Kubernetes pod affinity and anti affinity

https://kubernetes.io/docs/concepts/scheduling-eviction/assign-pod-node/#affinity-and-anti-affinity

• Elasticsearch PodAntiAffinity official example

0/11 nodes are available: 1 Insufficient cpu, 1 Too many pods, 10 nodes(s) didn't match Pod's node affinity/selector
0/2 nodes are available: 1 Too many pods, 1 nodes(s) didn't match Pod's node affinity/selector

Official examples

apiVersion: v1

kind: Pod

metadata:

  name: with-node-affinity

spec:

  affinity:

    nodeAffinity:

      requiredDuringSchedulingIgnoredDuringExecution:

        nodeSelectorTerms:

        - matchExpressions:

          - key: topology.kubernetes.io/zone

            operator: In

            values:

            - antarctica-east1

            - antarctica-west1

      preferredDuringSchedulingIgnoredDuringExecution:

      - weight: 1

        preference:

          matchExpressions:

          - key: another-node-label-key

            operator: In

            values:

            - another-node-label-value

  containers:

  - name: with-node-affinity

    image: registry.k8s.io/pause:2.0

apiVersion: v1

kind: Pod

metadata:

  name: with-pod-affinity

spec:

  affinity:

    podAffinity:

      requiredDuringSchedulingIgnoredDuringExecution:

      - labelSelector:

          matchExpressions:

          - key: security

            operator: In

            values:

            - S1

        topologyKey: topology.kubernetes.io/zone

    podAntiAffinity:

      preferredDuringSchedulingIgnoredDuringExecution:

      - weight: 100

        podAffinityTerm:

          labelSelector:

            matchExpressions:

            - key: security

              operator: In

              values:

              - S2

          topologyKey: topology.kubernetes.io/zone

  containers:

  - name: with-pod-affinity

    image: registry.k8s.io/pause:2.0

Related

• Kubernetes Pod Topology Spread Constraints

default-scheduler

See also

• Pods: kubectl apply, kubectl [ pod get | top | delete | describe pods ], InitContainers, PodInitializing, CrashLoopBackOff, ImagePullPolicy:, NodeAffinity, NodeSelector, Terminated