Kubernetes Stuff

#Kubernetes.md

General Kubernetes scripts and snippets

aks-nodes.sh

#!/bin/bash

HELP=false

# Display usage
usage(){
echo "\
aks-nodes.sh - Start or stop all nodes in your AKS cluster
Parameters:
    -n, --name     Name of AKS managed cluster (required)
    -g, --group    Resource group containing AKS managed cluster (required)
    -a, --action   VM action [start, stop]
    [-h]           Show this help text
" | column -t -s ";"
}

# Param handling stuff
OPTS=`getopt -o n:g:a:h --long name:,group:,action:,help -n 'parse-options' -- "$@"`
if [ $? != 0 ] ; then echo "Failed parsing options." >&2 ; usage; exit 1 ; fi
eval set -- "$OPTS"

# Param handling stuff
while true; do
  case "$1" in
    -n | --name ) AKS="$2"; shift; shift;;
    -g | --group ) GROUP="$2"; shift; shift;;
    -a | --action ) ACTION="$2"; shift; shift;;
    -h | --help ) HELP=true; shift ;;
    -- ) shift; break ;;
    * ) break ;;
  esac
done

if [ ${HELP} = true ] ; then
  usage
  exit 0
fi

# Name and group are required params
if [ -z ${GROUP} ] || [ -z ${AKS} ] || [ -z ${ACTION} ] ; then
  usage
  exit 1
fi

# Action must be start or stop
if [[ ! ("$ACTION" == "stop" || "$ACTION" == "start") ]] ; then
  usage
  exit 1
fi

if [ ${ACTION} == "stop" ] ; then
  ACTION="deallocate"
fi

loc=`az resource show -g $GROUP -n $AKS --resource-type Microsoft.ContainerService/managedClusters --query "location" -o tsv`
if [ -z ${loc} ] ; then
  echo "Error. Unable to find AKS cluster '$AKS' in group '$GROUP'"
  exit 0
fi

mcgroup="MC_${GROUP}_${AKS}_${loc}"
echo "Locating VMs in $mcgroup ..."

vmquery=`az vm list -g $mcgroup -o tsv --query "[].name"`
vmlist=$(echo $vmquery | tr " " "\n")

for vm in $vmlist
do
    az vm $ACTION -g $mcgroup -n $vm --no-wait
    echo "Running $ACTION on $vm ..."
done

dash-external.sh

#!/bin/bash

echo "### ❌ Deleting old service and waiting..."
kubectl delete svc dash-external -n kube-system
sleep 120

# CHANGE THIS TO YOUR STATIC IP IN AZURE
lbip="12.34.56.78"
ip=$(curl -s ipinfo.io/ip)
echo "### 🌐 Your public IP has been detected as $ip"

cat > dash.yaml <<- EOM
kind: Service
apiVersion: v1
namespace: kubernetes-dashboard
metadata:
  name: dash-external
spec:
  type: LoadBalancer
  ports:
  - protocol: TCP
    port: 80
    targetPort: 9090
  selector:
    k8s-app: kubernetes-dashboard
  loadBalancerIP: $lbip
  loadBalancerSourceRanges:
  - $ip/32
EOM

echo "### 🪄 Creating new service 'dash-external'"
kubectl apply -f dash.yaml -n kube-system

echo "### 🔎 Get the new IP external, once it is assigned..."
kubectl get svc dash-external -n kube-system -w

gh-secret-kubeconfig.sh

#!/bin/bash

# One liner to add a new secret called CLUSTER_KUBECONFIG with access to the given AKS cluster

gh secret set CLUSTER_KUBECONFIG --body "$(az aks get-credentials -g resGrp -n clusterName --file -)"

helm-cleanup.sh

helm ls --short | xargs -L1 helm delete

kube-run.sh

#!/bin/bash

image=${1:-"alpine/curl"}
cmd=${2:-"ps -ef"}

echo "🚀 Running command:"
echo "   kubectl run cmdrunner -it --rm --image=$image --restart=Never -- $cmd"
echo

kubectl run cmdrunner -it --rm --image="$image" --privileged --restart=Never -- $cmd

pi-cluster-2024.md

Kubernetes Raspberry Pi Cluster 2024

This guide was written for Debian 12 aka Bookworm

Pre-prep:

• Download 64 bit Lite OS https://downloads.raspberrypi.com/raspios_lite_arm64/images/
• Image all SD cards with imager https://www.raspberrypi.com/software/
  • Customise the OS; enable SSH, enable WiFi, set hostnames, etc etc
• Get all nodes booted and on the network

https://computingforgeeks.com/install-kubernetes-cluster-on-debian-12-bookworm/

OS Preparation (all nodes)

Switch to root for all of this sudo su - it saves prefixing every command with sudo

Update the system and install common packages

apt update && apt -y full-upgrade
apt -y install iptables apt-transport-https gnupg2 software-properties-common apt-transport-https ca-certificates curl

Disable swap

swapoff -a
sudo dphys-swapfile swapoff && \
sudo dphys-swapfile uninstall && \
sudo systemctl disable dphys-swapfile

Enable iptables

update-alternatives --set iptables /usr/sbin/iptables-legacy
update-alternatives --set ip6tables /usr/sbin/ip6tables-legacy

Enable some kernel modules

tee /etc/modules-load.d/k8s.conf <<EOF
overlay
br_netfilter
EOF

modprobe overlay
modprobe br_netfilter

Configure IP stack

tee /etc/sysctl.d/kubernetes.conf <<EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF

sysctl --system

Install Container Runtime (all nodes)

We will use containerd. Run these commands as root user

curl -fsSL https://download.docker.com/linux/debian/gpg | gpg --dearmor -o /etc/apt/trusted.gpg.d/debian.gpg
add-apt-repository "deb [arch=$(dpkg --print-architecture)] https://download.docker.com/linux/debian $(lsb_release -cs) stable"
apt update
apt install -y containerd.io

mkdir -p /etc/containerd
containerd config default | tee /etc/containerd/config.toml
systemctl restart containerd
systemctl enable containerd

---

Appendix 1 - Static IP on Raspberry Pi OS Bookworm

sudo nmcli c show
sudo nmcli c mod 'preconfigured' ipv4.addresses 192.168.0.152/24 ipv4.method manual
sudo nmcli c mod 'preconfigured' ipv4.gateway 192.168.0.1
sudo nmcli c mod 'preconfigured' ipv4.dns 192.168.0.1

Then reboot

Other stuff

Install micro

• mkdir -p ~/.local/bin && curl https://getmic.ro | bash && mv micro ~/.local/bin