Friedbert Samland, Project Manager IT Application Deutsche Telekom IT and Willm Tüting, Managing Director conology GmbH, describe the transformation of a monolith application to a Microservice-based Camunda inherited architecture. Coming from a technical point of view, with BPEL we had to abstract to a business-oriented process flow using BPMN. Just changing a few letters? Far from it! Setting the scene of the challenges of Telekom IT as a large IT company changing from an organizational implemented waterfall development process, into a software development company facilitating agile principles. Striving the raising complexity due to an agile transformation as well as the utilization of the Cloud and DevOps. We will highlight the Pros and Cons and how to tackle the challenges of a big transformation initiative within the current teams. We will take a journey through several viewpoints where we show you challenges and advantages we met on our way so far.

1. CAMUNDACON 2019
DEUTSCH TELEKOM IT GMBH
LIVE IS FOR SHARING
© Deutsche Telekom IT GmbH– 2019 July

2. In this presentation, we will beyour presenter to show youhow we split up
our monolith into small pieces of microservices
FRIEDBERT SAMLAND (PROJECTMANAGER TELEKOM IT)
WILLM TÜTING (MANAGING DIRECTOR CONOLOGY GMBH)
HELLO & WELCOME!

3. PRESENTATION
AGENDA
Companyprofile:
TelekomIT GmbH
ShortHistory
How CamundaFits intoMicroservices
From MonotlithtoMicroservice
Whatwebuild
01
02
04
05
03

4. CAMUNDACON 2019 4DEUTSCHE TELEKOM IT GMBH
WHO WE
ARE
AND
WHAT WE DO
We areresponsibleforthe design,development
andoperationof allits own andtransferredIT
systemsto supportbusinessprocessesat
DeutscheTelekomAG (in particularTelekom
Deutschland,T-SystemsandGHS)
Thepeopleat TelekomIT dealwith hundredsof
technologies,vendorsand serviceproviders
WHAT WE DO
TelekomIT GmbH isthe internalIT serviceprovider
of DeutscheTelekom AG.
DeutscheTelekomIT hasaround9,700employees
where6,500 are locatedin Germanyand
approximately3,200 employeesareworking at T-
Mobileand T-Systemsin EuropeandBrazil.
Our totalbudgetisaround€ 1.9 billion.
WHO WE ARE

5. CAMUNDACON 2019 5DEUTSCHE TELEKOM IT GMBH
WHAT WE OFFER AT TELEKOM IT
TelekomIToffersa largevariety of solutionsforourcustomersinsidethe DeutscheTelekomAG
E2E responsibilityforRetailandWholesalecustomersofTelekomDeutschland.Costumer
Solution’smainpartsare CRM, CustomerServiceandTechnicalServiceforFixed-Net,
Mobileand IPproducts.
CUSTOMER SOLUTIONS
E2E responsibilityforITsystemsin theTechnicalServiceof TelekomDeutschland.This
incorporatesITsolutionsforplanning,buildingandoperatingtelecommunication
networks.
TECHNICAL SOLUTION
ImplementsandoperatesITsolutionsforthe businessconsumersdepartmentof Telekom
Deutschland.Productslike PBX in thecloud aretheir business
BUSINESS SOLUTIONS
Responsibilityforplanningthe completeIT roadmapandoperationprocessesinTelekom
IT.
DIGITAL TRANSFORMATION AND OPERATION

6. CAMUNDACON 2019 6DEUTSCHE TELEKOM IT GMBH
WHAT WE DO AT CUSTOMER SOLUTIONS?
CustomerSolutionsisresponsibleforall productsandserviceswhich interactwith thedifferenttypesof customers
TheMagentaServiceApp isone of ourfavoriteproducts.
APP PROGRAMMING
Developingsoftwareforbuildingandbilling individualcarrier fixed line
connections.
WHOLESALE INDIVIDUAL MARKET
Developingandmaintainingsystemsto helpourcustomerswith their
problemsandwishes.Self-servicein caseof troublewith their fixed lineor
assistancetodiagnoseerrorswith thetelephoneline.
SERVICE AND ASSURANCE
Developingandoperatingthe WITAplatform for telecommunicationcarriers
in Germany.
WHOLESALE MASSMARKET
Managementof approx.20 millionof direct customerswith fixed lineor
mobileproducts.
CRM-SYSTEM FOR RETAIL CUSTOMERS

