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Apache Iceberg
Apache Iceberg is quickly becoming the industry standard for interfacing with data on data lakes. A lot of the time when people first try out Iceberg they do so using Apache Spark.
Often to start spark up you may run a command like this:
spark-sql --packages org.apache.iceberg:iceberg-spark-runtime-3.4_2.12:1.3.1 \
--conf spark.sql.catalog.icebergcatalog=org.apache.iceberg.spark.SparkCatalog \
--conf spark.sql.catalog.icebergcatalog.type=hadoop \
--conf spark.sql.catalog.icebergcatalog.warehouse=$PWD/warehouse
You can test out the command above in a docker container with this command:
docker run -it --name spark34 alexmerced/spark34
Then run the following sql statement
CREATE TABLE icebergcatalog.names (name STRING) USING iceberg;
The goal of this article is help demystify this so you can configure Spark for Iceberg in any context.
Spark Configurations
Spark configs can be defined in a few ways:
- As flags when starting Spark
- Using Imperitive function calls
Flags
There are are several flags you can pass to the spark-shell
or spark-sql
commands.
-
--package
will identify maven packages you want installed and useable during the Spark session
--packages org.projectnessie:nessie-spark-3.2-extensions:0.43.0,org.apache.iceberg:iceberg-spark-runtime-3.2_2.12:0.14.0,software.amazon.awssdk:bundle:2.17.178,software.amazon.awssdk:url-connection-client:2.17.178
-
--jar
will allow you to pass paths to existing
--jars /home/docker/iceberg-spark-runtime-3.2_2.12-1.0.0.jar,/home/docker/nessie-spark-extensions-3.2_2.12-0.44.0.jar
-
--conf
will allow you configure many properties of your spark session in a "key"="value" format.
--conf spark.sql.extensions=org.apache.iceberg.spark.extensions.IcebergSparkSessionExtensions \
--conf spark.sql.catalog.spark_catalog=org.apache.iceberg.spark.SparkSessionCatalog \
Function Calls
Similarly, you can configure your Spark Session directly from your Scala or Python Spark scripts:
SCALA
val conf: SparkConf = new SparkConf()
conf.setAppName("yo")
conf.set("spark.jars.packages", "org.projectnessie:nessie-spark-3.2-extensions:0.43.0,org.apache.iceberg:iceberg-spark-runtime-3.2_2.12:0.14.0,software.amazon.awssdk:bundle:2.17.178,software.amazon.awssdk:url-connection-client:2.17.178")
conf.set(spark.sql.catalog.spark_catalog","org.apache.iceberg.spark.SparkSessionCatalog")
PYTHON
conf = SparkConf()
conf.set(
"spark.jars.packages",
"org.projectnessie:nessie-spark-3.2-extensions:0.43.0,org.apache.iceberg:iceberg-spark-runtime-3.2_2.12:0.14.0,software.amazon.awssdk:bundle:2.17.178,software.amazon.awssdk:url-connection-client:2.17.178",
)
conf.set("spark.sql.catalog.spark_catalog", "org.apache.iceberg.spark.SparkSessionCatalog")
Packages
Here is a list of the some of the packages you may want to include with your --packages
flag and why.
Library | Purpose |
---|---|
org.apache.iceberg:iceberg-spark-runtime-3.3_2.12:1.0.0 | The main iceberg library, make sure to use the right one for the version of spark and iceberg you are using |
org.projectnessie:nessie-spark-extensions-3.3_2.12:0.44.0 | Library for working with Nessie based catalogs like Dremio Arctic |
software.amazon.awssdk:bundle:2.17.178,software.amazon.awssdk:url-connection-client:2.17.178 | Libraries for working with AWS S3 |
Configurations
Configuration | Purpose | Possible Values |
---|---|---|
spark.sql.extensions | Configure any extensions of SQL support in Spark. Each extension can be seperated with a comma | "org.apache.iceberg.spark.extensions.IcebergSparkSessionExtensions,org.projectnessie.spark.extensions.NessieSparkSessionExtensions" |
spark.sql.catalog.CatalogName | This configures a new catalog under whatever name you want (just change CatalogName to desired name) to a particular implementation of SparkCatalog | org.apache.iceberg.spark.SparkCatalog |
spark.sql.catalog.CatalogName.io-impl | This changes IO implementations of the target catalog, mainly changed for writing to Object Storage | org.apache.iceberg.aws.s3.S3FileIO |
spark.sql.catalog.CatalogName.warehouse | Determines where new tables will be written to for that particular catalog | A file or S3 path |
spark.sql.catalog.CatalogName.catalog-impl | The particular type of catalog your using | Nessie - org.apache.iceberg.nessie.NessieCatalog , Hive - NA, JDBC - org.apache.iceberg.jdbc.JdbcCatalog , AWS Glue - org.apache.iceberg.aws.glue.GlueCatalog
|
Amazon S3 Credentials
--conf spark.hadoop.fs.s3a.access.key=$AWS_ACCESS_KEY \
--conf spark.hadoop.fs.s3a.secret.key=$AWS_SECRET_ACCESS_KEY
Environmental Variables
In a lot of the upcoming snippets I'll be using different environmental variables. If you want to use the snippets as is, then define the follow environmental variables:
export TOKEN=XXXXXX
export WAREHOUSE=s3a://.../
export AWS_ACCESS_KEY_ID=XXXXXX
export AWS_SECRET_ACCESS_KEY=XXXXXX
export URI=https://...
export AWS_REGION=us-east-1
export DB_USERNAME=xxxxxx
export DB_PASSWORD=xxxxx
- TOKEN: auth token for Nessie catalogs
- WAREHOUSE: Where tables will be written
- AWS_XXXX= AWS Credentials
- URI= The Hive, Nessie or JDBC URI
- DB_USERNAME and DB_PASSWORD are for using a JDBC database like mySQL or Postgres
Sample Configurations
Below you'll find sample configurations for many catalog types for reference.
