148422597X Kubernetes Management Design Patterns [Vohra 2017-01-29] {E559F6BB}

Chapter 9 ■ Scheduling Pods on Nodes
Figure 9-59. Setting all the kubernetes.io/image-name key values to non existing values
Delete the pod with-labels and create the pod again. The pod is still scheduled even though none of
the nodes have matching labels, as shown in Figure 9-60. By comparison, when we used the node affinity
requiredDuringSchedulingIgnoredDuringExecution with none of the nodes having matching labels, the
pods were placed in Pending status until a matching label was added. Now the pod is scheduled because the
preferredDuringSchedulingIgnoredDuringExecution setting is not binding and is only a hint.
Figure 9-60. Pods are scheduled even though no nodes with matching labels are found
The nodeSelector field if specified with node affinity preferredDuringSchedulingIgnoredDuringExecution
is still guaranteed. Add the nodeSelector field with the label kubernetes.io/image-name: nginx as shown in
Figure 9-61. All the other matching expressions are set to kubernetes.io/image-name: hello-world.
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