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, 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 content of the Kafka topic (usually named _schemas) to a text file using 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
    The following is an example of a text file with the content 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 by 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,
    file='<filename>'
    Enter the name of the file.
    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.
    The following is an example of the command: 
    curl -u : --negotiate --form file='@schemadump.json' http://`hostname`:7788/api/v1/schemaregistry/import?format=1&failOnError=true
    The following is an example of the response: 
    {"successCount":45,"failedCount":0,"failedIds":[]}