document content pod anti-affinity recommendations

[dbkegley]

Connect pod anti-affinity (Connect server pods should avoid other server pods) - useful when there are multiple Connect replicas in the deployment

affinity:
  # avoid other connect server pods
  podAntiAffinity:
    preferredDuringSchedulingIgnoredDuringExecution:
      - weight: 100
        podAffinityTerm:
          labelSelector:
            matchExpressions:
              - key: app.kubernetes.io/name
                operator: In
                values:
                  - rstudio-connect
          topologyKey: kubernetes.io/hostname

Content pods should avoid other content pods - useful on busy clusters to ensure that content pods are less likely to be evicted due to node memory-pressure

# Content pod anti-affinity settings.
# These settings will tell the content pods to avoid other content pods which should help the content pods be more evenly
# distributed among the available EKS cluster nodes.
launcher:
  enabled: true
  templateValues:
    pod:
      affinity:
        podAntiAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
            # avoid EKS cluster nodes with running content jobs during scheduling
            - weight: 100
              podAffinityTerm:
                labelSelector:
                  # spread content pods using a label that is added by Connect
                  matchExpressions:
                    - key: connect.rstudio.com/content-guid
                      operator: Exists
                topologyKey: kubernetes.io/hostname