In this session we will see what are the scalabilities points of a cloud application. In the first part of the session we will look over the services offered by Windows Azure.

1. Scalability in
Cloud Applications
Radu Vunvulea
vunvulear@gmail.com
http://vunvulearadu.blogspot.com

2. Who am I?
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“email” : ”vunvulear@gmail.com”,
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3. Client requests

4. Is Cloud so different?

5. Cloud Services

6. How can we offer value in our solutions?
• Cloud in general offers a lot of services that can make
our life easier
• Cloud can offer more than machines scalability
• Cloud can help us to create application that are scalable
in more than one point

7. How can we offer value in our solutions?
• Cloud in general offers a lot of services that can make
our life easier
• Cloud can offer more than machines scalability
• Cloud can help us to create application that are scalable
in more than one point
• We cannot offer a Cloud solution without knowing the
environment

8. Table Storage Service

9. Table Storage Service
• Stores any kind of serializable data
• You don’t need any kind of complex data structure or
SQL knowledge.
• Is not a relational database
• In the same table you can have more than one entity
type
• Each entity can have maximum 252 properties + 3
default
• The maximum size of total tables cannot accede 100.000
GB (100TB)
• The maximum size of an entity can be 1MB

10. Windows Azure Blob Storage

11. Windows Azure Blob Storage
• Block blobs
• Support multi-upload of blocks in parallel
• When updating a block, the old version is not
override until you commit it
• Can be used for large files
• Page blobs
• Collection of pages of 512b
• Can be accessed by an offset
• Can be used when the content is changing very often
• Maximum size 100TB

12. SQL Database
• Relational database based on SQL Server
• It is almost like SQL Server from on-premises
• BUT:
• We don’t have support for distributed transactions
• Each table have to contain at least one cluster index
• We cannot attach a database
• We don’t have support for jobs
• Maximum size is 150 GB
• Double check the total cost of a having a SQL Database –
there are a lot of times when we can use Table Storage
Service

13. Queue Storage Service

14. Queue Storage Service
• It is very similar with a named queue from Windows
• You can update the message from a queue
• Support batches (maximum 32 messages on each call)
• Operations: peek, insert, delete, get
• Remark: getting a message don’t remove the message
from queue
• With some work you can even iterate in a queue
• 500 - is the maximum number of messages that can be
processed per second
• Message is persisted until someone will consume it

15. Service Bus

16. Service Bus Queue
• Similar to Queue Storage Service
• The order of the message is guaranteed
• Death Letter support
• Automatically counter for “number of retrives”
• Duplicate messaging detection
• Support for transaction, sessions
• Are not as fast as Windows Azure Queues
• The size of a Service Bus Queue is limited to 5 GB
• Support for ACS (Access Control Service)
• Any kind of serializable item can be added to the queue
• We can even add stream to a message queue (array of bytes )

17. Service Bus Topic
• Multi-distribution mechanism for messages
• Using Service Bus Queues we have 1 to 1 communication
• Using Service Bus Topic we have 1 to n communication
• Each “listener” will receive each message from topic
• Sessions, transaction, death letters are supported
• Two ways for “listeners”
• Receive and delete
• Peek and lock
• The message type is the same with Service Bus Queue –
• BrokeredMessage
• Each message can contain 0 to n properties
• We cannot update or add again the same message

18. Service Bus Relay
• Represent a communication bridge between cloud and on-
premises world
• It is used with success when working with hybrid
application
• Expose WCF services from on-premises servers using
cloud
• Only one entry point
• Requests are persisted even if the on-premises server is
down
• We can control who access our services
• The only thing that need to be changed is on the
configuration file of the server and client
• We can only have request of type Fire And Forget

19. Windows Azure Caching

20. Windows Azure Caching
• Nice feature: you pay only the machine computation
• All the content is in the machine memory
• 2 types of caching:
• Dedicated roles
• Co-located roles (shared memory between application and
cache)
• Cache cluster support (only in combination with a storage account)
• Maximum size of a cache is 14 GB (limited by the memory size of
VM role)
• Each item can have an expiration date
• Built in support for storing web session in the cache

21. Caching Service
• Offer build in caching mechanism
• Can be accessed by anybody from anywhere
based on the namespace
• Maximum size is 4 GB
• Is more expensive than Windows Azure Caching
but can be accessed from any location
• This caching mechanism is offered as a service
• It is similar with Caching Server from on-premise
servers

