When you add a node to the Decision Data Store service, Pega Platform deploys a Cassandra database on that node. For nodes running the Windows operating system, Cassandra requires that the script execution policy be set to Unrestricted, which permits loading all files and running all scripts. If the execution policy is set to any other level while a node is added to the Decision Data Store, the operation fails and the JOIN_FAILED message is displayed. At the time of the failure, your application logs record a message similar to the following:

java.lang.RuntimeException: java.util.concurrent.ExecutionException: com.pega.pegarules.pub.PRRuntimeException: Cannot bootstrap cassandra
at com.google.common.base.Throwables.propagate(Throwables.java:160)
at com.pega.dsm.dnode.impl.stream.DataObservableImpl.await(DataObservableImpl.java:124)
at com.pega.dsm.dnode.impl.stream.DataObservableImpl.await(DataObservableImpl.java:88)
at com.pegarules.generated.activity.ra_action_pzasyncexecuteoperation_f8bc98ec5361bd113e14e2f210cd31d0.step1_circum0(ra_action_pzasyncexecuteoperation_f8bc98ec5361bd113e14e2f210cd31d0.java:160)
at com.pegarules.generated.activity.ra_action_pzasyncexecuteoperation_f8bc98ec5361bd113e14e2f210cd31d0.perform(ra_action_pzasyncexecuteoperation_f8bc98ec5361bd113e14e2f210cd31d0

Caused by: com.pega.dsm.dnode.api.DNodeException: Unable to start DDS. Process has exited with code: 0
WARNING! Powershell script execution unavailable.
Please use 'powershell Set-ExecutionPolicy Unrestricted'
on this user-account to run cassandra with fully featured
functionality on this platform.
Starting with legacy startup options
Starting Cassandra Server

1. In the PowerShell console of the failed node, enter Set-ExecutionPolicy Unrestricted
2. Remove the failed node from the Decision Data Store service:
   1. In the header of Dev Studio, click ConfigureDecisioningInfrastructureServicesDecision Data Store.
   2. In the Decision data store nodes section, locate the node that did not join the service as a result of an incorrect execution policy level.
   3. In the Action column for that node, click ExecuteDecommission.
3. Add the node back to the Decision Data Store service.
   For more information, see Assigning node types to nodes for on-premises environments and Configuring the Decision Data Store service.