The document discusses stateful serverless computing and the CloudState project. It begins by outlining some technical requirements for building general-purpose applications in a serverless environment, including support for state management, distributed coordination, and predictable performance. It then introduces CloudState, an open-source project that aims to make stateful serverless applications easier to build by abstracting over complex distributed systems concerns like state management, databases, and infrastructure. CloudState provides client libraries in multiple languages and supports powerful state models and databases. It also handles operations when deployed as a managed service. The document concludes by describing CloudState's architecture, which uses Akka, gRPC, Kubernetes, and databases.

1. Jonas Bonér
@jboner
Towards
Stateful
Serverless

2. “We predict that Serverless Computing will grow
to dominate the future of Cloud Computing.”
- Berkeley CS Department
Cloud computing simplified: a Berkeley view on serverless computing

3. Serverless ≠Faas

4. FaaS
FaaS = Function-as-a-Service

5. Is visionary
FaaS
FaaS = Function-as-a-Service

6. Is visionary
Paved the way
FaaS
FaaS = Function-as-a-Service

7. Is visionary
Paved the way
Just the first step
FaaS
FaaS = Function-as-a-Service

8. Serverless is an Experience

9. good use-cases
For FaaS?

10. good use-cases
For FaaS?
Use-cases where throughput is key rather than low latency
and requests can be completed in a short time window

11. good use-cases
For FaaS?
1. Embarrassingly parallel processing tasks—invoked on demand & intermittently,
examples include: image processing, object recognition, log analysis
2. Low traffic applications—enterprise IT services, and spiky workloads
3. Stateless web applications—serving static content form S3 (or similar)
4. Orchestration functions—integration/coordination of calls to third-party services
5. Composing chains of functions—stateless workflow management, connected via
data dependencies
6. Job scheduling—CRON jobs, triggers, etc.
Use-cases where throughput is key rather than low latency
and requests can be completed in a short time window

12. FAAS: Hard to build
General-Purpose Applications

13. 1. Functions are stateless, ephemeral, short-lived:
expensive to lose computational context & rehydrate
2. Durable state is always “somewhere else”
3. No co-location of state and processing
4. No direct addressability—all communication over external storage
5. Limited options for managing & coordinating distributed state
6. Limited options for modelling data consistency guarantees
FAAS: Hard to build
General-Purpose Applications

14. General-purpose
applications in this new
Cloud Experience
We Want To Build

16. State

17. We Need Serverless Support For...

18. We Need Serverless Support For...

19. • Managing in-memory durable session state across individual requests
E.g. User Sessions, Shopping Carts, Caching
We Need Serverless Support For...

20. • Managing in-memory durable session state across individual requests
E.g. User Sessions, Shopping Carts, Caching
• Low-latency serving of dynamic in-memory models
E.g. Serving of Machine Learning Models
We Need Serverless Support For...

21. • Managing in-memory durable session state across individual requests
E.g. User Sessions, Shopping Carts, Caching
• Low-latency serving of dynamic in-memory models
E.g. Serving of Machine Learning Models
• Real-time stream processing
E.g. Recommendation, Anomaly Detection, Prediction Serving
We Need Serverless Support For...

22. • Managing in-memory durable session state across individual requests
E.g. User Sessions, Shopping Carts, Caching
• Low-latency serving of dynamic in-memory models
E.g. Serving of Machine Learning Models
• Real-time stream processing
E.g. Recommendation, Anomaly Detection, Prediction Serving
• Distributed resilient transactional workflows
E.g. Saga Pattern, Workflow Orchestration, Rollback/Compensating Actions
We Need Serverless Support For...

23. • Managing in-memory durable session state across individual requests
E.g. User Sessions, Shopping Carts, Caching
• Low-latency serving of dynamic in-memory models
E.g. Serving of Machine Learning Models
• Real-time stream processing
E.g. Recommendation, Anomaly Detection, Prediction Serving
• Distributed resilient transactional workflows
E.g. Saga Pattern, Workflow Orchestration, Rollback/Compensating Actions
• Shared collaborative workspaces
E.g. Collaborative Document Editing, Blackboards, Chat Rooms
We Need Serverless Support For...

