docker-spark-ipython

To run a container with a shared folder (e.g. ~/Desktop/localFolder), listening on the port 8888. The localFolder is located on the desktop and you can use it to share file with the virtual machines, ipython notebook included.

docker run -d -p 8888:8888 -v ~/Desktop/localFolder/:/notebooks --name pyspark stravanni/cineca-spark

• -d deamon mode
• -p posrt
• -v volume
• --name give a name to the containers

Launch the notebook

Open the brawser at localhost:8888

If you are on Mac, remember that the actual VB ip can be finded with boot2docker ip. While, if you want connect to the localhost you need the following port forwarding for VBox:

(e.g. ports from 8880 to 8890)

for i in {8880..8890}; do
VBoxManage modifyvm "boot2docker-vm" --natpf1 "tcp-port$i,tcp,,$i,,$i";
VBoxManage modifyvm "boot2docker-vm" --natpf1 "udp-port$i,udp,,$i,,$i";
done

To get info about the virtual machine where the containers run:

boot2docker info

To change the memory of the VirtualMachine (i.e. VBox)

BoxManage modifyvm boot2docker-vm --memory 4096

Manage containers

• docker ps shows acrive conainers
• docker ps -a shows all containers
• docker restart CONTAINER-ID restarts a container
• docker stop 'docker ps -aq' stops all containers
• docker rm 'docker ps -aq' removes all conainers

IPython and PySpark

Launching the container the first command issued is:

IPYTHON_OPTS="notebook --no-browser --ip=0.0.0.0 --port 8888" /usr/local/spark/bin/pyspark

The IPython notebook will already have the sparkContext variable sc. Write sc.version to see what verison is loaded.

Hadoop environment

To read a file directly from the disk (no HDFS), use explicitly:

sc.textFile("file:///absolute_path to the file/")

SparkContext.textFile internally calls org.apache.hadoop.mapred.FileInputFormat.getSplits, which in turn uses org.apache.hadoop.fs.getDefaultUri if schema is absent. This method reads "fs.defaultFS" parameter of Hadoop conf.

If you set HADOOP_CONF_DIR environment variable, the parameter is usually set as "hdfs://..."; otherwise "file://".