Taints and tolerations work together to ensure that pods are not scheduled onto inappropriate nodes. One or more taints are applied to a node; this marks that the node should not accept any pods that do not tolerate the taints. Tolerations are applied to pods, and allow (but do not require) the pods to schedule onto nodes with matching taints.
Even placed a taint on Master node,you can specify a toleration for a pod in the PodSpec, the pod would be able to schedule onto Master node:
tolerations:
- key: node-role.kubernetes.io/master
effect: NoSchedule
To learn more,see Taints and Tolerations