Continuous Delivery and Micro Services - A Symbiosis

Continuous Delivery & Micro Services

A SymbiosisEberhard Wolff

Freelancer Head Technology Advisory

Board adesso AG http://ewolff.com

Eberhard Wolff - @ewolff

Leseprobe: http://bit.ly/CD-Buch


Micro Service




How can I implement a

new feature???

Eberhard Wolff - @ewolff L


ECommerce System

Spring & OSGi

New Stuff


New Stuff Spring & OSGi

New Stuff

ECommerce System


HTTP

New Stuff

Links

No legacy code Any technology

J Small code base

Little programs are delightful to write in

isolation,but the process of

maintaining large-scale software is always

miserable.

Jaron Lanier

Friedenspreis des

deutschen Buchhandels


Micro Services: Definition•  Small •  Independent deployment units •  i.e. processes

•  Any technology •  Any infrastructure

Micro Service

Server

Micro Service

Server


Components Collaborate

Micro Service

Micro Service

Link

Data Replication

REST Messaging


Why Micro Services?•  Strong modularization •  i.e. no unwanted dependencies

•  Choose best technology for each service •  Includes database etc

•  Teams can deploy new features •  Completely independent •  Micro Service must provide meaningful

set of features


Continuous Delivery


Continuous Delivery: Build Pipeline

Commit Stage

Automated Acceptance

Testing

Automated Capacity Testing

Manual Explorative

Testing

Release


Continuous Delivery•  Automated provisioning

•  Fast Feedback •  Tests, tests, tests… •  Feedback from production •  Monitoring •  Logs analysis


Why Continuous Delivery?•  Faster time to market •  i.e. can deploy changes quickly into

production

•  Less risk •  Many tests •  Automation mean reproducible results •  Smaller deployments


Why Continuous Delivery Needs Micro Services


Monolith

ECommerce System

3rd party systems

Database


Continuous Delivery: Build Pipeline

Commit Stage


Testing

Automated Capacity Testing

Manual Explorative

Testing

Release

ECommerce System


Build Pipeline: Problems•  Complex infrastructure •  Huge database •  3rd party integration

•  Slow feedback •  Test everything for each commit •  Huge deployment unit •  Deployment slow


Micro Services•  Small independent deployment units •  E.g. interface backwards compatibility •  Otherwise Micro Services would need

to be deployed together

•  Sensible set of features •  Business features should be deployed

independently


Micro Services

ECommerce System

3rd party systems

Database

Order

Customer

Item


Commit Stage


Testing Automated

Capacity Testing

Manual Explorative

Testing

Release

Commit Stage


Testing Automated

Capacity Testing

Manual Explorative

Testing

Release

Commit Stage


Testing Automated

Capacity Testing

Manual Explorative

Testing

Release Order

Item

Customer


Build Pipeline for Micro Services

•  Independent deployment •  Build pipeline per Micro Service

•  Smaller •  Easier to set up •  Less features (3rd party systems) •  Faster Feedback: Less tests


Micro Services

ECommerce System

3rd party systems

Database

Order

Customer

Item


Micro Service & Databases•  Micro Services don’t share data •  i.e. database (schema) per server

•  Easier schema migration •  Easier deployment


Micro Services Design•  System becomes a distributed system

•  The network is not reliable •  Micro Services fail

•  A failed Micro Services must not cause other to fail


Resilience


Resilience

A system built out of unreliable

components with resilience is more robust.


Would you reboot your database just

like that?


Amazon Reboot•  Amazon Cloud rebooted several

machines •  Netflix: video streaming •  Peak: 30% of internet traffic in the US •  2700 database server •  218 rebooted •  22 not successful •  0 downtime


Risk Mitigation in Continuous Delivery

•  Blue / Green Deployment •  Create complete cluster with new

release •  Test and only switch if OK

•  Canary Releasing •  Release to a few nodes •  Rollback if needed


Micro Services: Further Risk Mitigation

•  Smaller deployment units •  Deployment Failure influences less

features •  Easier rollback / fixing

•  Resilience: Other Micro Services still operational


Why Micro Services Need

Continuous Delivery


Micro Service & Servers•  Potentially different technology

stack per service •  Individual processes

•  Each component has its own server •  …per stage in the pipeline


Not one server


Not 10 server


But a lot more


Micro Service: Not just a piece of

software


Micro ServiceApp +

App Server + Database +

More infrastructure

Individual technology stack


Micro Services & Automation•  Infrastructure much more complex •  More servers •  More services

•  Need to automate provisioning •  (Virtual) Servers •  Software •  Complete software stacks


Micro Services & Feedback: Logs

•  Simple grep on a log file not enough •  Too many servers •  Correlation across servers

•  Centralized logging needed


Micro Services & Feedback: Monitoring

•  Just top on a server is not enough •  Too many servers •  Not just your application… •  …also database •  …other infrastructure

•  Centralized monitoring needed


Why??


Quick Deployment

Continuous Delivery

Delivery Pipeline

Micro Services Smaller

Deployment Units

Independent Deployment

Units


Quick Deployment

Tests

Continuous Delivery

Monitoring

Logs Fast

Feedback


Conclusion


Micro Services & Continuous

Delivery: Goal is quick deployment.


Time to Market


Conclusion: Quick Deployments

Time

Size & Risk

Manual Deployment

Pipeline

Continuous Delivery Pipeline

Monolith Micro Services


Conclusion

Micro Services

Continuous Delivery

Infrastructure much more complex

Smaller deployment units


Micro Services and Continuous Delivery go together.


You must do both: Continuous Delivery &

Micro Services


You must do both: Continuous Delivery &

Micro Services


Migration to Continuous

Delivery or Micro Services much

harder


Migration to Continuous

Delivery or Micro Services much

harder


Continuous Delivery for a

Monolith might be unrealistic


Alternative Approach

ECommerce System

Database

Micro Service

Database

Integration


Migration to Micro Service and Continuous Delivery

•  Micro Services can be added to a Monolith

•  Might use different technologies •  Different way to handle legacy

applications •  Easier to create a Continuous

Delivery Pipeline for Micro Service •  But: Higher overall complexity


Thank You!