NATS is a mature, high-performance publish/subscribe messaging system that is a hosted project of the Cloud Native Computing Foundation (CNCF). NATS has a goal of connecting services in the simplest, most secure and reliable way possible, and cloud native applications built using NATS inherit much of that simplicity and become easier to operate, benefiting from the performance and resiliency characteristics from the server. Waldemar Quevedo walks you through how to build an application using NATS and how to set up, deploy, and operate a NATS cluster on top of Kubernetes. You’ll learn core NATS features like publish/subscribe, load-balanced queue subscribers, request/response, and handing connection events and examine NATS cluster setup and client application failover, graceful NATS server shutdown and NATS server configuration reload, and graceful client shutdown with NATS Drain mode. You’ll also learn how to secure a NATS cluster with Transport Layer Security (TLS) and secure streams and services with permissions, account isolation and NATS keys (NKEYS) (ed25519 based), and decentralized permissions via JSON Web Tokens (JWTs).

1. Simple, Secure and Reliable:
Building Cloud Native Applications
with NATS

2. ● Waldemar Quevedo / @wallyqs
● Software Engineer at
● NATS core maintainer
● Author of Practical NATS (Apress, 2018)
About me

3. Practical NATS on O’Reilly Safari
https://www.oreilly.com/library/view/practical-nats-from/9781484
235706/

4. Agenda
● Overview of NATS Messaging
● Setting up NATS on a hybrid Kubernetes cluster
● Show of new NATS v2.0 decentralized auth features

5. What is NATS?

6. NATS is a simple,
production proven,
cloud-native
messaging system.

7. CNCF Landscape
Joined CNCF as an
incubation project
in 2018
https://landscape.cncf.io

8. CNCF Landscape
Joined CNCF as an
incubation project
in 2018
https://landscape.cncf.io

9. CNCF Landscape

10. About NATS
● Created by Derek Collison in 2011 for CloudFoundry
● DNA: Simplicity, performance, security, and availability
● TCP/IP based with a very simple plain text protocol
| PUB | SUB | UNSUB | CONNECT | INFO | MSG | -ERR | +OK | PING | PONG |

11. What if all it took to
connect all your
services was a single URL?

12. An always available dial-tone

13. An always available dial-tone

14. An always available dial-tone

15. An always available dial-tone

16. An always available dial-tone

17. An always available dial-tone
❌
❌

18. An always available dial-tone
❌
❌

19. Performance

20. NATS Go client performance

21. Delivery modes

22. Delivery modes
At most once (Core)
● No guarantee of delivery
● Messages can be lost
● Applications must detect and handle lost messages
https://github.com/nats-io/nats-server

23. Delivery modes
At least once (Streaming)
● Ensure message delivery
● Messages are persisted
● Messages may be delivered more than once
https://github.com/nats-io/nats-streaming-server

24. +30 client languages available

25. +30 client languages available

26. Core of NATS:
3 Simple Patterns

27. Messaging Patterns
● Publish/Subscribe (1:N)
● Request/Reply (1:1)
● Load Balanced Queue Subscribers (1:1)

28. Messaging Patterns
● Publish/Subscribe (Streams)
● Request/Reply (Services)
● Load Balanced Queue Subscribers (Streams or Services)

29. Publish/Subscribe (1:N)
NATS
Client
SUB foo
PUB foo
NATS
Client
NATS
Client
NATS
Client

30. Publish/Subscribe (1:N)

31. Request/Response (1:1)
NATS
Client
NATS
Client

32. Request/Response (1:1)

33. Request/Response (1:1)

34. Request/Response (1:1)

35. Request/Response (1:1)
PUB help
NATS
Client
SUB help
NATS
Client
NATS
Client
NATS
Client

36. Request/Response (1:1)
PUB help
NATS
Client
First message would be lowest latency response
NATS
Client
NATS
Client
NATS
Client
SUB help

37. Request/Response (1:N)
PUB help
NATS
Client
NATS
Client
NATS
Client
NATS
Client
Scatter & Gather multiple replies
SUB help

38. Request/Response (1:N)
PUB help
NATS
Client
Scatter & Gather multiple replies
NATS
Client
NATS
Client
NATS
Client
SUB help

