Re ran the tests last night and only one (new) test failed :
[junit] Test org.apache.hadoop.metrics2.impl.TestMetricsSystemImpl FAILED
So I assume the GangliaMetrics test was fixed by the hosts file too.
I found MAPREDUCE-3894 which seems to explain the failure and it suggests its intermittent. I've tested this by rerunning just that test and low and behold it passed :
# ant test -Dtestcase=TestMetricsSystemImpl
# BUILD SUCCESSFUL
# Total time: 24 seconds
Finally, a clean test run (even with my patch attached). Now I just need someone to look at / approve my patch:
Any clue as to how I draw someones attention to this?