aidp-aws-s3 — AWS S3 via the S3A connector

Read or write s3a://<bucket>/<key> paths from AIDP Spark using AWS access keys. Optional boto3 path for management operations (list, copy, head).

When to use

• AIDP needs to consume or land data in AWS S3.
• Mentioned: "S3", "s3a", "AWS bucket".

When NOT to use

• For OCI Object Storage → aidp-object-storage.
• For Azure ADLS Gen2 → aidp-azure-adls.

Cluster prerequisite — runtime-load BOTH hadoop-aws and aws-java-sdk-bundle

The AIDP tpcds cluster does NOT have org.apache.hadoop.fs.s3a.S3AFileSystem pre-installed (verified live 2026-04-27). Both hadoop-aws-<ver>.jar (~1 MB) AND aws-java-sdk-bundle-<ver>.jar (~280 MB) must be runtime-loaded. Match hadoop-aws to the cluster's exact Hadoop version (spark._jvm.org.apache.hadoop.util.VersionInfo.getVersion() — typically 3.3.4 for Spark 3.5.0). Mismatch produces NoSuchMethodError deep in org.apache.hadoop.fs.s3a.

Beyond the standard runtime-load + DriverManager pattern, S3A also requires telling Hadoop's Configuration which classloader to use — Hadoop's FileSystem.get() uses Configuration.getClassLoader(), not the JVM thread context loader.

Spark read (S3A, runtime-loaded driver)

import os, urllib.request
from py4j.java_gateway import java_import

# 1. Confirm cluster's Hadoop version + match hadoop-aws jar
HADOOP_VER = spark._jvm.org.apache.hadoop.util.VersionInfo.getVersion()
print("hadoop:", HADOOP_VER)  # e.g. 3.3.4

JARS = {
    f"/tmp/hadoop-aws-{HADOOP_VER}.jar":
        f"https://repo1.maven.org/maven2/org/apache/hadoop/hadoop-aws/{HADOOP_VER}/hadoop-aws-{HADOOP_VER}.jar",
    "/tmp/aws-java-sdk-bundle-1.12.262.jar":
        "https://repo1.maven.org/maven2/com/amazonaws/aws-java-sdk-bundle/1.12.262/aws-java-sdk-bundle-1.12.262.jar",
}
for path, url in JARS.items():
    if not os.path.exists(path):
        urllib.request.urlretrieve(url, path)

# 2. Build URLClassLoader covering BOTH jars + set on Hadoop Configuration
gw = spark._sc._gateway
URLArr = gw.new_array(spark._jvm.java.net.URL, len(JARS))
for i, p in enumerate(JARS):
    URLArr[i] = spark._jvm.java.io.File(p).toURI().toURL()
sysCL = spark._jvm.java.lang.ClassLoader.getSystemClassLoader()
ucl = spark._jvm.java.net.URLClassLoader(URLArr, sysCL)

hconf = spark._jsc.hadoopConfiguration()
hconf.setClassLoader(ucl)  # CRITICAL — Hadoop FileSystem lookup uses this, not the thread context

# 3. Configure S3A credentials + endpoint
hconf.set("fs.s3a.access.key", os.environ["S3_ACCESS_KEY"])
hconf.set("fs.s3a.secret.key", os.environ["S3_SECRET_KEY"])
hconf.set("fs.s3a.endpoint", "s3.amazonaws.com")  # or s3.<region>.amazonaws.com
hconf.set("fs.s3a.aws.credentials.provider",
          "org.apache.hadoop.fs.s3a.SimpleAWSCredentialsProvider")
hconf.set("fs.s3a.impl", "org.apache.hadoop.fs.s3a.S3AFileSystem")

# 4. Distribute the jars to executors (driver-only registration won't work for cluster reads)
for p in JARS:
    spark._jsc.addJar(p)

# 5. Read — works for csv/json/parquet/delta
df = spark.read.option("header", "true").csv(
    f"s3a://{os.environ['S3_BUCKET']}/{os.environ['S3_FILE']}"
)
df.show()

Live-validated 2026-04-27: 2 rows from s3a://test-data-sep3-2025/csv/sample.csv via this pattern.

boto3 fallback (management ops, not data plane)

import boto3, os

s3 = boto3.client(
    "s3",
    aws_access_key_id     = os.environ["S3_ACCESS_KEY"],
    aws_secret_access_key = os.environ["S3_SECRET_KEY"],
    region_name           = os.environ.get("S3_REGION", "us-east-1"),
)

resp = s3.list_objects_v2(Bucket=os.environ["S3_BUCKET"], Prefix="")
for obj in resp.get("Contents", []):
    print(obj["Key"])

Gotchas

• Use s3a:// (the Hadoop driver), not s3:// or s3n://. The latter two are deprecated and may not be present in the cluster.
• aws-java-sdk-bundle version drift — pin to the version hadoop-aws was built against. Lab clusters often need this jar installed; the symptom of mismatch is NoSuchMethodError deep in org.apache.hadoop.fs.s3a when listing/reading.
• Configuration.setClassLoader is required after runtime-load — Hadoop's FileSystem.get() calls Configuration.getClassByName() which uses the Configuration's classloader (not the JVM thread context). Without hconf.setClassLoader(ucl), you get ClassNotFoundException: Class org.apache.hadoop.fs.s3a.S3AFileSystem not found even though you just registered the jar.
• Secrets in env vars only. Never hard-code keys in notebooks. Source from .env/OCI Vault.
• Region — boto3.client('s3', region_name=...) is required for non-default regions; for the Spark path the bucket region is auto-discovered, but you may need fs.s3a.endpoint=s3.<region>.amazonaws.com for non-us-east-1 if listings fail.
• boto3 is NOT pre-installed on AIDP cluster and PyPI mirror is typically unreachable. For management ops (list, copy, head), drive from local rather than cluster.
• Egress cost & latency — S3 reads from AIDP cross-cloud. For heavy ETL, copy to OCI Object Storage once and read locally.

References

• Official sample: oracle-samples/oracle-aidp-samples → data-engineering/ingestion/Ingest_from_Multi_Cloud.ipynb
• Hadoop AWS docs: https://hadoop.apache.org/docs/stable/hadoop-aws/tools/hadoop-aws/