24. • Managing in-memory durable session state across individual requests
E.g. User Sessions, Shopping Carts, Caching
• Low-latency serving of dynamic in-memory models
E.g. Serving of Machine Learning Models
• Real-time stream processing
E.g. Recommendation, Anomaly Detection, Prediction Serving
• Distributed resilient transactional workflows
E.g. Saga Pattern, Workflow Orchestration, Rollback/Compensating Actions
• Shared collaborative workspaces
E.g. Collaborative Document Editing, Blackboards, Chat Rooms
• Leader election, counting, voting
…and other distributed systems patterns/protocols for coordination
We Need Serverless Support For...

25. Technical Requirements

26. 1. Stateful long-lived addressable virtual components
Actors
Technical Requirements

27. 1. Stateful long-lived addressable virtual components
Actors
2. Options for distributed coordination and communication patterns
Pub-Sub, Point-To-Point, Broadcast—CRDTs, Sagas, etc.
Technical Requirements

28. 1. Stateful long-lived addressable virtual components
Actors
2. Options for distributed coordination and communication patterns
Pub-Sub, Point-To-Point, Broadcast—CRDTs, Sagas, etc.
3. Options for managing distributed state reliably at scale
Ranging from strong to eventual consistency (durable/ephemeral)
Technical Requirements

29. 1. Stateful long-lived addressable virtual components
Actors
2. Options for distributed coordination and communication patterns
Pub-Sub, Point-To-Point, Broadcast—CRDTs, Sagas, etc.
3. Options for managing distributed state reliably at scale
Ranging from strong to eventual consistency (durable/ephemeral)
4. Intelligent adaptive placement of stateful functions
Physical co-location of state and processing, sharding, and sticky routing
Technical Requirements

30. 1. Stateful long-lived addressable virtual components
Actors
2. Options for distributed coordination and communication patterns
Pub-Sub, Point-To-Point, Broadcast—CRDTs, Sagas, etc.
3. Options for managing distributed state reliably at scale
Ranging from strong to eventual consistency (durable/ephemeral)
4. Intelligent adaptive placement of stateful functions
Physical co-location of state and processing, sharding, and sticky routing
5. Predictable performance, latency, and throughput
In startup time, communication/coordination, and storage of data
Technical Requirements

31. 1. Stateful long-lived addressable virtual components
Actors
2. Options for distributed coordination and communication patterns
Pub-Sub, Point-To-Point, Broadcast—CRDTs, Sagas, etc.
3. Options for managing distributed state reliably at scale
Ranging from strong to eventual consistency (durable/ephemeral)
4. Intelligent adaptive placement of stateful functions
Physical co-location of state and processing, sharding, and sticky routing
5. Predictable performance, latency, and throughput
In startup time, communication/coordination, and storage of data
6. Ways of managing end-to-end guarantees and correctness
Technical Requirements

32. User Function
Deployment
FaaS Is Great At
Abstracting Over
Communication

33. Message In User Function
Deployment
FaaS Is Great At
Abstracting Over
Communication

34. Message In User Function
Deployment
Message Out
FaaS Is Great At
Abstracting Over
Communication

35. Message In User Function
Deployment
Message Out
FaaS With CRUD

36. Message In User Function
Deployment
Database
Message Out
FaaS With CRUD

37. Message In User Function
Deployment
Database
Message Out
Not Serverless
Leaky Abstraction

38. The Problem

39. If the Function manages the state, It is A
Black BoX
To the runtime
The Problem

40. The Problem

41. Unconstrained
database access
Makes it hard to
Automate
operations
The Problem

42. “Freedom is not so much the absence
of restrictions as finding the right ones,
the liberating restrictions.”
- Timothy keller

