Integration via #BPM: become friendly to #cloud

Integration via #BPM:become friendly to #cloud

A. Samarin

BPM for integration, v2 2

1. #bpm for developers: improve #agility of implementations http://improving-bpm-systems.blogspot.com/2013/04/bpm-for-developers-improve-agility-of.html

2. Addressing #security concerns through #BPM at http://improving-bpm-systems.blogspot.com/2013/04/addressing-security-concerns-through-bpm.html

© A. Samarin 2013

Related articles

http://improving-bpm-systems.blogspot.com/2013/04/bpm-for-developers-improve-agility-of.html







http://improving-bpm-systems.blogspot.com/2013/04/addressing-security-concerns-through-bpm.html





• Technologist-driven

• Weak connection to the business tempo (famous night batches)

• Not easy to trace, audit, maintain and evolve

© A. Samarin 2013

Integration practices without SOA

Monolithic application 1

Presentation layer

Business logic layer

Persistence layer

Monolithic application 2

Presentation layer

Business logic layer

Persistence layer

Client-base integration

Functional API integration

Data-centric integration

BPM for integration, v2 4© A. Samarin 2013

From monolithic applications to universally interconnected and interdependent services

Monolithic application

GUI screen 2GUI screen 1 GUI screen 3

Business logic

BO1 persistence BO2 persistence

Business logic service

Interactive service 1



Enterprise Service Bus (ESB)

BO1persistence service

BO2persistence service

SOA solution


• As all applications are constructed in SOA way (services and ESB) then the integration looks like plugging mobile phones to the telephone network

© A. Samarin 2013

ESB-centric integration between services

Service

A1

Former monolithic application AService

A2

Service

A3

Service

A4

Service

A5

ESB

Service

B1

Former monolithic application BService

B2

Service

B3

Service

B4

Service

B5


• Only the flow of data is traceable

• Flow of control is not explicit, althoughthe primary importance is the result of working together, but not individual exchanges (like in the football)

© A. Samarin 2013

Problems with ESB-centric integration (1)


• N-to-N connectivity which has the N*(N-1)/2 complexity

• Where to keep the state for a composite service?

– If in ESB then this makes ESB too complicated

• Is ESB cloud-friendly?

– imaging a re-start of the VM with the ESB

– ZapThink http://www.zapthink.com/2013/05/21/cloud-friendly-bpm-the-power-of-hypermedia-oriented-architecture/

• Only ESB is not enough; what to add?

© A. Samarin 2013

Problems with ESB-centric integration (2)

http://www.zapthink.com/2013/05/21/cloud-friendly-bpm-the-power-of-hypermedia-oriented-architecture/

http://www.zapthink.com/2013/05/21/cloud-friendly-bpm-the-power-of-hypermedia-oriented-architecture/

BPM for integration, v2

• BPM, by revealing the artefacts and the relationships between them, provides the necessary context (e.g. granularity) for the definition of services

• SOA provides recommendationsfor the implementation, execution and governance of services

• Recursive relationship

– All processes are services

– Some operations of a service can be implemented as a process

– A process includes services in its implementation

© A. Samarin 2013 8

Using BPM for constructing composite services


• Application services are connected (via ESB) only to the coordination service thus removing N-to-N connectivity

© A. Samarin 2013

Making coordination explicit and arranging services around it

Application services

Coordination service

Resource services

Aggregation services


• Each resource has its own life-cycle

• Many variants of duration process instance vs. resource life-cycle

• REST helps to check the state of a resource

• REST helps to implement idempotency

© A. Samarin 2013

Using REST to access resources

Time

Resource 3Resource 2Resource 1

Resource 4

Process instance 1


• To decouple processes

• See also EPN and BPMN Explicit event processing agents in BPMN? at http://improving-bpm-systems.blogspot.com/2011/01/explicit-event-processing-agents-in.html

• EPN, CEP, BEM are important

© A. Samarin 2013

Using events (1)

http://improving-bpm-systems.blogspot.com/2011/01/explicit-event-processing-agents-in.html







• To externalise the flow of control from existing monolith applications

© A. Samarin 2013

Using events (2)


• WHY?

– Use of distributed architecture for scalability and fault-tolerance

– Use of clouds (where any service may be disconnected or failed & VM reloaded)

• HOW?

– See also “BPM for developers: improve agility of implementation”

– Error recovery loop for the invocation of each service with automation

– Idempotency in the design of services and processes

© A. Samarin 2013

Easy recovering from errors by design


• Imagine a process fragment with 3 automation activities (A, B, and C) to be executed as a transaction; each of those activities is an invocation of an external services (not in the run-time as the coordination service); normal execution sequence is E2-A-B-C-E4

• Because those services may fail this fragment contains intermediate exception event E3 and an activity for Error Recovery Procedure (ERP); the latter may be a human activity

© A. Samarin 2013

Idempotency explained (1)


• First pass with the failure of activity B

– E2-A(done)-B(failed)-E3-ERP

• Second pass with failure of activity C

– E2-A(already done)-B(done)-C(failed)-E3-ERP

© A. Samarin 2013


❻

❶ ❷

❺

❸

❹

❶ ❷

❺

❸ ❹


• Third pass with no failures

– E2-A(already done)-B(already done)-C(done)-E4

• Activity A was executed 3 times, but it did the real work only at the first time – two other times were ignored because of idempotency

• Example of idempotent service: upload a document; if document’s place, metadata and content are the same then next upload is ignored

© A. Samarin 2013


❶ ❷ ❺❸ ❹


• Any service can be in a cloud

• See also Enterprise pattern: #Cloud-Ready Estimation and Evaluation Procedure (CREEP) at http://improving-bpm-systems.blogspot.com/2011/12/enterprise-pattern-cloud-ready.html

• Any service may fail; connectivity to a cloud may fail

• If an application service has failed then the coordination service will recover via error recovery loop

• One type of failure is a timeout (because each activity has its SLA)

© A. Samarin 2013

Become friendly to cloud (1)

http://improving-bpm-systems.blogspot.com/2011/12/enterprise-pattern-cloud-ready.html







• If the coordination service has failed then some of running application services cannot complete their associated activities; after the restart of the coordination service, those activities will fail by timeout

• REST should be used to access resources; if a resource may change its state without the control of the process then the process must interrogate the state of such a resource before its usage

© A. Samarin 2013

Become friendly to cloud (2)


• SOA, ESB, BPM, REST, and EPN/CEP/BEM must be used together to achieve the cloud-friendly integration

• Composite services are made by the explicit coordination between other services (i.e. by processes)

• Majority of services are stateless except process-as-a-service and resource-as-a-service

• Recover from errors must be architected

© A. Samarin 2013

Conclusion


Thanks


BACKUP slides


ESB-centric view – only flow of data

ESB

Service 1

Service 3

Service 2


Process-centric view – bothflow of control and flow of data

Process

Service 1

Service 3

Service 2

Primary importance – the result of working together, but not individual exchanges (like in the football)

Integration via #BPM: become friendly to #cloud

Technology

Transcript of Integration via #BPM: become friendly to #cloud