Installing Hadoop on Ubuntu 11.10 Oneiric Ocelot

Just a quick tip if you try to set up Hadoop on your Ubuntu 11.10 and you wonder if Maverick’s version will work – yes, it will. Just follow the installation guide inserting this:

deb http://archive.cloudera.com/debian maverick-cdh3 contrib
deb-src http://archive.cloudera.com/debian maverick-cdh3 contrib

in /etc/apt/sources.list.d/cloudera.list – that’s it!

OK, not exactely – some people (I was one of them) report a NullPointer Exception. Something similar to this:

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Error: java.lang.NullPointerException
        at java.util.concurrent.ConcurrentHashMap.
            get(ConcurrentHashMap.java:768)
        at org.apache.hadoop.mapred.ReduceTask$
            ReduceCopier$GetMapEventsThread.
            getMapCompletionEvents(ReduceTask.java:2683)
        at org.apache.hadoop.mapred.
            ReduceTask$ReduceCopier$GetMapEventsThread.
            run(ReduceTask.java:2605)

check your Hadoop host settings (preferrably use IP instead of hostname) and/or /etc/hosts, which may contain a strange entry with something like .(null) – just leave one, proper hostname in that line. For me – it started to work after this fix.

I won’t risk saying that it’ll be OK for production enviroment (production server with Ubuntu? OK…), but for testing – it works perfectly.