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