A Service Discovery Primer / µCon 2016

The monolith applications world got us used to services connected to each other in direct, easy ways. The cloud environments and the modern and current microservices architectures with virtual or containerized setups where the instances can vary in number and location, create an ever-changing context where the communication between services becomes a bit more complicated.

We explore some of the different patterns of Service Discovery in a microservices architecture, and focus on pros and cons, while also mentioning concrete examples of tools and software available.

Transcript

1. @alexramirez #mucon #servicediscovery A SERVICE DISCOVERY PRIMER µCon 2016 / London / @alexramirez
2. @alexramirez #mucon #servicediscovery A SERVICE DISCOVERY PRIMER ABOUT ME • Alex Ramírez • alexramirez.com • Barcelona (born in Mexico City). • Working with ‘online stuff’ since 1994. • µServices (and SOA/EDA) evangelism, coding, designing, training & consulPng. • This is my 2nd µCon.
3. @alexramirez #mucon #servicediscovery A SERVICE DISCOVERY PRIMER TOC • Where are we? • Service Discovery? • Service Discovery paUerns • Service RegistraPon • QuesPons/Comments
4. @alexramirez #mucon #servicediscovery SOME GENERAL CONTEXT
5. @alexramirez #mucon #servicediscovery IT’S A FAST TRAIN!
6. @alexramirez #mucon #servicediscovery SOME GENERAL CONTEXT IT’S A FAST TRAIN
7. @alexramirez #mucon #servicediscovery SOME GENERAL CONTEXT IT’S A FAST TRAIN
8. @alexramirez #mucon #servicediscovery SOME GENERAL CONTEXT IT’S A FAST TRAIN
9. @alexramirez #mucon #servicediscovery SOME GENERAL CONTEXT IT’S A FAST TRAIN
10. @alexramirez #mucon #servicediscovery SOME GENERAL CONTEXT IT’S A FAST TRAIN
11. @alexramirez #mucon #servicediscovery SERVICE …DISCOVERY? 
 WTF? ( WHY THE FUSS?)
12. @alexramirez #mucon #servicediscovery HOW CAN A CLIENT DETERMINE THE INFORMATION (I.E. ADDRESS & PORT) OF A SERVICE IT WANTS TO CONNECT TO? Someone implementing µServices THE PROBLEM TO SOLVE
13. @alexramirez #mucon #servicediscovery SERVICE …DISCOVERY? SERVICE DISCOVERY 101 • Service Discovery: The way for a client to find about the informaPon (i.e. address:port) of a service that it will connect to. • TradiPonal applicaPons (physical hardware) & configuraPon files. • Cloud environments and architectures are different. • Understand the principles. • What happens with a service found on mulPple hosts?
14. @alexramirez #mucon #servicediscovery PREHISTORY C. 2013
15. @alexramirez #mucon #servicediscovery SERVICE …DISCOVERY? TRADITIONAL APPLICATIONS
16. @alexramirez #mucon #servicediscovery SERVICE …DISCOVERY? BALANCED CASES TOO
17. @alexramirez #mucon #servicediscovery HOW CAN A CLIENT DETERMINE THE INFORMATION OF A SERVICE THAT EXISTS IN MULTIPLE HOSTS
 …THAT CHANGE DYNAMICALLY? Someone implementing µServices THE PROBLEM GETS A BIT MORE COMPLICATED
18. @alexramirez #mucon #servicediscovery THE ‘CLOUD’
19. @alexramirez #mucon #servicediscovery THE CLOUD MAKES ALL EASIER: RIGHT? CLOUD ENVIRONMENTS
20. @alexramirez #mucon #servicediscovery THE CLOUD MAKES ALL EASIER: RIGHT? CLOUD ENVIRONMENTS
21. @alexramirez #mucon #servicediscovery THE CLOUD MAKES ALL EASIER: RIGHT? CLOUD ENVIRONMENTS
22. @alexramirez #mucon #servicediscovery THE CLOUD MAKES ALL EASIER. RIGHT? CLOUDY WEATHER • StaPc configuraPon? • Live system. Deploying services. Service instances. • Service network locaPons change o\en: scaling, upgrades, hosts fail/get replaced. • Service interrupPon is not a possibility. • Dynamic service registraPon and discovery.
