kubernetes examples

k8s.md

Pod with volumes

cat <<EOF |  kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
  name: restore
  namespace: monitoring
spec:
  securityContext:
    fsGroup: 1000       # GID del usuario del container tf-infra
  containers:
  - name: restore
    image: ubuntu:latest
    imagePullPolicy: IfNotPresent
    command: [ "/bin/sh", "-c", "--" ]
    args: [ "while true; do sleep 30; done;" ] 
    volumeMounts:
      - name: loki
        mountPath: /data/loki
      - name: prometheus
        mountPath: /data/prometheus
  restartPolicy: Never
  volumes:
  - name: loki
    persistentVolumeClaim:
      claimName: storage-loki-stack-0
  - name: prometheus
    persistentVolumeClaim:
      claimName: prometheus-kube-prometheus-stack-prometheus-db-prometheus-kube-prometheus-stack-prometheus-0
EOF

Whitelist and Maintenance mode to not allowed IPs

apiVersion: networking.k8s.io/v1 kind: Ingress metadata: annotations: # block not whitelilsted ips returns a 403 error nginx.ingress.kubernetes.io/whitelist-source-range: 1.1.1.1/32,2.2.2.2/32 nginx.ingress.kubernetes.io/server-snippet: | error_page 403 = @errorpages; # catch the error location @errorpages { return 503 "We are on maintenance mode.
Please come back later."; }

Helm

helm repo add cert-manager https://charts.jetstack.io
helm repo update
helm search repo <repo_name>
helm pull [chart URL | repo/chartname] [...] [flags]

# evaluar el values.yaml en el template
helm template ./chart

Test autoscaler

apiVersion: v1
kind: Pod
metadata:
  name: ubuntu
  namespace: devops
  labels:
    app: ubuntu
spec:
  containers:
  - image: ubuntu:latest
    imagePullPolicy: Always
    name: ubuntu
    command: [ "/bin/sh", "-c", "--" ]
    args: [ "while true; do sleep 30; done;" ]
  affinity:
    nodeAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
        nodeSelectorTerms:
          - matchExpressions:
              - key: NodeGroup
                operator: In
                values:
                  - system
  tolerations:
    - key: dedicated
      operator: Equal
      value: system
      effect: NoSchedule

apiVersion: apps/v1 kind: Deployment metadata: name: ubuntu-geko namespace: devops labels: app: ubuntu spec: replicas: 1 selector: matchLabels: app: ubuntu template: metadata: labels: app: ubuntu spec: containers: - name: ubuntu image: ubuntu:latest imagePullPolicy: Always command: [ "/bin/sh", "-c", "--" ] args: [ "while true; do sleep 30; done;" ]

EKS Migration

#!/bin/bash

# docker run -d -p 3001:3001 --name monit_scout -v scout_pro:/app/data louislam/uptime-kuma:1

# docker start monit_scout

# De 1.30 a 1.31
# 1. aplicar upgrade desde consola
# 2. aplicar upgrade desde terraform con environment 1.31
#   1. revisar versiones de plugins
# 3. Rotar nodos 
# Cordon nodes

REMOVING_VERSION="1.30"
NODOS=$(kubectl get node | grep ${REMOVING_VERSION} | awk '{print $1}')

# Cordon
for nodo in ${NODOS}
do 
  echo "Cordon ${nodo}"
  kubectl cordon ${nodo}
  kubectl get node ${nodo}
done

for NODE in ${NODOS}
do 
  kubectl get node $NODE
  EC2_ID=$(kubectl get node ${NODE} -o json | jq -r '.metadata.annotations["csi.volume.kubernetes.io/nodeid"] | fromjson | .["ebs.csi.aws.com"]')

  read -p "Press enter to continue with next Node"
  echo "Drain $NODE"
  kubectl drain $NODE --ignore-daemonsets --delete-emptydir-data --force

  echo "Drain DONE! ..."
  echo "-------------------------"
  echo "Still running PODs"
  kubectl describe node ${NODE} | awk '/Non-terminated Pods:/ {flag=1; next} /Allocated resources:/ {flag=0} flag' 
  echo  
  echo

  read -p "Remove from K8S node: ${NODE}? " yn
  if [[ $y/n =~ ^[Yy]$ ]]; then
    echo "delete node $NODE"
    kubectl delete node $NODE

    read -p "Remove Node: ${NODE} EC2_id: ${EC2_ID}? " yn
    if [[ $y/n =~ ^[Yy]$ ]]; then
      # remove EC2 and auto adjust the ASG, so no new node is deployed
      echo "autoscaling terminate-instance-in-auto-scaling-group"
      # aws autoscaling terminate-instance-in-auto-scaling-group --instance-id ${EC2_ID} --should-decrement-desired-capacity
      aws autoscaling terminate-instance-in-auto-scaling-group --instance-id ${EC2_ID} --no-should-decrement-desired-capacity
    fi
  fi
done



# NODE=""
# EC2_ID=$(kubectl get node ${NODE} -o json | jq -r '.metadata.annotations["csi.volume.kubernetes.io/nodeid"] | fromjson | .["ebs.csi.aws.com"]')
# kubectl drain $NODE --ignore-daemonsets --delete-emptydir-data --force
# kubectl describe node ${NODE} | awk '/Non-terminated Pods:/ {flag=1; next} /Allocated resources:/ {flag=0} flag' 
# kubectl delete node $NODE
# aws autoscaling terminate-instance-in-auto-scaling-group --instance-id ${EC2_ID} --no-should-decrement-desired-capacity

Infinite Pod

k apply -f - <<EOF
apiVersion: apps/v1
kind: Deployment
metadata:
  name: ubuntu-infinite
spec:
  replicas: 1
  selector:
    matchLabels:
      app: ubuntu-infinite
  template:
    metadata:
      labels:
        app: ubuntu-infinite
    spec:
      containers:
        - name: ubuntu
          image: ubuntu:latest
          command:
            - /bin/bash
            - -c
            - |
              while true; do
                sleep 3600
              done
EOF