This is likely because hdfs's core-site.xml (or something similar) provides
an "fs.default.name" which changes the default FileSystem and Spark uses
the Hadoop FileSystem API to resolve paths. Anyway, your solution is
definitely a good one -- another would be to remote hdfs from Spark's
classpath if you didn't want it, or to specify an overriding fs.default.name
.
On Thu, Apr 10, 2014 at 2:30 PM, didata.us <subscripti...@didata.us> wrote:
> Hi:
>
> I believe I figured out how the behavior here:
>
> A file specified to SparkContext like this '*/path/to/some/file*':
>
> - Will be interpreted as '*hdfs://*path/to/some/file', when settings
> for HDFS are present in '*/etc/hadoop/conf/*-site.xml*'.
> - Will be interpreted as '*file:///*path/to/some/file', (i.e. locally)
> otherwise.
>
> I confirmed this behavior by temporarily doing this:
>
> - user$ sudo mv /etc/hadoop/conf /etc/hadoop/conf_
>
> after which I re-ran my commands below. This time the SparkContext did,
> indeed, look for and found, the file locally.
>
> In summary, '*/path/to/some/file*' is interpreted as an in-HDFS relative
> path when a HDFS configuration is found; and interpreted as an absolute
> local UNIX file path when a HDFS configuration is *not* found.
>
> To be on the safe side, it's probably best to qualify local files with '
> *file:///*' when that is what's intended; ahd with 'hdfs://' when HDFS is
> what's intended.
>
> Hopes this helps someone. :)
>
> ---
> Sincerely,
> Noel M. Vega
> DiData
> www.didata.us
>
> On 2014-04-10 14:53, DiData wrote:
>
> Hi Alton:
>
> Thanks for the reply. I just wanted to build/use it from scratch to get a
> better intuition of what's a happening.
>
> Btw, using the binaries provided by Cloudera/CDH5 yielded the same issue
> as my compiled version (i.e. it, too,
> tried to access the HDFS / Name Node. Same exact error).
>
> However, a small breakthrough. Just now I tinkered some more and found
> that this variation works:
>
> REPLACE THIS: >>> distData =
> sc.textFile('/home/user/Download/ml-10M100K/ratings.dat') WITH THIS:
> >>>distData = sc.textFile('
> *file:///*home/user/Download/ml-10M100K/ratings.dat') That is, use '
> file:///'. I don't know if that is the correct way of specifying the URI
> for local files, or whether this just *happens to work*. The documents that
> I've read thus far haven't shown it that specified way, but I still have
> more to read.
>
> =:)
>
>
> Thank you,
>
> ~NMV
>
>
> On 04/10/2014 04:20 PM, Alton Alexander wrote:
>
> I am doing the exact same thing for the purpose of learning. I also
> don't have a hadoop cluster and plan to scale on ec2 as soon as I get
> it working locally.
>
> I am having good success just using the binaries on and not compiling
> from source... Is there a reason why you aren't just using the
> binaries?
>
> On Thu, Apr 10, 2014 at 1:30 PM, DiData <subscripti...@didata.us>
> <subscripti...@didata.us> wrote:
>
> Hello friends:
>
> I recently compiled and installed Spark v0.9 from the Apache distribution.
>
> Note: I have the Cloudera/CDH5 Spark RPMs co-installed as well (actually,
> the
> entire big-data suite from CDH is installed), but for the moment I'm using
> my
> manually built Apache Spark for 'ground-up' learning purposes.
>
> Now, prior to compilation (i.e. 'sbt/sbt clean compile') I specified the
> following:
>
> export SPARK_YARN=true
> export SPARK_HADOOP_VERSION=2.3.0-cdh5.0.0
>
> The resulting examples ran fine locally as well as on YARN.
>
> I'm not interested in YARN here; just mentioning it for completeness in case
> that matters in
> my upcoming question. Here is my issue / question:
>
> I start pyspark locally -- on one machine for API learning purposes -- as
> shown below, and attempt to
> interact with a local text file (not in HDFS). Unfortunately, the
> SparkContext (sc) tries to connect to
> a HDFS Name Node (which I don't currently have enabled because I don't need
> it).
>
> The SparkContext cleverly inspects the configurations in my
> '/etc/hadoop/conf/' directory to learn
> where my Name Node is, however I don't want it to do that in this case. I
> just want it to run a
> one-machine local version of 'pyspark'.
>
> Did I miss something in my invocation/use of 'pyspark' below? Do I need to
> add something else?
>
> (Btw: I searched but could not find any solutions, and the documentation,
> while good, doesn't
> quite get me there).
>
> See below, and thank you all in advance!
>
>
> user$ export PYSPARK_PYTHON=/usr/bin/bpython
> user$ export MASTER=local[8]
> user$ /home/user/APPS.d/SPARK.d/latest/bin/pyspark
> #
> ===========================================================================================
> >>> sc
> <pyspark.context.SparkContext object at 0x24f0f50>
> >>>
> >>> distData = sc.textFile('/home/user/Download/ml-10M100K/ratings.dat')
> >>> distData.count()
> [ ... snip ... ]
> Py4JJavaError: An error occurred while calling o21.collect.
> : java.net.ConnectException: Call From server01/192.168.0.15 to
> namenode:8020 failed on connection exception:
> java.net.ConnectException: Connection refused; For more details
> see:http://wiki.apache.org/hadoop/ConnectionRefused
> [ ... snip ... ]
> >>>
> >>>
> #
> ===========================================================================================
>
> --
> Sincerely,
> DiData
>
>
> --
> Sincerely,
> DiData
>
>