23. @alexramirez #mucon #servicediscovery CONTAINERS
24. @alexramirez #mucon #servicediscovery CONTAINERS IMPLY EVEN MORE THINGS TO CONSIDER CONTAINERS • MulPple containers in a single host. • Networking with containers means more “fun”. • Several instances in different containers in a same host. • OrchestraPon
25. @alexramirez #mucon #servicediscovery THINGS TO SOLVE
26. @alexramirez #mucon #servicediscovery SERVICE DISCOVERY TWO MAIN THINGS TO SOLVE • Service RegistraTon • Service registering its informaPon in a central registry. • Host & port (somePmes auth credenPals, protocols, version and/or environment info). • Service Discovery • Client applicaPon querying a registry to get info about the services and locaPon.
27. @alexramirez #mucon #servicediscovery SERVICE DISCOVERY SERVICES CONNECT TO SERVICES
28. @alexramirez #mucon #servicediscovery SERVICE DISCOVERY SERVICES CONNECT TO SERVICES
29. @alexramirez #mucon #servicediscovery SERVICE DISCOVERY SERVICES CONNECT TO SERVICES
30. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS
31. @alexramirez #mucon #servicediscovery CLIENT-SIDE SD
32. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS CLIENT-SIDE SD
33. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS CLIENT-SIDE SD
34. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS CLIENT-SIDE SD
35. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS CLIENT-SIDE SD
36. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS CLIENT-SIDE SD
37. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS CLIENT-SIDE SD
38. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS CLIENT-SIDE SD
39. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS CLIENT-SIDE SD
40. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS CLIENT-SIDE SD: EXAMPLE Ribbon Eureka SD, Service Registry Client, Eureka queries
41. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS CLIENT-SIDE SD Eureka Ribbon Eureka Eureka Eureka
42. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS PRO ET CONTRA: CLIENT-SIDE • Few moving parts • Few network hops
43. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS PRO ET CONTRA: CLIENT-SIDE • Client coupled to the Service Registry • Client-side implemented SD logic • Different programming languages/frameworks in the clients. May mean many libraries to code.
44. @alexramirez #mucon #servicediscovery SERVER-SIDE SD
45. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS SERVER-SIDE SD
46. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS SERVER-SIDE SD
47. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS SERVER-SIDE SD
48. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS SERVER-SIDE SD
49. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS SERVER-SIDE SD
50. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS SERVER-SIDE SD
51. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS SERVER-SIDE SD
52. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS SERVER-SIDE SD: EXAMPLES Google Compute Engine Load Balancing Metadata server ElasPc Load Balancer EC2
53. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS SERVER-SIDE SD: EXAMPLES ELB EC2
54. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS PRO ET CONTRA: SERVER-SIDE • Client-code gets simpler with no SD logic. Discovery is abstracted from the client. • More control over traffic, allowing A/B tests or canary releases. • Most cloud environments provide it as part of the plaform.
55. @alexramirez #mucon #servicediscovery DISCOVERY PATTERNS PRO ET CONTRA: SERVER-SIDE • If the router is not part of the platform, we have a new HA component to setup and manage in our infrastructure. • HA: multiple instances, always visible. • More network hops (compared to client-side), i.e. more latency.
56. @alexramirez #mucon #servicediscovery TINY BREAK
57. @alexramirez #mucon #servicediscovery SERVICE
 REGISTRATION
58. @alexramirez #mucon #servicediscovery SERVICE REGISTRY
59. @alexramirez #mucon #servicediscovery SERVICE REGISTRATION SERVICE REGISTRY DB DB/CLUSTER HA UP-TO-DATE CONSISTENT
60. @alexramirez #mucon #servicediscovery SERVICE REGISTRATION SERVICE REGISTRY: EXAMPLES Eureka Service Registry. Client & server. Library. Service RegistraPon implemented via ephemeral nodes under a namespace. Service RegistraPon implemented with k/v and addiPonal libraries
61. @alexramirez #mucon #servicediscovery SERVICE REGISTRATION SERVICE REGISTRY: EXAMPLES Own system, based on DNS and SRV records. K/V mechanism. Full service discovery system in the library. Built on top of etcd. DNS queries to discover available services. SmartStack framework: Nerve (status of machines/services) + Synapse (SD)
62. @alexramirez #mucon #servicediscovery REGISTRATION PATTERNS
63. @alexramirez #mucon #servicediscovery SELF-REGISTRATION
64. @alexramirez #mucon #servicediscovery REGISTRATION PATTERNS SELF-REGISTRATION
65. @alexramirez #mucon #servicediscovery REGISTRATION PATTERNS SELF-REGISTRATION
66. @alexramirez #mucon #servicediscovery REGISTRATION PATTERNS SELF-REGISTRATION
67. @alexramirez #mucon #servicediscovery REGISTRATION PATTERNS SELF-REGISTRATION: EXAMPLES Eureka
68. @alexramirez #mucon #servicediscovery REGISTRATION PATTERNS PRO ET CONTRA: SELF-REGISTRATION • Service instances know their own info, which allows for a complex set of the state model (up/down adds starPng, available, etc.)
