Day 4 Lab1: Docker container for Kafka - Spark streaming - - - PDF document

Day 4 – Lab1:

Docker container for Kafka - Spark streaming - Cassandra

This Dockerfile sets up a complete streaming environment for experimenting with Kafka, Spark streaming (PySpark), and Cassandra. It installs

• Kafka 0.10.2.1
• Spark 2.1.1 for Scala 2.11
• Cassandra 3.7

It additionnally installs

• Anaconda distribution 4.4.0 for Python 2.7.10
• Jupyter notebook for Python

Quick start-up guide

Run container using DockerHub image

docker run -p 4040:4040 -p 8888:8888 -p 23:22 -ti --privileged yannael/kafka- sparkstreaming-cassandra

Note that any changes you make in the notebook will be lost once you exit the

• container. To keep the changes, it is necessary to put your notebooks in a folder on your

host, that you share with the container, using for example

docker run -v `pwd`:/home/guest/host -p 4040:4040 -p 8888:8888 -p 23:22 -ti -- privileged yannael/kafka-sparkstreaming-cassandra

Note:

• The "-v pwd:/home/guest/host" shares the local folder (i.e. folder containing

Dockerfile, ipynb files, etc...) on your computer - the 'host') with the container in the '/home/guest/host' folder.

• Port are shared as follows:
• 4040 bridges to Spark UI
• 8888 bridges to the Jupyter Notebook
• 23 bridges to SSH

SSH allows to get a connection to the container

ssh -p 23 guest@containerIP

where 'containerIP' is the IP of the container (127.0.0.1 on Linux). Password is 'guest'.

Start services

Once run, you are logged in as root in the container. Run the startup_script.sh (in /usr/bin) to start

• SSH server. You can connect to the container using user 'guest' and password

'guest'

• Cassandra
• Zookeeper server
• Kafka server

startup_script.sh

Connect, create Cassandra table, open notebook and start streaming

Connect as user 'guest' and go to 'host' folder (shared with the host)

su guest

Start Jupyter notebook

notebook

and connect from your browser at port host:8888 (where 'host' is the IP for your host. If run locally on your computer, this should be 127.0.0.1 or 192.168.99.100, check Docker documentation)

Start Kafka producer Open kafkaSendDataPy.ipynb and run all cells. Start Kafka receiver Open kafkaReceiveAndSaveToCassandraPy.ipynb and run cells up to start streaming. Check in subsequent cells that Cassandra collects data properly. Connect to Spark UI It is available in your browser at port 4040

Container configuration details

The container is based on CentOS 6 Linux distribution. The main steps of the building process are

• Install some common Linux tools (wget, unzip, tar, ssh tools, ...), and Java (1.8)
• Create a guest user (UID important for sharing folders with host!, see below), and

install Spark and sbt, Kafka, Anaconda and Jupyter notbooks for the guest user

• Go back to root user, and install startup script (for starting SSH and Cassandra

services), sentenv.sh script to set up environment variables (JAVA, Kafka, Spark, ...), spark-default.conf, and Cassandra

User UID

In the Dockerfile, the line

RUN useradd guest -u 1000

creates the user under which the container will be run as a guest user. The username is 'guest', with password 'guest', and the '-u' parameter sets the linux UID for that user.

In order to make sharing of folders easier between the container and your host, make sure this UID matches your user UID on the host. You can see what your host UID is with

echo $UID

Build and running the container from scratch

Clone this repository

git clone https://github.com/Yannael/kafka-sparkstreaming-cassandra

Build

From Dockerfile folder, run

docker build -t kafka-sparkstreaming-cassandra.

It may take about 30 minutes to complete.

Run

docker run -v `pwd`:/home/guest/host -p 4040:4040 -p 8888:8888 -p 23:22 -ti -- privileged kafka-sparkstreaming-cassandra