/03/08/kubernetes-emptying-the-finalizers-for-a-namespace-that-will-not-delete/

bash
export NAMESPACE=
kubectl get ns $NAMESPACE -o json | jq '.spec.finalizers = []' | kubectl replace --raw "/api/v1/namespaces/$NAMESPACE/finalize" -f -

Force delete ghost pods ​

bash
kubectl delete pods <pod> --grace-period=0 --force

Local dev Kubernetes setup ​

https://k3d.io/

bash

k3d cluster create mycluster
k3d cluster delete mycluster

Tools ​

  • distroless - 🥑 Language focused docker images, minus the operating system.
  • pluto - A cli tool to help discover deprecated apiVersions in Kubernetes.
  • Kubeshark - Wireshark for Kubernetes.
  • cosign - Container signing.
  • kubetail - Web-based, real-time log viewer for Kubernetes.
  • Falco - Detect security threats in real time.

Resources ​