A data scientist needs to train a large PyTorch model on a custom dataset using Vertex AI. The training script expects data from Cloud Storage and uses GPU acceleration. Which option correctly configures a custom training job with a pre-built container for PyTorch and attaches a single NVIDIA V100 GPU?
The PyTorch GPU pre-built container supplies the training runtime, while worker_pool_specs declares machine_type, accelerator_type='NVIDIA_TESLA_V100' and accelerator_count=1, attaching exactly one V100. This satisfies both the custom PyTorch training and single-GPU constraints without building a custom image.
Why this answer
Vertex AI custom training jobs use worker_pool_specs to define the machine type, container image, and accelerator configuration. The correct configuration uses the pre-built PyTorch GPU container and specifies machine_type='n1-standard-4', accelerator_type='NVIDIA_TESLA_V100', and accelerator_count=1 in the worker pool spec. This is the documented Vertex AI pattern for attaching a single V100 GPU.
Exam trap
PMLE often tests the exact API field names and the distinction between Vertex AI custom training and legacy AI Platform Training — candidates pick 'custom container' or 'AI Platform Training' because they sound plausible, but only the worker_pool_specs configuration with the pre-built PyTorch GPU image and correct accelerator_type is valid on Vertex AI.
How to eliminate wrong answers
Option A is wrong because while a custom container is valid, the answer omits the required worker_pool_specs structure and the correct accelerator_type string — 'accelerator_count=1 in the machine spec' is not a valid Vertex AI API field; the field is accelerator_count inside worker_pool_specs.machine_spec. Option C is wrong because AI Platform Training (the legacy service) uses --scale-tier BASIC_GPU, which does not let you specify a V100 or a pre-built PyTorch container in the Vertex AI manner — it's a different, deprecated service. Option D is wrong because AutoML does not support custom PyTorch training scripts or GPU runtime selection; AutoML is for tabular/image/text models with managed training, not custom code.