question

Logging

Since DataStax Desktop runs DSE in a docker container, you will need to view the Docker logs in order to determine why the container is in an error state.

For example, to view the logs for the DSE server container:

$ docker logs dse-dse-server

For details, see the Docker documentation on Viewing logs for a container or service.

Root cause

You didn't provide a lot of information but I suspect you are seeing the following on the DataStax Desktop console:

4. DataStax Enterprise 6.8 stack started
Stack was started but is now in an error state.

In my experience, the most common cause of this issue is insufficient memory allocated to Docker. In the container logs you will see an error similar to this:

ERROR [DSE main thread] 2020-12-14 05:09:38,734  DseDaemon.java:562 - Unable to start DSE server.
java.lang.ExceptionInInitializerError: null
    at com.datastax.bdp.plugin.SparkPlugin.isEnabled(SparkPlugin.scala:94)
    at com.datastax.bdp.plugin.PluginManager.isPluginEnabled(PluginManager.java:428)
    at com.datastax.bdp.plugin.PluginManager.shouldActivatePlugin(PluginManager.java:388)
    ...
Caused by: org.apache.commons.configuration.ConfigurationRuntimeException: Failed to read worker_options
    at com.datastax.bdp.config.DseWorkerResourcesConfigResolver.convert(DseWorkerResourcesConfigResolver.scala:117)
    at com.datastax.bdp.config.ConfigUtil$ParamResolver.initialize(ConfigUtil.java:91)
    at com.datastax.bdp.config.ConfigUtil$ParamResolver.check(ConfigUtil.java:137)
    at com.datastax.bdp.config.DseSparkConfig.<clinit>(DseSparkConfig.java:212)
    ...
Caused by: org.apache.commons.configuration.ConfigurationRuntimeException: Please either increase the alwayson_sql workpool memory in dse.yaml to at least 0.2934 or decrease the spark.executor.memory in spark-alwayson-sql.conf to at most AlwaysOn SQL workpool memory in 872M
    at com.datastax.bdp.config.DseWorkerResourcesConfigResolver.convert(DseWorkerResourcesConfigResolver.scala:85)
    ...

Solution

Increase the amount of memory allocated to Docker resources. We recommend you allocate at least 10GB (16GB is preferred).

For details on configuring Docker Desktop for Mac, see the Resources section of the user manual.

Alternatives

If you just want to be able to try out DSE or Apache Cassandra, a better option is to just use DataStax Astra. It's FREE forever with no credit card required. You'll be able to launch a cluster with a just few clicks and ready to use in a couple of minutes. Cheers!