R Interpreter for Apache Zeppelin
R is a free software environment for statistical computing and graphics.
To run R code and visualize plots in Apache Zeppelin, you will need R on your master node (or your dev laptop).
- For Centos:
yum install R R-devel libcurl-devel openssl-devel
- For Ubuntu:
apt-get install r-base
Validate your installation with a simple R command:
R -e "print(1+1)"
To enjoy plots, install additional libraries with:
R -e "install.packages('devtools', repos = 'http://cran.us.r-project.org')"
R -e "install.packages('knitr', repos = 'http://cran.us.r-project.org')"
R -e "install.packages('ggplot2', repos = 'http://cran.us.r-project.org')"
Other visualization libraries:
R -e "install.packages(c('devtools','mplot', 'googleVis'), repos = 'http://cran.us.r-project.org'); require(devtools); install_github('ramnathv/rCharts')"
We recommend you to also install the following optional R libraries for happy data analytics:
To run Zeppelin with the R Interpreter, the
SPARK_HOME environment variable must be set. The best way to do this is by editing
If it is not set, the R Interpreter will not be able to interface with Spark.
You should also copy
conf/zeppelin-site.xml. That will ensure that Zeppelin sees the R Interpreter the first time it starts up.
Using the R Interpreter
By default, the R Interpreter appears as two Zeppelin Interpreters,
%r will behave like an ordinary REPL. You can execute commands as in the CLI.
R base plotting is fully supported
If you return a data.frame, Zeppelin will attempt to display it using Zeppelin's built-in visualizations.
%knitr interfaces directly against
knitr, with chunk options on the first line:
The two interpreters share the same environment. If you define a variable from
%r, it will be within-scope if you then make a call using
Using SparkR & Moving Between Languages
SPARK_HOME is set, the
SparkR package will be loaded automatically:
The Spark Context and SQL Context are created and injected into the local environment automatically as
The same context are shared with the
You can also make an ordinary R variable accessible in scala and Python:
And vice versa:
Caveats & Troubleshooting
Almost all issues with the R interpreter turned out to be caused by an incorrectly set
SPARK_HOME. The R interpreter must load a version of the
SparkRpackage that matches the running version of Spark, and it does this by searching
SPARK_HOME. If Zeppelin isn't configured to interface with Spark in
SPARK_HOME, the R interpreter will not be able to connect to Spark.
knitrenvironment is persistent. If you run a chunk from Zeppelin that changes a variable, then run the same chunk again, the variable has already been changed. Use immutable variables.
%rare two different ways of calling the same interpreter, as are
%knitr. By default, Zeppelin puts the R interpreters in the
%rinterpreter, if you return a data.frame, HTML, or an image, it will dominate the result. So if you execute three commands, and one is
hist(), all you will see is the histogram, not the results of the other commands. This is a Zeppelin limitation.
If you return a data.frame (for instance, from calling
head()) from the
%spark.rinterpreter, it will be parsed by Zeppelin's built-in data visualization system.
rmarkdown? Why no
htmlwidgets? In order to support
htmlwidgets, which has indirect dependencies,
pandoc, which requires writing to and reading from disc. This makes it many times slower than
knitr, which can operate entirely in RAM.
shinywould require integrating a reverse-proxy into Zeppelin, which is a task.
Max OS X & case-insensitive filesystem. If you try to install on a case-insensitive filesystem, which is the Mac OS X default, maven can unintentionally delete the install directory because
Rbecome the same subdirectory.
unable to start device X11with the repl interpreter. Check your shell login scripts to see if they are adjusting the
DISPLAYenvironment variable. This is common on some operating systems as a workaround for ssh issues, but can interfere with R plotting.
akka Library Version or
TTransporterrors. This can happen if you try to run Zeppelin with a SPARK_HOME that has a version of Spark other than the one specified with
-Pspark-1.xwhen Zeppelin was compiled.