@TADA As this is an older post, you would have a better chance of receiving a resolution by starting a new thread. This will also be an opportunity to provide details specific to your environment that could aid others in assisting you with a more accurate answer to your question. You can link this thread as a reference in your new post. ... View more

@ManjuN, Has the reply helped resolve your issue? If so, please mark the appropriate reply as the solution, as it will make it easier for others to find the answer in the future.  If you are still experiencing the issue, can you provide the information @Asok  has requested? ... View more

Hi @ManjuN ,   NoClassDefFoundError Is usually seen when required jar is missing. In this case atlas migration script is looking for a jar which contains class "com/tinkerpop/blueprints/Graph". This class definition is available in blueprints-core-2.6.0.jar which is available on HDP-2.6.x.     # jar -tf /usr/hdp/2.6.<version>/atlas/server/webapp/atlas/WEB-INF/lib/blueprints-core-2.6.0.jar | grep -i "com/tinkerpop/blueprints/Graph" com/tinkerpop/blueprints/Graph.class com/tinkerpop/blueprints/GraphFactory.class com/tinkerpop/blueprints/GraphQuery.class       In your case, you are running a migration script from "3.1.0.0-78" directory and that is the reason you are getting NoClassDefFoundError.     python /usr/hdp/3.1.0.0-78/atlas/tools/migration-exporter/atlas_migration_export.py -d /atlas_metadata       Steps in the document needs to be performed only if you are upgrading your cluster from 2.6.x to 3.0+ version, because In HDP-3.0+, Apache Atlas uses the JanusGraph graph database to store metadata objects whereas in earlier versions, Atlas used the Titan graph database for metadata storage.   The document says, "Before upgrading HDP and Atlas, perform the following steps on the HDP-2.x cluster".   If you are performing this step during a major upgrade (from HDP-2.6.x to HDP3.0+ or 2.6.5 to HDP-7.x), kindly run atlas_migration_export.py script from 2.6.x path. For minor versions, this step is not required. ... View more