7. CAMUNDACON 2019 7DEUTSCHE TELEKOM IT GMBH
A WHOLESALE USECASE FROM FULFILLMENT
ProviderchangeTelekomto 1&1 inshort
STEP 01
End-customerwantsto changeits fixed
line fromTelekom to 1&1
STEP 02
Newcarrier1&1gets theorder from
end-customer
STEP 04
WITA terminatescontractwith
Telekom andorders theline for 1&1
STEP 03
WITA getstheorder forprovider
changefrom 1&1 STEP 06
End-customer hasnewfixed line
connection at1&1
STEP 05
1&1gets thefulfillment messagefrom
Telekom andinformsits new end-
customer

8. “DOIT
FASTMEANS,
DO IT
AUTOMATICALLY”
OUR PROCESSING
Thedifferentwholesaleusecasesare processedin a standardizedway.
Get wholesaleordersin a digital wayto processthem
immediately.
ON TIME
Takecare of the orderin everysituationspeciallyin
exceptionalsituations
RESPONSIBILITY
Runordersfullyautomatedat nearly95%
(actual85%)
EFFICIENCY

9. CAMUNDACON 2019 9DEUTSCHE TELEKOM IT GMBH
A SHORT TIMELINE OF WHOLESALE BUSINESS
Wholesalebusinessfrom2007until today
20082007 20182017
Start processingTAL
orders with Vodafone
and1&1
PRODUCTION
Developmentof a
processorientedand
automatedway for
processingwholesale
orders
DEVELOPMENT
Inflexibilityin developmentand
deploymentdecreased
by firstagileattempts
CHANGE OUR WAY
Telekomstartedthe GIGABIT
initiativeby buildinga new
businesssolutionforordering
FTTXlines
MSA STARTED

10. CAMUNDACON 2019 10DEUTSCHE TELEKOM IT GMBH
THE AS-IS – UP TO THE MARKET? FAR FROM IT!
Themajorobstacleswefacedin2017
Timeto Market
12+month
Large Releases
1000+PT
Media gaps
Alot ofmanualtasks
Outdated
technology
10+yearsold
VendorLock
High costs
Hardware
dependnt
Limited &slow
Waterfall
3+monthperphase
Regression
runtime
2+days
Inflexible
5+dayssetuptime
Compliance
Decreased quality

11. CAMUNDACON 2019 11DEUTSCHE TELEKOM IT GMBH
THE FIRST STEP – DID IT HELP? SADLY NOT!
Waterfalltoagile...
Requirement
3 month
allworkstartsatonce
3 month 3 month
Development
allworkend atthesametime

12. CAMUNDACON 2019 12DEUTSCHE TELEKOM IT GMBH
THE FIRST STEP – DID IT HELP? SADLY NOT!
...is notenoughif youdon‘tadaptit end-2-end!
HeterogenousITheterogenousIT &processes
Largerequirementsstill
Largerequirementsstill
3 month3 month 3 month
Development
Lesson
01 Helpsto overcome longcycle-timesforsmall
requirements&bugfixes
Partially agile is nonsense
Requirement

13. CAMUNDACON 2019 13DEUTSCHE TELEKOM IT GMBH
THE TO-BE – JUST BUZZWORDS? FAR FROM IT!
Fourmajordriverswe identified... but we were lackingthe powerto changethem
01 02
03 04
CLOUD
Thepower of theclouddramatically
reducesruntimesandenablesastaged
fine-gaineddeliveryapproach.
DEVOPS
Automation& Self-Serviceaspartsof
ourDevOpsphilosophyarethe keysto
quality& speed.
SAFE
Introducinga new organizationwith
shortercycle-timesend-to-endenables
flexibilityandspeed.
MICROSERVICES
An approachto partitionthe monolithand
enablecross-functionalwork.

