DataStax Enterprise times out when starting 

When starting DataStax Enterprise as a service a timed out message is displayed.

The DataStax Enterprise Help Center also provides troubleshooting information.

When starting DataStax Enterprise (DSE) as a service, a script sets up the environment and launches the service. After the DSE service is launched, the script verifies if the service is running. The service takes a few seconds to start, and might display:
WARNING: Timed out while waiting for DSE to start. 

This error does not necessarily mean that the DSE service failed to start. Verify by checking the log files in /var/log/cassandra/system.out.

The start script checks if the DSE service is running once per second, so the number of checks is equal to the number of seconds.

To increase the time until the service is declared not to launch successfully, uncomment and edit the WAIT_FOR_START option in the /etc/default/dse file, and then restart the DataStax Enterprise:
# Uncomment if you want longer/shorter waits checking if the service is up