[SPARK-53933] Add Apache Iceberg example

### What changes were proposed in this pull request?

This PR aims to add `Apache Iceberg` example.

### Why are the changes needed?

To provide an working example of `Apache Spark 4.0.1` and `Apache Iceberg 1.10.0`.

1. Prepare the storage

```
$ kubectl apply -f examples/localstack.ym
```

2. Launch `Spark Connect Server` with `Apache Iceberg` setting.

```
$ kubectl apply -f examples/spark-connect-server-iceberg.yaml
```

3. Setup port-forwarding to test

```
$ kubectl port-forward spark-connect-server-iceberg-0-driver 15002
```

4. Test with `Apache Iceberg Spark Quickstart` guideline.
- https://iceberg.apache.org/spark-quickstart/

```scala
$ bin/spark-connect-shell --remote sc://localhost:15002

scala> sql("""CREATE TABLE taxis(vendor_id bigint, trip_id bigint, trip_distance float, fare_amount double, store_and_fwd_flag string) PARTITIONED BY (vendor_id);""").show()

scala> sql("""INSERT INTO taxis VALUES (1, 1000371, 1.8, 15.32, 'N'), (2, 1000372, 2.5, 22.15, 'N'), (2, 1000373, 0.9, 9.01, 'N'), (1, 1000374, 8.4, 42.13, 'Y');""").show()

scala> sql("SELECT * FROM taxis").show(false)
+---------+-------+-------------+-----------+------------------+
|vendor_id|trip_id|trip_distance|fare_amount|store_and_fwd_flag|
+---------+-------+-------------+-----------+------------------+
|1        |1000374|8.4          |42.13      |Y                 |
|1        |1000371|1.8          |15.32      |N                 |
|2        |1000372|2.5          |22.15      |N                 |
|2        |1000373|0.9          |9.01       |N                 |
+---------+-------+-------------+-----------+------------------+

scala> sql("SELECT * FROM taxis.history").show(false)
+-----------------------+-------------------+---------+-------------------+
|made_current_at        |snapshot_id        |parent_id|is_current_ancestor|
+-----------------------+-------------------+---------+-------------------+
|2025-10-16 03:53:04.063|6463217948421571140|NULL     |true               |
+-----------------------+-------------------+---------+-------------------+

scala> sql("SELECT * FROM taxis VERSION AS OF 6463217948421571140").show(false)
+---------+-------+-------------+-----------+------------------+
|vendor_id|trip_id|trip_distance|fare_amount|store_and_fwd_flag|
+---------+-------+-------------+-----------+------------------+
|1        |1000374|8.4          |42.13      |Y                 |
|1        |1000371|1.8          |15.32      |N                 |
|2        |1000372|2.5          |22.15      |N                 |
|2        |1000373|0.9          |9.01       |N                 |
+---------+-------+-------------+-----------+------------------+
```

5. Check the data in the storage.

```
rootlocalstack:/opt/code/localstack# awslocal s3 ls s3://warehouse/ --recursive
2025-10-16 03:53:03       1545 taxis/data/vendor_id=1/00000-3-749fe2e5-bbe3-4f0e-b976-a21749550705-0-00002.parquet
2025-10-16 03:53:03       1590 taxis/data/vendor_id=2/00000-3-749fe2e5-bbe3-4f0e-b976-a21749550705-0-00001.parquet
2025-10-16 03:53:04       7559 taxis/metadata/9f629d40-ce91-4822-aeee-283d53ec5ef6-m0.avro
2025-10-16 03:53:04       4446 taxis/metadata/snap-6463217948421571140-1-9f629d40-ce91-4822-aeee-283d53ec5ef6.avro
2025-10-16 03:52:47       1006 taxis/metadata/v1.metadata.json
2025-10-16 03:53:04       1970 taxis/metadata/v2.metadata.json
2025-10-16 03:53:04          1 taxis/metadata/version-hint.text
```

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

Manually tested.

### Was this patch authored or co-authored using generative AI tooling?

No.

Closes #394 from dongjoon-hyun/SPARK-53933.

Authored-by: Dongjoon Hyun <[email protected]>
Signed-off-by: Dongjoon Hyun <[email protected]>

Author: dongjoon-hyun

examples/localstack.yml

@@ -41,6 +41,7 @@ spec:
             awslocal s3 mb s3://spark-events;
             awslocal s3 mb s3://ingest;
             awslocal s3 mb s3://data;
+            awslocal s3 mb s3://warehouse;
             awslocal s3 cp /opt/code/localstack/Makefile s3://data/
 ---
 apiVersion: v1

examples/spark-connect-server-iceberg.yaml

@@ -0,0 +1,45 @@
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+apiVersion: spark.apache.org/v1
+kind: SparkApplication
+metadata:
+  name: spark-connect-server-iceberg
+spec:
+  mainClass: "org.apache.spark.sql.connect.service.SparkConnectServer"
+  sparkConf:
+    spark.dynamicAllocation.enabled: "true"
+    spark.dynamicAllocation.maxExecutors: "3"
+    spark.dynamicAllocation.minExecutors: "3"
+    spark.dynamicAllocation.shuffleTracking.enabled: "true"
+    spark.hadoop.fs.s3a.access.key: "test"
+    spark.hadoop.fs.s3a.endpoint: "http://localstack:4566"
+    spark.hadoop.fs.s3a.path.style.access: "true"
+    spark.hadoop.fs.s3a.secret.key: "test"
+    spark.jars.ivy: "/tmp/.ivy2.5.2"
+    spark.jars.packages: "org.apache.hadoop:hadoop-aws:3.4.1,org.apache.iceberg:iceberg-spark-runtime-4.0_2.13:1.10.0"
+    spark.kubernetes.authenticate.driver.serviceAccountName: "spark"
+    spark.kubernetes.container.image: "apache/spark:4.0.1"
+    spark.kubernetes.driver.pod.excludedFeatureSteps: "org.apache.spark.deploy.k8s.features.KerberosConfDriverFeatureStep"
+    spark.kubernetes.executor.podNamePrefix: "spark-connect-server-iceberg"
+    spark.scheduler.mode: "FAIR"
+    spark.sql.catalog.s3.type: "hadoop"
+    spark.sql.catalog.s3.warehouse: "s3a://warehouse"
+    spark.sql.catalog.s3: "org.apache.iceberg.spark.SparkCatalog"
+    spark.sql.defaultCatalog: "s3"
+    spark.sql.extensions: "org.apache.iceberg.spark.extensions.IcebergSparkSessionExtensions"
+  applicationTolerations:
+    resourceRetainPolicy: OnFailure
+  runtimeVersions:
+    sparkVersion: "4.0.1"