14. CAMUNDACON 2019 14DEUTSCHE TELEKOM IT GMBH
THE TRANSITION - LUCKY US
Light at theendof thetunnel:A newproductaroseonthe horizon...
OUR SUCCESS FORMULA
"TheForce" waswith us!
THE RIGHT REQUIREMENT
Thenew product'FTTH' shouldchangethe
wholecompany
THE RIGHT DIMENSIONS
All dimensionscouldbechanged:
Specification,implementation,testing,etc.
THE RIGHT STAKEHOLDERS
Stakeholderswere onoursideand approvedour
new approachbasedona new architecture

15. CAMUNDACON 2019 15DEUTSCHE TELEKOM IT GMBH
SAFE
Agile @ scale
Lesson
02 Agile isn’tbottom-upnortop-down,successneeds
both!
From 0 to agile E2Eis nonsense

16. CAMUNDACON 2019 16DEUTSCHE TELEKOM IT GMBH
CLOUD - NO READY MADE SOLUTIONS
Cloudisn't easy,it's a newparadigm, it addscomplexity, butit ...
FACILITATES STAGING
New stagesarejusta matter of need& costs,
but notset-uptime
SCALES WITH THE NEEDS
If youneedmore “hardware”youjust
provisionit!
REDUCES DEPENDENCIES
Youdon’tneedto care thatmuch about
maintenancein developmentanymore.
ALLOWS CONSTANT UPDATES
Youcan constantlystayup-to-datewith your
frameworks
BRINGS ALONG A LOT OF BENEFITS
Reducedf.e. thestandardmaintenancetaskat a significant
level.
ENABLES SELF-SERVICE
Developerscanperformall theirtasks
independentof a centralizedfunction
Lesson
03 Benefits take time and the way
bears a lot of pitfalls
Cloud has a high learning curve

17. CAMUNDACON 2019 17DEUTSCHE TELEKOM IT GMBH
DEVOPS - EMBEDDED ENABLER?
Startingwith DevOps is a hugemindchange forDev & Ops people
FRAMEWORK
MANAGEMENT
INFRASTRUCTURE AS
CODE
CONTINUOUS
EVOLUTION
COMPLEX
TOOL STACK
HIGH DEGREE OF
AUTOMATION
HANDS OFF!
AVOID ‘LATEST’ CHANGE AS
DEFAULT
AVOID TO DO ALL-
AT-ONCE
THINK BIG,
START SMALL
Lesson
04 Don’t lose track. Keep focused on
benefits instead of beauty.
DevOps is a huge topic

18. CAMUNDACON 2019 18DEUTSCHE TELEKOM IT GMBH
MICROSERVICES – PROMISES AND CHALLENGES
Thehopeswere high, theriskstoo?
PROMISE 03
typicalinterfacechangesof
partnersystemsshould
onlyaffectfew
microservicesPROMISE 02
with increasingloadit
shouldbe possibleto only
scaleup
PROMISE 01
typicalbusiness
requirementsshouldonly
affectfew microservices
CHALLENGE 05
complexcentral
mechanismsshouldbe
developedonce and
resused
CHALLENGE 04
the numberof
microservicesshouldbe
neithertoo high nor too
low
BASIC FACTS
Next to promisesand challengeswe hadsomebasicfacts
thatmade uscautious.
1.5 MILLION
Lines of Code
400+ WEBSERVICES
Components
80+ OPERATIONS USED
Interfaces

19. “FIRSTPRODUCTIVE,
VERSION
AFTER8 MONTHS”
OUR NEW DEVELOPMENT
We identifiedthreemajorchanges.
Changedevelopmentfrom BPEL to Java andmodusoperandi
from waterfallto agile
SPEED UP
Changefrom skill-basedtailoredteamsto international
cross-functionalteams
CROSS-FUNCTIONAL TEAMS
Increasedevelopmentefficiencyby using Camunda,
SPRINGand otherstate-oftheart technologies.
EFFICIENCY

20. CAMUNDACON 2019 20DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: ARCHITECTURE OF THE MONOLITH
Frommonolithtomicroservicearchitecture
As-Is-Architecture
BPM-Engine (Oracle SOA Suite /
BPEL)
Fulfillment
(„KP9“)
SOAServices+Interfaces
Assurance
(„KP10“)
Preponed
PreOrder
(„PPO“)
Order State
Manageme
nt
(„ASV“)
tight coupling
Microservice PreOrder
Microservice PreOrder
Microservice Order
Microservice Order
Microservice Assurance
Microservice Assurance
Microservice Business
Control
Microservice Business
Control
Target Architecture
REST
API
MessageBroker
…
REST
API
REST
API
REST
API
REST
API
REST
API
REST
API
REST
API
…
…
…
loose coupling
Where is Camunda?
Stay tuned!

