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Scylla-Migrator

https://www.scylladb.com/ ScyllaDB (10130) scylladb/scylla-migrator (10)
Languages:Python, CQL
Templates:Cassandra
License:Apache 2.0

Building

Make sure sbt is installed on your machine, and run build.sh.

Configuring the Migrator

Create a config.yaml for your migration using the template config.yaml in the repository root. Read the comments throughout carefully.

Running on a live Spark cluster

The Scylla Migrator is built against Spark 2.3.1, so you'll need to run that version on your cluster.

After running build.sh, copy the jar from ./target/scala-2.11/scylla-migrator-assembly-0.0.1.jar and the config.yaml you've created to the Spark master server.

Then, run this command on the Spark master server:

spark-submit --class com.scylladb.migrator.Migrator \
  --master spark://<spark-master-hostname>:7077 \
  --conf spark.scylla.config=<path to config.yaml> \
  <path to scylla-migrator-assembly-0.0.1.jar>

Running the validator

This project also includes an entrypoint for comparing the source table and the target table. You can launch it as so (after performing the previous steps):

spark-submit --class com.scylladb.migrator.Validator \
  --master spark://<spark-master-hostname>:7077 \
  --conf spark.scylla.config=<path to config.yaml> \
  <path to scylla-migrator-assembly-0.0.1.jar>

Running locally

To run in the local Docker-based setup:

  1. First start the environment:

    docker-compose up -d
  2. Launch cqlsh in Cassandra's container and create a keyspace and a table with some data:

    docker-compose exec cassandra cqlsh
    <create stuff>
  3. Launch cqlsh in Scylla's container and create the destination keyspace and table with the same schema as the source table:

    docker-compose exec scylla cqlsh
    <create stuff>
  4. Edit the config.yaml file; note the comments throughout.
  5. Run build.sh.
  6. Then, launch spark-submit in the master's container to run the job:

    docker-compose exec spark-master spark-submit --class com.scylladb.migrator.Migrator \
    --master spark://spark-master:7077 \
    --conf spark.driver.host=spark-master \
    --conf spark.scylla.config=/app/config.yaml \
    /jars/scylla-migrator-assembly-0.0.1.jar

The spark-master container mounts the ./target/scala-2.11 dir on /jars and the repository root on /app. To update the jar with new code, just run build.sh and then run spark-submit again.

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