Starting Hadoop, R studio and Rhadoop
We need to quickly check whether everything is working in our virtual machine and to become familiar with the environment we will be working with.
Open the terminal by clicking on the black icon on the bottom left and type
start-dfs.sh start-yarn.sh hadoop fs -ls
to open the Rstudio GUI. We should open an Rscript file and save it to the local or any other folder up to our choice. Next we should set up system variables by copying the following lines into the script file and execute them:
Sys.setenv(HADOOP_OPTS="-Djava.library.path=/usr/local/hadoop/lib/native") Sys.setenv(HADOOP_HOME="/usr/local/hadoop") Sys.setenv(HADOOP_CMD="/usr/local/hadoop/bin/hadoop") Sys.setenv(HADOOP_STREAMING="/usr/local/hadoop/share/hadoop/tools/lib/hadoop-streaming-2.6.5.jar") Sys.setenv(JAVA_HOME="/usr/lib/jvm/java-8-openjdk-amd64")
We load RHadoop by loading the libraries
rmr2 and executing
library(rhdfs) library(rmr2) hdfs.init()
You might see the log and some warning messages, but no filesystem errors while executing the above commands. There might be some glyph rendering errors, which we can simply ignore.
Try to quit and stop the Hadoop servers by using counterpart commands
stop-dfs.sh in terminal.
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