Kubernetes notes

• Spread pods across nodes with topologySpreadConstraints

      topologySpreadConstraints:
        - maxSkew: 1
          topologyKey: kubernetes.io/hostname
          whenUnsatisfiable: DoNotSchedule
          labelSelector:
            matchLabels:
              app: demo

• Spread pods across nodes with topologySpreadConstraints

      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            - labelSelector:
                matchExpressions:
                  - key: app
                    operator: In
                    values:
                      - demo
              topologyKey: kubernetes.io/hostname

• Show pod with id

kubectl get pods -A -o custom-columns=PodName:.metadata.name,PodUID:.metadata.uid

• Delete resources

kubectl get pods,svc,deploy,sts -o name | xargs -n1 -I{} kubectl patch {} --type=merge -p '{"metadata":{"finalizers":[]}}'

• Delete all resource

kga | grep -v NAME | awk '{ print $1 }' | xargs kubectl delete --force

• Change storage class default

kubectl patch sc openebs-device -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"false"}}}'

kubectl patch sc openebs-hostpath -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'