Visualizing NetFlow Data with Apache Kudu, Apache Impala (incubating), StreamSets Data Collector, and D3.js

NetFlow is a data format that reflects the IP statistics of all network interfaces interacting with a network router or switch. Netflow records can be generated and collected in near real-time for the purposes of cybersecurity, network quality of service, and capacity planning. For network and cybersecurity analysts interested in these data, being able to have fast, up-to-the second insights can mean faster threat detection and higher quality network service.

Ingesting data and making it immediately available for query in Hadoop has traditionally been difficult, requiring a complex architecture commonly known as the Lambda architecture. Lambda requires the coordination of two storage layers: the “speed layer” and the “batch layer”. The complexity of Lambda has put many real-time analytical use-cases out of reach for Hadoop.  However, with Kudu we can implement a new, simpler architecture that provides real-time inserts, fast analytics, and fast random access, all from a single storage layer. In this article, we are going to discuss how we can use Kudu, Impala, Apache Kafka, StreamSets Data Collector (SDC), and D3.js to visualize raw network traffic in the form of NetFlow in the v5 format.

The data will flow through the following stages:

  1. A UDP NetFlow simulator generates a stream of NetFlow events.
  2. A StreamSets Data Collector ingest pipeline consumes these events in real-time and persists them into Kafka. The pipeline then performs some in-stream transformations and then persists events into Kudu for analytics
  3. A D3 visualization then queries Kudu via Impala

Network Traffic Simulator to Kafka

The goal of this section is to simulate network traffic and send that data to Kafka.

Step-1: Install and Run StreamSets Data Collector

  1. Download the StreamSets Data Collector TGZ binary from here: Download Link, extract and run it:

    $ tar xvzf streamsets-datacollector-all-
    $ cd streamsets-datacollector-
    $ bin/streamsets dc
  2. Once you see the message “Running on URI : ‘http://localhost:18630′” , navigate to localhost:18630 on your favorite browser and use admin/admin as username/password

Step-2: Create a Pipeline from UDP Origin to Kafka Producer

  1. On the StreamSets Dashboard, click on “+ Create New Pipeline” and specify a name and a description for your pipeline.
  2. After setting Name=”UDP_Kafka_Producer” and Description=”Source data from UDP to Kafka”, click on the Save button.
  3. Once you’ve done this, a grid should appear on your screen with a few icons on the right hand side.
  4. Make sure the drop down selector reads ‘Origins’. The various icons below list the data sources that StreamSets can read from. Scroll down to find the icon that reads ‘UDP Source’, and drag the icon onto the StreamSets grid.
  5. Once the UDP Source is in place, click on it. In the Configuration Panel below, select the UDP tab and change the Data Format to NetFlow. Leave Port and all other settings with their default values.
  6. Now let’s create a Kafka Producer! Change the drop down selector on the right from “Origins” to “Destinations”, and drag the “Kafka Producer” onto the StreamSets grid
  7. In the Kafka producer configuration, select Kafka and change TopicName to “NETFLOW”
  8. Make sure that Data Format is “SDC Record”
  9. Now let’s connect “UDP Source” to “Kafka Producer” by dragging an arrow from the UDP Source to the Kafka Producer.

Finally, click in the background of the grid, then, in the bottom pane, Configuration, Error Records and set Error Records to Discard


Step-3: Test Data Transfer between Traffic Simulator and Kafka Producer”

  1. Start the kafka consumer by running the following command on the shell:

    $ kafka-console-consumer --zookeeper ... --topic NETFLOW --from-beginning
  2. Let’s now start the UDP_KafkaProducer by clicking on the Start button on the top right corner of the StreamSets Dashboard.
  3. Get here and dataset-3-raw-netflow here
  4. Start the Traffic Simulator by compiling and running the Java-based UDP client using the shell:

    $ javac
    $ java UDPClient dataset-3-raw-netflow
  5. Upon success, you should see something like this on your Kafka Consumer terminal and the visualization in StreamSets:

StreamSets Data Collector is now receiving the UDP data, parsing the NetFlow format, and sending it to Kafka in its own internal record format. Kafka can buffer the records while we build another pipeline to write them to Kudu.

Kafka to Kudu

The goal of this section is to read the data from Kafka and ingest into Kudu, performing some lightweight transformations along the way.


  1. Before proceeding further, you need to install Kudu and Impala-Kudu integration
  2. If you’re still in the UDP Kafka Producer pipeline, click the ‘Pipelines’ link (top left).
  3. Click on “+ Create New Pipeline” and set Name to “Kafka Consumer to Apache Kudu” and Description to “Loading data from kafka consumer to apache kudu”, click on the Save button
  4. Once you’ve done this, the SDC grid should appear on your screen with a few icons on the right hand side.
  5. Make sure the drop down selector reads ‘Origins’. Scroll down to find the icon that reads “Kafka Consumer”, and drag the icon onto the StreamSets canvas.