21. CAMUNDACON 2019 21DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: PARTITIONING OF THE MONOLITH
Our 5-Stepapproach
DATA
01

22. CAMUNDACON 2019 22DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: PARTITIONING OF THE MONOLITH
Step1: Categorizedata
22
Order
D1:Datareceived fromfrontends
Comments
Notifications
ContactPersons
Dates
D3:Dataexchangedwithbackends
...
Addresses
Contracts
Assets
...
Reposonsesof Fullfillment
Telephonenumber
...
ReservationResults
...
Customerdata
Notifications
Backend System A
Backend System B
Backend System c
...
Backend System D
Backend System D
...
...
Backend System F,G
Backend System F,H
...
Backend System E
... ...
--- ...
D0:Businessconfiguration
Errormatrix
...
Calendar
Systemdatatables
D2:Datagenerated/calculatedbythesystem
Timestamp
Ordercount
state/Statehistory
...
Errors
connectedOrders
...
Products
System messages
Manualsteps
Orderpositions

23. CAMUNDACON 2019 23DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: PARTITIONING OF THE MONOLITH
Our 5-Stepapproach
DATA
01
02
FUNCTIONALITY

24. CAMUNDACON 2019 24DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: PARTITIONING OF THE MONOLITH
Step2: Categorizefunctionality
24
F2) End-to-endbusinessprocesses
 Fulfilmentprocesses,e.g. provision,servicechange,providerchangeetc.
 runtimevariesstrongly between„very short/online“(afewsecondse.g.
inquiries)forsynchronousprocessesand„verylong“(upto2years,e.g.
orders)forasynchronousprocesses
F4) Domainspecificprocesses
 Reusableprocesssegmentsthatarecalledbytheend-to-endbusiness
processes
 createrequeststobackendsystems
 evaluateresponsesfrombackendsystems
 runtimeis normallyshortto medium(afewhours),butcanalsobehigher
forprocesssegmentsthatwaitforresponsesfrombackendsystems
F3) Provideand/ orcalculatedata
 Calculation-andcountingfunctions(e.g. calculationofdatesand
countersforplanningagreements)
 Informationfunctions(e.g. „readorder“and„searchorder“)
 Configurebusinessparameters(e.g. errorassessmentmatrix,notification
codetable,calendar)
 runtimeis normally“veryshort / online“(afewseconds)
F1) Complexcentralmechanisms
 Selectionofthecorrectend-to-endprocessforanincomingorder
(„processframeworkfunctionality“)
 Coordinationofmultipleorders(e.g. “orderbracket”,cancellation,
rescheduling,waitingfor openorders)
 Coordinationofdifferentbusinessclusters
 ExceptionHandling+Portal-Stop
 Timeout-Monitoring

25. CAMUNDACON 2019 25DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: PARTITIONING OF THE MONOLITH
Our 5-Stepapproach
DATA
01
02
03
CATEGORIES
FUNCTIONALITY

26. CAMUNDACON 2019 26DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: PARTITIONING OF THE MONOLITH
Step3: Defineandassignmicroservicecategories
26
Category A: Business Process Microservices
Microservicesinthiscategory
 containthelogictocontrolcomplex central
mechanisms(functionallevel F1)
 realiseshortorlongrunningend-to-endprocesses
(functional levelF2)
 donotmanage(persistent)data,
 choose thecorrectend-to-endprocessforan
incomingorder
 delegateworktoprocesssegments( Domain
microservices)
 informabouttheprocessstatusandthestatushistory
Category B: DataMicroservices
Microservicesinthiscategory
 managethebusinessconfiguration
(datacategoryD0)
 managedatareceivedfromfrontends
(datacategoryD1)
 managedata,thathasbeencreatedand/orcalculated
byothers(datacategoryD2)
 expose informationandcalculationfunctionsfor
thesedatacategories(functionallevelF3)
 implementa datadeletionstrategy(deletedataas
soonasitisn’tneededanymore)
Category C:Domain Microservices
Microservicesinthiscategory
 managedataexchangedwithbackends
(datacategoryD3)
 expose informationandcalculationfunctionsfor
thesedatacategories(functionallevelF3)
 implementa datadeletionstrategy(deletedataas
soonasitisn’tneededanymore)
 realiseshortrunningprocesssegments(functional
levelF4)
 thatcreaterequeststobackendsystems
 thatevaluate(intermediaryand final)responses
frombackendsystems