39. Request/Response (1:N)

40. Request/Response (1:N)

41. Load Balanced Queues
SUB foo workers
PUB foo
NATS
Client
NATS
Client
NATS
Client
NATS
Client
Randomly distributed

42. Load Balanced Queues
SUB foo workers
PUB foo
NATS
Client
NATS
Client
NATS
Client
NATS
Client
Randomly distributed

43. Load Balanced Queues
SUB foo workers
PUB foo
NATS
Client
NATS
Client
NATS
Client
NATS
Client
Randomly distributed

44. Load Balanced Queues
SUB foo workers
PUB foo
NATS
Client
NATS
Client
NATS
Client
NATS
Client
Randomly distributed

45. Load Balanced Queues
SUB foo workers
PUB foo
NATS
Client
NATS
Client
NATS
Client
NATS
Client
Randomly distributed

46. Load Balanced Queues

47. Wildcards
SUB foo workers
PUB foo
NATS
Client
NATS
Client
NATS
Client
NATS
Client
NATS
Client
SUB >

48. Wildcards
SUB foo workers
PUB foo
NATS
Client
NATS
Client
NATS
Client
NATS
Client
NATS
Client
SUB >

49. Wildcards
SUB foo workers
PUB foo
NATS
Client
NATS
Client
NATS
Client
NATS
Client
NATS
Client
SUB >

50. Wildcards
SUB foo workers
PUB foo
NATS
Client
NATS
Client
NATS
Client
NATS
Client
NATS
Client
SUB >

51. Wildcards
SUB foo workers
PUB foo
NATS
Client
NATS
Client
NATS
Client
NATS
Client
NATS
Client
SUB >

52. Wildcards
SUB foo workers
PUB foo
NATS
Client
NATS
Client
NATS
Client
NATS
Client
NATS
Client
SUB >

53. Wildcards
SUB foo.bar workers
PUB foo.bar
NATS
Client
NATS
Client
NATS
Client
NATS
Client
SUB >
NATS
Client
SUB foo.*

54. Wildcards
SUB foo.bar workers
PUB foo.bar
NATS
Client
NATS
Client
NATS
Client
NATS
Client
SUB >
NATS
Client
SUB foo.*

55. Wildcards
SUB foo.bar workers
PUB foo.bar
NATS
Client
NATS
Client
NATS
Client
NATS
Client
SUB >
NATS
Client
SUB foo.*

56. Wildcards
SUB foo.bar workers
PUB foo.bar
NATS
Client
NATS
Client
NATS
Client
NATS
Client
SUB >
NATS
Client
SUB foo.*

57. Wildcards
SUB foo.bar workers
PUB foo.bar
NATS
Client
NATS
Client
NATS
Client
NATS
Client
SUB >
NATS
Client
SUB foo.*

58. Messages replay with
NATS Streaming (STAN)

59. Message replay with STAN
NATS
Streaming
Client
NATS
Streaming
Server
● A NATS Streaming Server can be attached to the NATS
network and provide persistence of messages.

60. Message replay with STAN

61. Message replay with STAN

62. Running NATS on Kubernetes

63. Running NATS on Kubernetes
How to deploy NATS with 1000 lines of YAML*
*Note: NATS itself is platform agnostic

64. Running NATS on Kubernetes
● Recommended minimum version is Kubernetes v1.12
● Using StatefulSets with headless service
or NATS Operator suggested

65. Global NATS Cluster Topology
sgp1 (DOKS / Digital Ocean)
eu-west-1 (EKS / AWS)
us-west2 (GKE / Google)

66. Global NATS Cluster Topology

67. ● Clients: 4222
● Routes: 6222
● Monitoring: 8222
● Leafnode: 7422
● Gateways: 7522
● Exporter: 7777 → 30900, 30901 (NodePort)
NATS Server Exposed Ports

68. NATS Docker Images

69. Creating a NATS Cluster

70. Configuration Reload

71. Connecting multiple
NATS Clusters using gateways

72. Decentralized Auth
with NKEYS & JWTs

73. Subject Isolation via Accounts
● Global account $G is the default subject namespace
● Multiple accounts and import/export services amongs them
● System account: special account to manage NATS itself

74. NKEYS + JWTs

75. NATS Streaming as a Leafnode
from a Super Cluster

76. Securing the cluster with TLS

77. Using cert-manager
https://github.com/jetstack/cert-manager

78. Monitoring via Prometheus

80. Done! Globally available and secure
NATS super cluster is now ready!

81. Questions?

82. Thanks!
https://natsio.slack.com
github.com/nats-io / @nats_io
https://nats.io
← Join the NATS community :)

83. Rate today’s session
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