If you want to try some of these in a locally running Docker container with Spark, use this command to spin one up.
docker run -it -p 8080:8080 --name spark-playground alexmerced/spark33playground
NOTE: port 8080 is exposed in case you want run a Jupyter Notebook server in the container
HIVE
spark-sql --packages org.apache.iceberg:iceberg-spark-runtime-3.3_2.12:1.0.0\
--conf spark.sql.extensions=org.apache.iceberg.spark.extensions.IcebergSparkSessionExtensions \
--conf spark.sql.catalog.spark_catalog=org.apache.iceberg.spark.SparkSessionCatalog \
--conf spark.sql.catalog.spark_catalog.type=hive \
--conf spark.sql.catalog.hive=org.apache.iceberg.spark.SparkCatalog \
--conf spark.sql.catalog.hive.type=hadoop \
--conf spark.sql.catalog.hive.uri=$URI \
--conf spark.sql.catalog.hive.warehouse=$WAREHOUSE
AWS GLUE
spark-sql --packages "org.apache.iceberg:iceberg-spark-runtime-3.3_2.12:1.0.0,software.amazon.awssdk:bundle:2.17.178,software.amazon.awssdk:url-connection-client:2.17.178" \
--conf spark.sql.catalog.glue=org.apache.iceberg.spark.SparkCatalog \
--conf spark.sql.catalog.glue.warehouse=$WAREHOUSE \
--conf spark.sql.catalog.glue.catalog-impl=org.apache.iceberg.aws.glue.GlueCatalog \
--conf spark.sql.catalog.glue.io-impl=org.apache.iceberg.aws.s3.S3FileIO \
--conf spark.hadoop.fs.s3a.access.key=$AWS_ACCESS_KEY \
--conf spark.hadoop.fs.s3a.secret.key=$AWS_SECRET_ACCESS_KEY
NESSIE/DREMIO ARCTIC
Nessie catalogs provide you git-like semantics with your Iceberg catalogs (Merging, Branching, Rollbacks) and if you want to get hands on to see how this works try this Dremio Arctic tutorial.
spark-sql --packages "org.apache.iceberg:iceberg-spark-runtime-3.3_2.12:1.0.0,org.projectnessie:nessie-spark-extensions-3.3_2.12:0.44.0,software.amazon.awssdk:bundle:2.17.178,software.amazon.awssdk:url-connection-client:2.17.178" \
--conf spark.sql.extensions="org.apache.iceberg.spark.extensions.IcebergSparkSessionExtensions,org.projectnessie.spark.extensions.NessieSparkSessionExtensions" \
--conf spark.sql.catalog.nessie.uri=$ARCTIC_URI \
--conf spark.sql.catalog.nessie.ref=main \
--conf spark.sql.catalog.nessie.authentication.type=BEARER \
--conf spark.sql.catalog.nessie.authentication.token=$TOKEN \
--conf spark.sql.catalog.nessie.catalog-impl=org.apache.iceberg.nessie.NessieCatalog \
--conf spark.sql.catalog.nessie.warehouse=$WAREHOUSE \
--conf spark.sql.catalog.nessie=org.apache.iceberg.spark.SparkCatalog \
--conf spark.sql.catalog.nessie.io-impl=org.apache.iceberg.aws.s3.S3FileIO
JDBC
This allows you to use Postgres, MySQL or any JDBC compatible database as a catalog.
Make sure to pass the right username and password for your database.
spark-sql --packages org.apache.iceberg:iceberg-spark-runtime-3.2_2.12:1.0.0 \
--conf spark.sql.catalog.my_catalog=org.apache.iceberg.spark.SparkCatalog \
--conf spark.sql.catalog.jdbc.warehouse=$WAREHOUSE \
--conf spark.sql.catalog.jdbc.catalog-impl=org.apache.iceberg.jdbc.JdbcCatalog \
--conf spark.sql.catalog.jdbc.uri=$URI \
--conf spark.sql.catalog.jdbc.jdbc.verifyServerCertificate=true \
--conf spark.sql.catalog.jdbc.jdbc.useSSL=true \
--conf spark.sql.catalog.jdbc.jdbc.user=$DB_USERNAME \
--conf spark.sql.catalog.jdbc.jdbc.password=$DB_PASSWORD
Conclusion
Once you've configured your Spark session keep in mind you must use the configured namespace for all queries. For example if I configured the catalog with:
--conf spark.sql.catalog.mycoolcatalog.catalog-impl=org.apache.iceberg.jdbc.JdbcCatalog \
Then creating a table would look like:
CREATE TABLE mycoolcatalog.table1 (name STRING) USING iceberg;
Aside from that consult the Iceberg Documentation or this Apache Iceberg 101 article for more information.