At Comcast we are working on the future of television. Change and innovation are happening more rapidly than ever thanks to the cloud based X1 platform which is gradually replacing the legacy set top box installation base. The transition requires us to find innovative solutions to tough design problems around availability and scale. This webinar will present a detailed look at the X1 DVR service as a case study of how CMB and Cassandra can be part of a solution to these problems. A brief high-level overview of the X1 platform will also be provided for context. Join the webinar, and you’ll learn: - High-level overview of the new X1 platform - How Cassandra provides availability and scale for large distributed architectures across data center - X1 DVR as a use case of CMB and Cassandra at Comcast

1. Building Blocks for the Future of Television
DataStax Webinar 5/6/2014
Boris Wolf

2. Driving Innovation at CSV
Evangelize
Infrastructure
Cross Platform
Services
Expand
TV Platform / X1
Extend
Home Platform
Demonstrate
Syndicate
to other platforms
Experiment

3. An entirely new cloud-
based, personalized, and
interactive TV experience.
X1 Platform Overview

4. Delivering an
engaging, interactive, and
immersive sports viewing
experience.
X1 Sports App

5. Some Examples of C* Usage in X1
• DVR (recording history etc.)
• Personalization
• Preferences
• CMB (message bus)

6. CMB – Cloud Message Bus
• CMB = CQS + CNS
• An Open Source General Purpose High Throughput
Distributed Message Bus Infrastructure for the Cloud
• Queuing and Notification Services
• API compatible with AWS SQS/SNS
• Built on C* and Redis

7. MM M
CQS – Queuing Service
M
M

8. T
http://…
http://…
http://…
……
CQS
SQS
CQS
Publish(M)
M
M
M
M
M
M
SubscribersCNS – Notification Service

9. CMB – Cloud Message Bus
• CMB = CQS + CNS
• An Open Source General Purpose High Throughput
Distributed Message Bus Infrastructure for the Cloud
• Queuing and Notification Services
• API compatible with AWS SQS/SNS
• Built on C* and Redis

10. CMB – Tradeoffs
• Guaranteed delivery (even if recipients loose
messages!)
• Best effort ordering
• Duplicates are possible on occasion

12. t=0
Receive()

13. t=0
VTO=30sec
Process()

14. t=5
VTO=25sec
Delete()

15. t=5

17. t=0

18. t=0
VTO=30sec
Process()

19. t=5
VTO=25sec
Process()

20. t=5
VTO=25sec

21. t=25
VTO=5sec

22. t=30

23. t=30
VTO=30sec
Process()

24. t=35
VTO=25sec

25. t=35

26. SQS / SNS API Compatibility
AmazonSQSClient sqs = new AmazonSQSClient(new BasicAWSCredentials("Z2DV…", "bH2U…."));
sqs.setEndpoint("http://localhost:6059");
// create queue
String queueUrl = sqs.createQueue(new CreateQueueRequest("myqueue")).getQueueUrl();
// send message
sqs.sendMessage(new SendMessageRequest(queueUrl, "my message"));
// receive messages
List<Message> messages = sqs.receiveMessage(new ReceiveMessageRequest(queueUrl)).getMessages();
for (Message m : messages) {
System.out.println(m.getBody());
}

27. CMB Web UI

28. • We actually do: As fail-over option, for proto-
typing, …
• CMB as Open Source alternative to avoid
vendor lock-in
Why not just use AWS SQS/SNS?

29. CMB – Cloud Message Bus
• CMB = CQS + CNS
• An Open Source General Purpose High Throughput
Distributed Message Bus Infrastructure for the Cloud
• Queuing and Notification Services
• API compatible with AWS SQS/SNS
• Built on C* and Redis

30. CQS Implementation - C* and Redis
CMB API Nodes
• Embedded Jetty implementing SQS and SNS APIs
Cassandra
• Cross-DC persistence and replication
• Proven horizontal scalability
Redis
• Avoid duplicates
• Help with best effort ordering
• Handle Visibility Timeout (VTO)

31. Case Study X1 DVR
Scheduler WS
Recorder WS X1 STB
XRE
CQSCQS
XRE
Worker Service
X1 STB
X1 STB

32. Deployment details:
• 2 DC Deployment, 8-Node C* Ring in each (local quorum
reads and writes)
• 10 Redis Shards (each DC)
• 12 CMB Nodes (each DC)
Case Study X1 DVR

33. SQS APIs Params
SendMessage() MessageBody=…
ReceiveMessage() MaxNumberOfMessages=10
VisibilityTimeout=4
WaitTimeSeconds=20
DeleteMessage() ReceiptHandle=1383970619866:0:ed006cabb22dcc80e44f1
967ac259f3b_0_65:2902396753389907544:-
7877921303127914669
Case Study X1 DVR

34. Case Study X1 DVR

35. • Follow SQS/SNS APIs as they evolve (Dead Letter
Queue, Mobile Push)
• C* 2.0 features, CQL3, binary protocol drivers
• Make operations / scaling / capacity planning easier
• Offer CMB as a Service
Opportunities for Improvement

36. Thank You!
http://github.com/Comcast/cmb
http://groups.google.com/forum/#!forum/cmb-user-forum
boris_wolf@sv.comcast.com