Hadoop datanode process listens on random port on localhost

Question

Each datanode process in my hadoop cluster is listening to 4 ports. 3 of them are well known (50010, 50020, 50075) but the 4th one, is chosen at random and bound to localhost. Can anyone shed some light on what is using this port and is this a configurable parameter?

Here are the relevant lines from the datanode log file:

2018-01-17 08:42:58,239 INFO org.apache.hadoop.http.HttpServer2: Jetty bound to port 23209
2018-01-17 08:42:58,239 INFO org.mortbay.log: jetty-6.1.26
2018-01-17 08:42:58,364 INFO org.mortbay.log: Started HttpServer2$SelectChannelConnectorWithSafeStartup@localhost:23209

boogie boogie · Accepted Answer · 2018-01-22T06:48:02

OK .... turns out it's the datanode's netty reverse-proxy port and it's still unconfigurable but a patch is coming to make it so: https://issues.apache.org/jira/browse/HDFS-9049

Hadoop datanode process listens on random port on localhost

1 Answers