27. CAMUNDACON 2019 27DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: PARTITIONING OF THE MONOLITH
Our 5-Stepapproach
DATA
01
02
03
04
CATEGORIES
COMMUNICATIONFUNCTIONALITY

28. CAMUNDACON 2019 28DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: PARTITIONING OF THE MONOLITH
Step4: Designcommunicationof microservicecategories
Backend(s)
Frontend(s)
Category B
„Data Microservices“
API API
synchronous asynchronous
call businessprocess
callbackend/
publish data
receive
response
calldomainspecific MS
signalsuccessful
completionorerror
startbusiness
process
reador writedata
readdata
reador writedata
readdata
readdata
Category C
„Domain Microservices“
reador writedata
publish data
determineprocess status(+history)
Category A
„BusinessProcess
Microservices“
API
API
API

29. CAMUNDACON 2019 29DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: PARTITIONING OF THE MONOLITH
Our 5-Stepapproach
DATA
01
02
03
04
CATEGORIES MICROSERVICES
COMMUNICATIONFUNCTIONALITY
05

30. CAMUNDACON 2019 30DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: ARCHITECTURE OF THE MONOLITH
Orchestrationvs. Choreographyinspiredby TheMicroservicesWorkflowAutomationCheatSheet from BerndRücker Blog
Choreography
MessageBroker
Microservice 1
Microservice 2
Microservice 3
Microservice n
…
Orchestration
BPM Engine
Micro-
Servic
e1
Micro-
Servic
e2
Micro-
Servic
e3
Micro-
Servic
en
…
Our solution: „choreographed orchestration“
MessageBroker
Micro-
Service 1
Micro-
Service 2
Micro-
Service 3
BPM Engine
BPM Engine
BPM Engine
Micro-
Service n
…
BPM engine is a central
manager
 monolithic!
microservices
are loosely
coupled, but
where are the
processes?
orchestratio
n
choreograph
y
not every
microservice needs
a BPM engine
central process
monitoring and
management

31. CAMUNDACON 2019 31DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: PARTITIONING OF THE MONOLITH
Step4: Designcommunicationof microservicecategories
Category A
„BusinessProcess
Microservices“
Backend(s)
Frontend(s)
Category B
„Data Microservices“
DataAPI
Process
API
DataAPI
synchronous asynchronous
callbusiness process
callbackend/
publish data
receive
response
startdomain specificprocess
Process API
signalsuccessful
completionor error
reador writedata
readdata
reador writedata
readdata
readdata
Category C
„Domain Microservices“
Camunda
Camunda
reador writedata
publish data
startbusiness
process
determineprocess status(+history)

32. CAMUNDACON 2019 32DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: WHAT WE BUILD WITH CAMUNDA
Camundaof coursewas not theonlytool, but...
DEV OPS
Test Monitor
Integrate
DeployPlan
Code
Build Operate
RabbitMQ
Swagger
Spring Cloud Config

33. CAMUNDACON 2019 33DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: WHAT WE BUILD WITH CAMUNDA
One of ourMajorBusinessProcessMS
Domain MS

34. CAMUNDACON 2019 34DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: WHAT WE BUILD WITH CAMUNDA
Communicationpatternbetweenmicroservices:Call a domainmicroservice
Domain MS

35. CAMUNDACON 2019 35DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: WHAT WE BUILD WITH CAMUNDA
Howa domainmicroservicecanwork
Domain MS

36. CAMUNDACON 2019 36DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: WHAT WE BUILD WITH CAMUNDA
Communicatonpatternbetweenmicroservices :Receiving response from thedomainmicroservice
Domain MS

37. CAMUNDACON 2019 37DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: WHAT WE BUILD WITH CAMUNDA
WhereCamundasupportsusstrongly
Domain MS
Noninterrupting
scope
for concurrent flows
Interrupting scopes
for specical
situations
Scoping

