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Data Preparation for Machine LearninghardMultiple ChoiceObjective-mapped

MLA-C01 Data Preparation for Machine Learning Practice Question

Exhibit

import sys
from awsglue.transforms import *
from awsglue.utils import getResolvedOptions
from pyspark.context import SparkContext
from awsglue.context import GlueContext
from awsglue.job import Job

args = getResolvedOptions(sys.argv, ['JOB_NAME'])
sc = SparkContext()
glueContext = GlueContext(sc)
spark = glueContext.spark_session
job = Job(glueContext)
job.init(args['JOB_NAME'], args)

raw = glueContext.create_dynamic_frame.from_options(
    connection_type="s3",
    connection_options={"paths": ["s3://bucket/input/year=2023/month=01/"]},
    format="json")

transformed = raw.select_fields(["col1", "col2"]).rename_field("col1", "new_col")

glueContext.write_dynamic_frame.from_options(
    frame=transformed,
    connection_type="s3",
    connection_options={"path": "s3://bucket/output/transformed"},
    format="parquet")

job.commit()

Refer to the exhibit. A data engineer runs an AWS Glue ETL job with the following script portion. The job fails with an error: 'An error occurred while calling o113.pyWriteDynamicFrame. No such file or directory'. What is the most likely cause?

⚠ Common exam trap

The trap here is that candidates often focus on data format or schema issues, overlooking the subtle file system requirement for a trailing slash in the output path, which is a common source of runtime errors in Spark-based ETL jobs.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

The output S3 path is missing a trailing slash

The error 'No such file or directory' when calling `pyWriteDynamicFrame` typically occurs because AWS Glue expects the output S3 path to end with a trailing slash to denote a directory. Without it, Glue may interpret the path as a file name rather than a directory, leading to a failure when attempting to write the Parquet files. Adding a trailing slash (e.g., `s3://bucket/output/`) resolves the issue.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • The output format 'parquet' is not supported by Glue

    Why it's wrong here

    Parquet is supported.

  • The input partition path is incorrect because it includes the partition key

    Why it's wrong here

    Including partition key in path is acceptable.

  • The output S3 path is missing a trailing slash

    Why this is correct

    Glue DynamicFrame write expects a directory path ending with '/'.

  • The schema contains a column with a reserved name

    Why it's wrong here

    Error message does not indicate schema issue.

Visual reference

Client Recursive Resolver Root DNS (13 root servers) TLD DNS (.com, .org, …) Authoritative example.com query IP addr answer

Quick reference

AWS S3 Storage Class Comparison

Storage ClassMin DurationRetrievalUse Case
S3 StandardNoneImmediateFrequently accessed data
S3 Standard-IA30 daysImmediateInfrequent access, rapid retrieval
S3 One Zone-IA30 daysImmediateNon-critical infrequent data
S3 Intelligent-TieringNoneImmediate–hoursUnknown or changing access patterns
S3 Glacier Instant90 daysMillisecondsArchive with instant retrieval
S3 Glacier Flexible90 daysMinutes–hoursArchive, flexible retrieval
S3 Glacier Deep Archive180 daysHoursLong-term compliance archive

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Written by Johnson Ajibi, MSc IT Security

Senior Network & Security Engineer · founder of Courseiva

This MLA-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the MLA-C01 exam.