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Support Article

Error on adding Decision Data Store nodes




Error occurs on adding Decision Data Store nodes using the Decisioning Services landing page. The status of the newly added nodes is reported as 'joining failed'.

Error Messages


SessionNotAvailableException: Unable to obtain session. Cassandra hasn't been started or is unavailable
Caused by:com.datastax.driver.core.exceptions.AuthenticationException: Authentication error on host Username and/or password are incorrect


Steps to Reproduce

  1. Add Decision Data Store nodes using the Decisioning Services landing page 
  2. Wait for the nodes to join
  3. Perform a Refresh. The status of the online nodes displays as 'joining failed' and the error occurs in the PegaRULES logs

Root Cause

A software use or operation error. The user configured the external Cassandra nodes. Hence, the Cassandra credentials changed. The wrong credentials were used on adding the local nodes.


Perform the following local-change:
Revert the Cassandra credentials to the below default values:
  • Cassandra user ID: dnode_ext
  • Cassandra password: dnode_ext



Published April 3, 2019 - Updated December 2, 2021

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