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diff --git a/R/README.md b/R/README.md new file mode 100644 index 0000000000..a6970e39b5 --- /dev/null +++ b/R/README.md @@ -0,0 +1,67 @@ +# R on Spark + +SparkR is an R package that provides a light-weight frontend to use Spark from R. + +### SparkR development + +#### Build Spark + +Build Spark with [Maven](http://spark.apache.org/docs/latest/building-spark.html#building-with-buildmvn) and include the `-PsparkR` profile to build the R package. For example to use the default Hadoop versions you can run +``` + build/mvn -DskipTests -Psparkr package +``` + +#### Running sparkR + +You can start using SparkR by launching the SparkR shell with + + ./bin/sparkR + +The `sparkR` script automatically creates a SparkContext with Spark by default in +local mode. To specify the Spark master of a cluster for the automatically created +SparkContext, you can run + + ./bin/sparkR --master "local[2]" + +To set other options like driver memory, executor memory etc. you can pass in the [spark-submit](http://spark.apache.org/docs/latest/submitting-applications.html) arguments to `./bin/sparkR` + +#### Using SparkR from RStudio + +If you wish to use SparkR from RStudio or other R frontends you will need to set some environment variables which point SparkR to your Spark installation. For example +``` +# Set this to where Spark is installed +Sys.setenv(SPARK_HOME="/Users/shivaram/spark") +# This line loads SparkR from the installed directory +.libPaths(c(file.path(Sys.getenv("SPARK_HOME"), "R", "lib"), .libPaths())) +library(SparkR) +sc <- sparkR.init(master="local") +``` + +#### Making changes to SparkR + +The [instructions](https://cwiki.apache.org/confluence/display/SPARK/Contributing+to+Spark) for making contributions to Spark also apply to SparkR. +If you only make R file changes (i.e. no Scala changes) then you can just re-install the R package using `R/install-dev.sh` and test your changes. +Once you have made your changes, please include unit tests for them and run existing unit tests using the `run-tests.sh` script as described below. + +#### Generating documentation + +The SparkR documentation (Rd files and HTML files) are not a part of the source repository. To generate them you can run the script `R/create-docs.sh`. This script uses `devtools` and `knitr` to generate the docs and these packages need to be installed on the machine before using the script. + +### Examples, Unit tests + +SparkR comes with several sample programs in the `examples/src/main/r` directory. +To run one of them, use `./bin/sparkR <filename> <args>`. For example: + + ./bin/sparkR examples/src/main/r/pi.R local[2] + +You can also run the unit-tests for SparkR by running (you need to install the [testthat](http://cran.r-project.org/web/packages/testthat/index.html) package first): + + R -e 'install.packages("testthat", repos="http://cran.us.r-project.org")' + ./R/run-tests.sh + +### Running on YARN +The `./bin/spark-submit` and `./bin/sparkR` can also be used to submit jobs to YARN clusters. You will need to set YARN conf dir before doing so. For example on CDH you can run +``` +export YARN_CONF_DIR=/etc/hadoop/conf +./bin/spark-submit --master yarn examples/src/main/r/pi.R 4 +``` |