问题
How is the Spark master elected in a Datastax Enterprise cluster? I have looked at the configurations in /etc/dse/dse-env.sh and /etc/dse/spark/spark-defaults.conf and /etc/dse/spark/spark-env.sh. But I cannot find it any of those locations?
On our cluster the Spark master keeps on moving from one node to another after the restart of the services?
回答1:
In DSE 4.6, the Spark Master / Hadoop Job Tracker (always on the same node) are determined by a round robin algorithm and are stored in jobtracker table. This may change in future releases.
You can check and see what your current master is is by using:
dsetool listjt
This will output your current master and the reserve master if one has been configured.
To configure a reserve master use:
dsetool reservejt
Output might look something like this:
$ dsetool listjt DC JobTracker
-- --
Analytics-Analytics 192.168.101.122
------ Reserve-JT = 192.168.101.121
来源：https://stackoverflow.com/questions/29558584/how-is-the-spark-master-elected-in-a-datastax-enterprise-cluster