69. @alexramirez #mucon #servicediscovery REGISTRATION PATTERNS PRO ET CONTRA: SELF-REGISTRATION • Service coupled to the Service Registry. • Reg logic implemented in every language/framework used. • A running service unable to handle requests lacks self- awareness to unregister itself.
70. @alexramirez #mucon #servicediscovery THIRD-PARTY REGISTRATION
71. @alexramirez #mucon #servicediscovery REGISTRATION PATTERNS THIRD-PARTY REGISTRATION
72. @alexramirez #mucon #servicediscovery REGISTRATION PATTERNS THIRD-PARTY REGISTRATION
73. @alexramirez #mucon #servicediscovery REGISTRATION PATTERNS THIRD-PARTY REGISTRATION
74. @alexramirez #mucon #servicediscovery REGISTRATION PATTERNS THIRD-PARTY REGISTRATION
75. @alexramirez #mucon #servicediscovery REGISTRATION PATTERNS THIRD-PARTY REG: EXAMPLES Prana ElasPc Load Balancer EC2 Registrator
76. @alexramirez #mucon #servicediscovery REGISTRATION PATTERNS PRO ET CONTRA: 3rd.PARTY-REG. • Service code is less complex with no logic of the registraPon. • The registrar can perform health checks to register/ unregister.
77. @alexramirez #mucon #servicediscovery REGISTRATION PATTERNS PRO ET CONTRA: 3rd.PARTY-REG. • The registrar may have limited state knowledge (up/down), with no info on request handling. • If the registrar is not part of the infrastructure, it’s a new component with HA needs to maintain and configure.
78. @alexramirez #mucon #servicediscovery WRAP UP
79. @alexramirez #mucon #servicediscovery CONSIDERATIONS WHEN CHOOSING
80. @alexramirez #mucon #servicediscovery CHOOSING SD/SR SOME CONSIDERATIONS LB Monitoring Availability Dependencies IntegraPon
81. @alexramirez #mucon #servicediscovery SOME CONSIDERATIONS LIBRARIES, RUNTIME
82. @alexramirez #mucon #servicediscovery SOME CONSIDERATIONS RUNTIME ALTERNATIVES
83. @alexramirez #mucon #servicediscovery SOME CONSIDERATIONS CONTAINERS ARE DIFFERENT
84. @alexramirez #mucon #servicediscovery Text Title Text T.HANKS! @alexramirez #mucon #servicediscovery
85. @alexramirez #mucon #servicediscovery QUESTIONS?
 COMMENTS? @alexramirez #mucon #servicediscovery
86. @alexramirez #mucon #servicediscovery Text Title Text T.HANKS! @alexramirez #mucon #servicediscovery
87. @alexramirez #mucon #servicediscovery CREATIVE COMMONS & COPYRIGHT, RESOURCES Credits & acknowledgements • These slides contain some photographs from Flickr with an AUribuPon-NonCommercial 2.0 Generic creaPve commons licence: hUps://www.flickr.com/photos/bogers/397745699, hUps://www.flickr.com/photos/ jeremysorrells/8075811194, hUps://www.flickr.com/photos/jasonpier/11300873596, hUps://www.flickr.com/ photos/53221801@N07/14118483789/, hUps://www.flickr.com/photos/manthatcooks/107121255/, hUps:// www.flickr.com/photos/sarahridgley/2118754450/, hUps://www.flickr.com/photos/arcPcpenguin/7153378221/, hUps://www.flickr.com/photos/r4vi/16040202797, hUps://www.flickr.com/photos/bump/3981175472/, hUps:// www.flickr.com/photos/jamesclay/4177348515/, hUps://www.flickr.com/photos/61921496@N04/15008331908/, hUps://www.flickr.com/photos/25143108@N04/3233875532/, hUps://www.flickr.com/photos/johnpaulgoguen/ 3644147837/ , hUps://www.flickr.com/photos/36666383@N00/5342204450/ • The remaining photographs were obtained via Google Images from pages with no license informaPon. Please contact for their removal in the event of any copyright issue. • Most graphics are self-made, though some are or include free icons designed by Fripik and Madebyoliver from FlaPcon.
88. @alexramirez #mucon #servicediscovery µCon LONDON 2016 Skillscast / VIDEO • This presentaPon will soon be available on the conference website at the following link:
 hUps://skillsmaUer.com/conferences/7412-con-2016-the-microservices- conference#skillscasts