Support Article
Cassandra does not run when Temp directory is removed
SA-84220
Summary
On removing the Temp directory from the default Cassandra Pega Temp directory, Cassandra stops executing.
Error Messages
Not Applicable
Steps to Reproduce
- Install Pega Platform including Cassandra and Kafka.
- Delete the Temp directory contents.
Root Cause
The Pega application contains the appropriate Distribution files for Cassandra and Kafka. Cassandra and Kafka are both installed when the respective Decision Data Store (DDS) and Stream services are launched on node startup. Neither require the reinstallation of the Pega application.
The location of the Cassandra and Kafka Installation directories is application server-specific.
For example, when executing the Pega application from within Apache Tomcat, the Installation directories for Cassandra and Kafka are in the Tomcat home directory. With other application server types, the Installation location is the Pega Temp directory.
The user can add the node/cassandra_data_directory configuration property to specify the location of the Cassandra data.
The Cassandra data is stored in the cassandra_data directory and is stored in one location only. Hence, it is deleted and must be repopulated.
Resolution
The location of the Cassandra and Kafka installation directories is application server-specific.
Use the following prconfig.xml property to configure the location in which to unpack the Kafka distribution:
- a. Add the below entry in the prconfig.xml file.
<env name="dsm/services/stream/pyUnpackBasePath" value="/opt/kafka" >
- Create a Dynamic System Setting (DSS) with the following options:
Owning Ruleset - Pega-Engine
Setting Purpose - prconfig/dsm/services/stream/pyUnpackBasePath/default
Value - /opt/kafka
To change the Apache Kafka distribution location, refer to: https://community.pega.com/knowledgebase/articles/decision-management-overview/advanced-configurations-stream-service
For more information about Kafka standard deployment, refer to: https://community.pega.com/knowledgebase/articles/decision-management-overview/kafka-standard-deployment
Published August 6, 2020 - Updated December 2, 2021
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