Sharing ephemeral cache between containers in a Pod

WHAT IT TESTS: Whether you match volume lifecycle to data lifecycle. ANSWER OUTLINE: Use an emptyDir volume. Declare it once under the Pod's volumes, then add a volumeMount referencing it in each container at the desired path. emptyDir is created empty when the Pod is assigned to a node and is deleted permanently when the Pod is removed, so it perfectly fits shared, throwaway cache. You can set medium: Memory to back it with tmpfs. RED FLAG: Proposing a PersistentVolume or hostPath, which outlive the Pod or tie data to a node.