masterType

Optional. Specifies the type of virtual machine to use for your training job's master worker. You must specify this field when scaleTier is set to CUSTOM. You can use certain Compute Engine machine types directly in this field. See the /ai-platform/training/docs/machine-types#compute-engine-machine-types. Alternatively, you can use the certain legacy machine types in this field. See the /ai-platform/training/docs/machine-types#legacy-machine-types. Finally, if you want to use a TPU for training, specify cloud_tpu in this field. Learn more about the /ai-platform/training/docs/using-tpus#configuring_a_custom_tpu_machine.