I have been looking at http://hbase.apache.org/notsoquick.html#hadoop
which does NOT have that citation. So I never saw that before now. It is indeed helpful. But: must we really spend hours on flaky tests while building? Also, it would comfort noobs like me if there were a bit of explanation relating to the hadoop build instructions, which confusingly seem to sometimes build native binaries and sometimes not. Note: the remark that "You have to replace it if you are running on an hadoop that is other than an exact match to the jar we ship with" suggests one could (if "exact match") go down the very path that we are trying to discourage (even when "exact match"). This is what I tried, and was then told is not reliable, then was told might work, but nobody was willing to tell me whether or how I could be sure it would work. So my suggestion is to be unequivocal about it: when running distributed, always build your own Hadoop and put its -core JAR into your HBase installation (or use Cloudera, which has done this for you). Also: explicitly explain how the file has to be named (there is a strict naming requirement so that the launching scripts work, right?). Regards, Mike Spreitzer From: stack <[email protected]> To: Mike Spreitzer/Watson/IBM@IBMUS Cc: [email protected] Date: 06/06/2011 10:58 PM Subject: Re: Hadoop not working after replacing hadoop-core.jar with hadoop-core-append.jar On Mon, Jun 6, 2011 at 6:49 PM, Mike Spreitzer <[email protected]> wrote: > Where is that citation of Michael Noll's nicely detailed instruction on how > to build the append branch? > See Section 1.3.1.2 here http://hbase.apache.org/book/notsoquick.html#requirements. Look for "Michael Noll has written a detailed blog, Building an Hadoop 0.20.x version for HBase 0.90.2, on how to build an Hadoop from branch-0.20-append. Recommended." > Why does hbase include a hadoop-core.jar? The instructions say I should > replace it, so why am I given it in the first place? > You have to replace it if you are running on an hadoop that is other than an exact match to the jar we ship with (If you are doing standalone mode or if you are running unit tests, the jar is needed since we have a bunch of Hadoop dependencies from our Configuration to UI to MapReduce to Connection to HDFS etc.) Again, I apologize for the fact that this is less-than smooth sailing. HBase project is in a bit of an awkward spot. We're trying to put the best face on it. If you have any suggestions for how best we might this, we are all ears. Yours, St.Ack
