We're using a pre-built cloudera running on Azure, and whilst it seems to work quite well out of the box, there is one oddity that we've not yet figured out.
If you login to the cloudera manager, and click on the Impala service, then the queries tab, it never shows any completed queries. So it's hard to go and find the long running queries.
If you look whilst a query is actually running, you can see them in the list. So it seems to have some sort of very aggressive clearing down, but I can't find what parameter that might be.
The correction of hwclock time will resolve this issue