38. CAMUNDACON 2019 38DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: WHY CAMUNDA IS A GAMECHANGER
... Camunda wasa majordriver andenablerbecauseof:
Business - IT
Alignment
Development Operations
WHY CamundaMAKES
THE DIFFERENCE
01
02
03
BUSINESS IT ALIGNMENT
• HumanTasks
• Designprocessesastheyrunlateron
• Visualizecomplexlogic
DEVELOPMENT
• Samelanguagewith the business
• Lightweight engine
• Native JAVA support
OPERATIONS
• TheCamunda Cockpit
• TheToken-Concept
• Supportsourcustom ExceptionHandling

39. CAMUNDACON 2019 39DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: TRANSITION OF THE MONOLITH
AuditView
Due to decoupling we decided to use separate DBs for every microservice using Camunda.
The Cockpit isforoperations,butfor 3rdlevel onwardsit requireda differentsolution.
SITUATION: ANALYSIS OF A BUSINESS PROCESS
Caller Sequence: Creates an easy to follow overview of the flow of a
businessprocess.
Logging Insights: Got enriched with all underlying logging data
relevant for 2nd, 3rd, Last-level-Support as well as the development
teams.
Performance Indications: Gives indications about runtime,
bottlenecks,timeoutsandotherperformancerelatesissues.

40. CAMUNDACON 2019 40DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: TRANSITION OF THE MONOLITH
Compliance-by-default
Due to the global distributed teams, multiple vendors and sensitive data, a highly
automated solution was required. The result is an architecture that enables compliance-by-
default.
SITUATION: GLOBALLY DISTRIBUTED TEAMS
Clean Definition: While defining the Specifications the business
analystsenrich theAPIswith complianceattributes.
Automated pseudonymization: When required an automated tool
createspseudonymizedsetsof therequireddata.
Close Collaboration: Due to the short cycle times of providing
consistentdatacollaborationisenhancedsignificantly.

41. CAMUNDACON 2019 41DEUTSCHE TELEKOM IT GMBH
YOUR SPEAKERS
Let‘sconnect!
Willm Tüting
conology GmbH
+49 175 520 96 02
willm.tueting@conology.net
Friedbert Samland
Deutsche Telekom IT GmbH
+49 6151 5819011
friedbert.samland@telekom.de

42. CAMUNDACON 2019 42DEUTSCHE TELEKOM IT GMBH
WHAT'S-NEXT– ARE WE DONE? FAR FROM IT!
Backup

43. CAMUNDACON 2019 43DEUTSCHE TELEKOM IT GMBH
Classic Architecture
Processframe
Businessprocess
Step A
Step D
Call
Call
AMQ
P
REST
Microservice-Architecture (MSA)
Activity
Management Order-
Date
Bestand lesen (BV-W)
ProcessData
Management Proces
s-Data
Bestand lesen (BV-W)
AssetManagement
Asset-
DataStep B Step C
REST
REST
MICROSERVICES: TRANSITION OF THE MONOLITH
TheCloud-Bridge
Forntend(s)
Order
Cloud-Bridge
Step B
Step C
Call
Call
Call
Call
BackendBBackendAD
Call
Call

44. CAMUNDACON 2019 44DEUTSCHE TELEKOM IT GMBH
MICROSERVICES: TRANSITION OF THE MONOLITH
EH Service
ExceptionHandling Scope
Task 1
an erroroccurs
in Task 3Task 2
„Phase 1“
End
EH Scope
Start
EH Scope
ErrorHandler manual
user chooses
a reaction
read reaction
from FBM
read mode
from FBM
automatic
create listof
possible
reactions
jump to
chosen
milestoneStart
mode?
catch error(errorcode)
claimerror
handling task
(polling)
Start
(normal)
End
„Exception
Handler“
(runs
permanently)
create error
handling task
handle “Reject”
Camunda REST API
complete error
handling task
Reject chosen?
no
yes
End
deleteToken (and thus cancel theEHTask)
create Token
1
2
3
4a
start EH
process
4b
5 6
7a
7b
x Other reaction was chosenReject waschosenShared call
8
8
8a
8b
9
10
Task 4 Task 5
„Phase 2“
xx
External Task Client
Reject
11
12
implicit milestone
explicit milestone Implicit milestoneImplicit milestone
Restart„Phase1“ was
chosenas reaction
Fehler-
Bewertungs-
Matrix