Letting only one elasticsearch pod come up on a node in Kubernetes

As Egor suggested, you need podAntiAffinity:

apiVersion: apps/v1kind: Deploymentmetadata:  name: redis-cachespec:  selector:    matchLabels:      app: store  replicas: 3  template:    metadata:      labels:        app: store    spec:      affinity:        podAntiAffinity:          requiredDuringSchedulingIgnoredDuringExecution:          - labelSelector:              matchExpressions:              - key: app                operator: In                values:                - store            topologyKey: "kubernetes.io/hostname"

Source: https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#always-co-located-in-the-same-node

So, with your current label, it might look like this:

spec:  affinity:    nodeAffinity:    # node affinity stuff here    podAntiAffinity:      requiredDuringSchedulingIgnoredDuringExecution:      - labelSelector:          matchExpressions:          - key: "test.service.es-master"            operator: In            values:            - "true"        topologyKey: "kubernetes.io/hostname"

Ensure that you put this in the correct place in your yaml, or else it won't work.

Firstly, both in your initial manifest and even in the updated manifest you are using topologyKey for nodeAffinity which will give you an error while trying to deploy those manifest using kubectl create or kubectl apply because there is no api key called topologyKey for nodeAffinity Ref doc

Secondly, you are using a key called test.service.es-master for your nodeAffinity are you sure your "node" has those labels? please confirm by this command kubectl get nodes --show-labels

Lastly, Augmenting to @Laszlo answer and your @bitswazsky comment on it to simplify it, you can use the below code:

Here I have used a node label (as key) called role to identify the node, you can add that to your existing clusters' node by executing this command kubectl label nodes <node-name> role=platform

selector:    matchLabels:      component: nginx  template:    metadata:      labels:        component: nginx    spec:      affinity:        nodeAffinity:          requiredDuringSchedulingIgnoredDuringExecution:            nodeSelectorTerms:            - matchExpressions:              - key: role                operator: In                values:                - platform        podAntiAffinity:          requiredDuringSchedulingIgnoredDuringExecution:          - labelSelector:              matchExpressions:              - key: component                operator: In                values:                - nginx            topologyKey: kubernetes.io/hostname

This works for me with Kubernetes 1.11.5:

apiVersion: extensions/v1beta1kind: Deploymentmetadata:  name: nginxspec:  replicas: 3  selector:    matchLabels:      test.service.es-master: "true"  template:    metadata:      labels:        test.service.es-master: "true"    spec:      affinity:        podAntiAffinity:          requiredDuringSchedulingIgnoredDuringExecution:          - labelSelector:              matchExpressions:              - key: test.service.es-master                operator: In                values:                - "true"            topologyKey: kubernetes.io/hostname        nodeAffinity:          requiredDuringSchedulingIgnoredDuringExecution:            nodeSelectorTerms:            - matchExpressions:              - key: test.service.es-master                operator: In                values:                  - "true"      containers:      - image: nginx:1.7.10        name: nginx

I don't know why you chose the same key/value for the pod deployment selector label, as for the node selector. They are confusing as a minimum...