22. Azure Access Control Service (ACS)

23. Azure Access Control Service (ACS)
• Provide us a mechanism to authenticate users from
different identify providers: FB, Google, Y!, Live … even
custom identify providers and Active Directory (2.0+)
• Is based on a claim based authentication
• You never work with user credentials
• Depending on the provider, you can access different
information about user
• You don’t need anymore to implement a user
management mechanism
• BUT, if you need, you will need to define roles and
store user id’s

24. Shared Access Signature

25. Shared Access Signature
• Provide a method to offer access to different resources
from storage account
• You can provide access to resources without requiring a
user to authenticate
• It is a simple way to control and manage who have
access to your storage
• The base of this mechanism is a custom token
• You can add, remove and change a SAS at runtime
• Each policy is defined by a unique id
• The validity of a SAS can be limited (time base)

26. Media Services

27. Media Services
• The based action that can be done is: content streaming
• Ingest – first step when content is uploaded (upload and encryption)
• Encoding – Process the media content (change the encoding,
converting and transform) – we can use only supported formats
• Protect – encryption of live streaming using a built-in mechanism
• Streaming – send content to consumers (even Apple HTTP Live
Streaming is supported)
• Support for CDN (Azure and 3th party CDN’s are supported).
• Supported devices: Android, iOS, ,Mac, Windows Phone, Windows 8,
X-box, embedded devices, dedicated devices

28. Computing Services

29. Windows Azure Websites
• Can be used to develop web-application
• Support different technologies (PHP, node.js, .NET)
• MySQL support 
• Low cost support – shared mode
• Reserved mode – dedicated instance
• Git support and a very fast rollback mechanism
• Web.config – doesn’t need to contain Azure
configuration
• Each site runs in an isolated environment

30. Web Roles
• Used to host application composed from multiple tiers
• Each web-role is scalable independently
• In comparison with Azure Websites, a lot of custom
configuration can be done
• Network isolation
• Support for startup tasks
• For example we can run a bat that make a custom
configuration to our firewall or install specific
applications
• Any kind of framework can be used in this machines

31. Worker role
• Perfect place to run long running task
• Can be used with success with web-roles for tasks that run in
background
• Cannot be used to host a web application
• In the moment when the “WHEN(TRUE)” ends the worker role
process stop
• Can be seen as a process that can execute a specific type for an
infinite period of time

32. Virtual Machine
• Can be used to install any kind of operating system from Windows
to Linux
• Built-in support and images available for different versions of Linux
 and Windows.
• Custom machines can be created with our own VHD
• Built-in support for MongoDB, MySQL, Cassandra
• Migration from on-premises to cloud and cloud to on-premises can
be done using VHD

33. Windows Azure Mobile Services

34. Messaging mechanism

35. Messaging mechanism
• Windows Azure Queues
• Windows Azure Service Bus Queues
• Windows Azure Service Bus Topics

36. More messages – What should we do?
• Cloud has is own limits
• Cloud services are like other services

37. More messages – What should we do?
• Split the messages to more than one messaging service
• Based on the type
• Based on the source
• Based on an attribute

38. Caching solutions

39. Caching solutions
• Windows Azure AppFabric Cache
• Cache is seen as a service
• For consumer, the location of the cache is not
relevant
• Windows Azure Cache
• The cache is unique per instance
• Cannot be synchronized between machines in real
time
• Local cache
• In-memory cache

40. Storing binary data

41. Storing binary data

42. Storing binary data

43. Storing binary data
• Images, ISO and binary content
• Can be stored with success on blobs
• CDNs
• Direct access to data (security SAS)
• Videos
• Blobs
• Windows Azure Media Services

44. Storing information
• For cases where we need to write logs or audit data we
can use with success:
• Windows Azure Table + SAS
• Storing any kind of data in a non relational database
• Windows Azure Table + SAS
• Storing relational data
• SQL Azure

45. WCF Services
• Can we expose WCF Services from a private network (on-
premises) into a safe way?
• Can we guaranty that no request will be lost?
• Can we expose services in a manner to be 99% up even if
our servers are up only 90% of time?

46. WCF Services
• Can we expose WCF Services from a private network (on-
premises) into a safe way?
• Can we guaranty that no request will be lost?
• Can we expose services in a manner to be 99% up even if
our servers are up only 90% of time?
• Windows Azure Service Bus Relay

47. Long running task
• We have a web application that has long running task
• Each task take more than 5 seconds to execute
• How we can scale?

48. Long running task
• We have a web application that has long running task
• Each task take more than 5 seconds to execute
• How we can scale?
• Long running request can run on a worker role, that can scale
independent
• The result can be send to web-role using queues
• Client can be notified using Web Sockets or SignalR

50. THE END
Radu Vunvulea
vunvulear@gmail.com
http://vunvulearadu.blogspot.com