Cloudera Docs

Importing Confluent Schema Registry schemas into Cloudera Schema Registry

If you are migrating away from Confluent's Schema Registry, you can use the schema-import tool to import your schemas to the Cloudera Schema Registry service.

Confluent Schema Registry stores all schemas in a Kafka topic usually named _schemas. To import these schemas you must copy the content to a text file and upload to Cloudera's Schema Registry service.

You must have the export-import access policy with the Create permission assigned to your user account.

For more information on Schema Registry access policies, see Schema Registry Authorization through Ranger Access Policies

  1. Copy the contents of the Kafka topic (usually named _schemas), to a text file. Use the following command: 
    kafka-console-consumer --from-beginning --topic _schemas --formatter kafka.tools.DefaultMessageFormatter --property print.key=true --property print.value=true --bootstrap-server `hostname`:9092
    Here is an example of a text file with the contents of the Kafka topic: 
    {"keytype":"SCHEMA","subject":"Kafka-key","version":1,"magic":1}        {"subject":"Kafka-key","version":1,"id":1,"schema":"\"string\"","deleted":false}
{"keytype":"SCHEMA","subject":"Car","version":1,"magic":1}      {"subject":"Car","version":1,"id":2,"schema":"{\"type\":\"record\",\"name\":\"Car\",\"namespace\":\"com.cloudera\",\"fields\":[{\"name\":\"model\",\"type\":\"string\"},{\"name\":\"color\",\"type\":\"string\",\"default\":\"blue\"},{\"name\":\"price\",\"type\":\"string\",\"default\":\"0\"},{\"name\":\"year\",\"type\":[\"null\",\"string\"],\"default\":null}]}","deleted":false}
{"keytype":"SCHEMA","subject":"Car","version":2,"magic":1}      {"subject":"Car","version":2,"id":3,"schema":"{\"type\":\"record\",\"name\":\"Car\",\"namespace\":\"com.cloudera\",\"fields\":[{\"name\":\"model\",\"type\":\"string\"},{\"name\":\"color\",\"type\":\"string\",\"default\":\"blue\"},{\"name\":\"price\",\"type\":\"string\",\"default\":\"0\"}]}","deleted":false}
  2. Upload the text file to Cloudera's Schema Registry service using the following endpoint: /api/v1/schemaregistry/import
    Use the following command: 
    curl -u : --negotiate --form file='@<filename>' http://`hostname`:7788/api/v1/schemaregistry/import?format=1&failOnError=true
    Where:
    • format: Can be 0 or 1. However, for schema content from Confluent, the file must be 1.
    • failOnError=true: This setting is useful if the process fails to import all the schemas when one or more schemas already exist in the target Schema Registry.
    • file='<filename>: Enter the name of the file.
    Here is an example of the command: 
    curl -u : --negotiate --form file='@schemadump.json' http://`hostname`:7788/api/v1/schemaregistry/import?format=1&failOnError=true
    Here is an example of the response: 
    {"successCount":45,"failedCount":0,"failedIds":[]}