Once the Kafka consumer in place, click on it. In the configuration panel below, select the Kafka tab and change Data Format to “SDC Record”, and set the topic name to “NETFLOW” (Make sure it’s the same name as above)


Now let’s create Apache Kudu as a destination:

  1. On the drop down selector, select “destinations” and drag the “Apache Kudu” icon onto the Map
  2. Select the Kudu tab and enter the appropriate details for your cluster

    Kudu Masters={kudu master}
    Table Name=netflow

The word timestamp is reserved in Impala, so let’s rename the field. Set “Field to Column Mapping” to:

timestamp packet_timestamp

Now we’ll use a JavaScript Evaluator to convert Long TimeStamp to DateTime ISO String format which will be compatible with Kudu range partition queries. (Note this should be possible via a field converter in the future.) We’ll talk more about range partitions later below. For now, let’s draw a JavaScript Evaluator between Kafka Consumer and Apache Kudu.

  1. In the drop down selector, select “processors”. Drag the “JavaScript Evaluator ” icon and drop it in between the Kafka Consumer and Apache Kudu. Draw intermediate paths between Kafka Consumer-JavaScript Evaluator and JavaScript Evaluator-Kudu
  2. Select JavaScript tab and replace script with below given code:

    for(var i = 0; i < records.length; i++) {
      try {
        var convertedDate = new Date(records[i].value.timestamp);
      } catch (e) {
        error.write(records[i], e);


If everything you’ve done so far is correct is set, clicking on “validate” will return a success message

Step-2: Now let’s write data to Kudu

Start the impala-shell on your terminal, and copy paste the sql query listed below to create an empty table called “netflow


id string,
packet_timestamp string,
srcaddr string,
dstas string,
dstaddr_s string,
dstport int32,
dstaddr string,
srcaddr_s string,
tcp_flags string,
dPkts string,
tos string,
engineid string,
enginetype string,
srcas string,
packetid string,
nexthop_s string,
samplingmode string,
dst_mask string,
snmponput string,
length string,
flowseq string,
samplingint string,
readerId string,
snmpinput string,
src_mask string,
version string,
nexthop string,
uptime string,
dOctets string,
sender string,
proto string,
srcport int32)
DISTRIBUTE BY HASH(id) INTO 4 buckets, RANGE (packet_timestamp) SPLIT ROWS(('2015-05-01'), ('2015-05-02'), ('2015-05-03'), ('2015-05-05'))
'storage_handler' = 'com.cloudera.kudu.hive.KuduStorageHandler',
'kudu.table_name' = ‘netflow’,
'kudu.master_addresses' = '{kudu master}',
'kudu.key_columns' = 'id,packet_timestamp’


The table netflow is hash partitioned by the ‘id’ field which is a unique key and should result in the rows being uniformly distributed among buckets and thus cluster nodes. Hash partitioning provides us high throughput for writes because (provided enough buckets) all nodes will contain a hash partition. Hash partitioning also provides for read parallelism when scanning across many id values because all nodes which contain a hash partition will participate in the scan.

The table also has been range partitioned by time so that for queries scanning only a specific time slice can exclude tablets not containing relevant data. This should increase cluster parallelism for large scans (across days) while limiting overhead for small scans (single day). Range partitioning also ensures partition growth is not unbounded and queries don’t slow down as the volume of data stored in the table grows, because we would be querying only certain portion of data and data is distributed across nodes by hash and range partitions.

The above table creation schema creates 16 tablets; first it creates 4 buckets hash partitioned by ID field and then 4 range partitioned tablets for each hash bucket. When writing data to Kudu, a given insert will first be hash partitioned by the ID field and then range partitioned by the packet_timestamp field. The result is that writes will spread out to four tablets (servers). Meanwhile read operations, if bounded to a single day will query only the tablets containing data for the given day This is important, without much effort, we are able to scale out writes and also bound the amount of data read on timeseries reads.

Step-3: Test the entire topology “UDP-KafkaProducer-KafkaConsumer-ApacheKudu”

  1. Ensure both the traffic simulator and UDP_Kafka_Producer are running
  2. On “Kafka Consumer to Apache Kudu” StreamSets Pipeline, click on the “start” button
  3. You should see some statistics as seen in the image below

StreamSets Data Collector Stats


In the Impala shell, query the netflow table to see the data in Kudu:

Impala shell: Kudu Results


Impala-Kudu to D3 Visualization

This is a small custom visualization which shows the source IP and destination IP along with the time interval. The visualization is colored based on the number packets the source system sent to the destination system.

  1. Download code base from here
  2. D3 is a JavaScript visualization library. In order to start the web-server that will serve the relevant JavaScript code, you can execute the following commands in your terminal. Note that you will need Maven to be installed on your machine
  3. $ git clone
  4. $ cd code/app-dataviz-from-impala
    $ mvn spring-boot:run

Upon starting the server, navigate to http://localhost:1990/timetravel.html on your favorite browser, and admire the beauty of these real-time netflow IP communication visualizations.



StreamSets Data Collector allows you to easily move NetFlow data from UDP to Apache Kafka to Apache Kudu for analysis. Kafka provides an intermediate message buffer, while Kudu provides both real-time inserts and fast analytics. Download SDC today and build your first pipeline!

Sandish Kumar is a Solutions Engineer at phData who builds and manages solutions for phData customers. Sandish spends his spare time working to understand Kudu internals.