How to create statefulset with nodeAffinity

Question

I'm trying to create a statefulset in kubernetes 1.9 with nodeAffinity. I found some examples with a simple nodeselector, but that is not really what I would like to accomplish. I want to make sure that statefulset instances always start on the same node, like this:

statefulpod-0 on node-0
statefulpod-1 on node-1
statefulpod-2 on node-2

I tried labelling the corresponding nodes with the statefulpod-name, and using downward api in nodeselector or nodeaffinity, but I cannot produce a working yaml to do this.

The example:

affinity:
  nodeAffinity:
    requiredDuringSchedulingIgnoredDuringExecution:
    - nodeSelectorTerms:
        matchExpressions:
        - key: statefulpodname
          operator: In
          values:
          - valueFrom:
              fieldRef:
                fieldPath: metadata.name

The error:

ValidationError(StatefulSet.spec.template.spec.affinity.nodeAffinity.requiredDuringSchedulingIgnoredDuringExecution): invalid type for io.k8s.api.core.v1.NodeSelector: got "map", expected "array";

The example:

nodeSelector:
  statefulpodname:
  - valueFrom:
        fieldRef:
          fieldPath: metadata.name

The error:

invalid type for io.k8s.api.core.v1.PodSpec.nodeSelector: got "array", expected "string"

Any ideas?

Seems like your validation errors don't really match your provided yaml snippets. Are you sure you provided up-to-date ones? — Nebril, Jan 12 '18 at 10:30
The above snippets are off course only a small part of the actual statefulset yaml, but the validation errors match the provided snippets afaik — Rosse, Jan 12 '18 at 10:41

score 0 · Answer 1 · answered Jan 12 '18 at 11:11

0

as error states got "map", expected "array";, try with :

- nodeSelectorTerms:
  - matchExpressions:
...

answered Jan 12 '18 at 11:11

Radek 'Goblin' Pieczonka

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I tried but this results in the same error. I guess downward API can only be used in env and volumes? – Rosse Jan 12 '18 at 12:16

score 0 · Answer 2 · answered Aug 19 '21 at 08:53

For future reference, the YAML needs to be as follows;

spec: 
 affinity:
   nodeAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
        nodeSelectorTerms:
          - matchExpressions:
            - key: <key>
              operator: <operator>
              values:
              - <values>

Notice the placement of dash (-) characters.

How to create statefulset with nodeAffinity

2 Answers2