43. User Function
Deployment
FaaS
Abstracting Over
Communication

44. Message In
User Function
Deployment
FaaS
Abstracting Over
Communication

45. Message In
User Function
Deployment
Message Out
FaaS
Abstracting Over
Communication

46. Message In
User Function
Deployment
Message Out
Stateful Serverless
Abstracting Over State

47. Message In
User Function
Deployment
Message Out
Stateful Serverless
Abstracting Over State
State In

48. Message In
User Function
Deployment
Message Out
Stateful Serverless
Abstracting Over State
State In State Out

49. Enter

50. What Is CloudState?
https://cloudstate.io

51. Overview:
1. Open Source (Apache 2.0) project
What Is CloudState?
https://cloudstate.io

52. Overview:
1. Open Source (Apache 2.0) project
2. Makes Stateful Serverless applications easy
What Is CloudState?
https://cloudstate.io

53. Overview:
1. Open Source (Apache 2.0) project
2. Makes Stateful Serverless applications easy
3. Reference implementation for a standard (protocol and spec)
What Is CloudState?
https://cloudstate.io

54. Overview:
1. Open Source (Apache 2.0) project
2. Makes Stateful Serverless applications easy
3. Reference implementation for a standard (protocol and spec)
4. Let’s you focus on business logic, data model, and workflow
What Is CloudState?
https://cloudstate.io

55. What Is CloudState?
https://cloudstate.io

56. What Is CloudState?
https://cloudstate.io
Don’t worry about:
1. Managing: Complexities of Distributed and Concurrent systems

57. What Is CloudState?
https://cloudstate.io
Don’t worry about:
1. Managing: Complexities of Distributed and Concurrent systems
2. Managing: Distributed State—Consistency, Replication, Persistence

58. What Is CloudState?
https://cloudstate.io
Don’t worry about:
1. Managing: Complexities of Distributed and Concurrent systems
2. Managing: Distributed State—Consistency, Replication, Persistence
3. Managing: Databases, Service Meshes, and other infrastructure

59. What Is CloudState?
https://cloudstate.io
Don’t worry about:
1. Managing: Complexities of Distributed and Concurrent systems
2. Managing: Distributed State—Consistency, Replication, Persistence
3. Managing: Databases, Service Meshes, and other infrastructure
4. Managing: Message Routing, Scalability, Fail-over & Recovery

60. What Is CloudState?
https://cloudstate.io
Don’t worry about:
1. Managing: Complexities of Distributed and Concurrent systems
2. Managing: Distributed State—Consistency, Replication, Persistence
3. Managing: Databases, Service Meshes, and other infrastructure
4. Managing: Message Routing, Scalability, Fail-over & Recovery
5. Running & Operating your application

61. What Is CloudState?
https://cloudstate.io

62. Technical Highlights:
1. Polyglot: Client libs in JavaScript, Java, Go—with upcoming support for
Python, .NET, Rust, Swift, Scala
What Is CloudState?
https://cloudstate.io

63. Technical Highlights:
1. Polyglot: Client libs in JavaScript, Java, Go—with upcoming support for
Python, .NET, Rust, Swift, Scala
2. PolyState: Powerful state models—Event Sourcing, CRDTs, Key Value
What Is CloudState?
https://cloudstate.io

64. Technical Highlights:
1. Polyglot: Client libs in JavaScript, Java, Go—with upcoming support for
Python, .NET, Rust, Swift, Scala
2. PolyState: Powerful state models—Event Sourcing, CRDTs, Key Value
3. PolyDB: Supporting SQL, NoSQL, NewSQL and in-memory replication
What Is CloudState?
https://cloudstate.io

65. Technical Highlights:
1. Polyglot: Client libs in JavaScript, Java, Go—with upcoming support for
Python, .NET, Rust, Swift, Scala
2. PolyState: Powerful state models—Event Sourcing, CRDTs, Key Value
3. PolyDB: Supporting SQL, NoSQL, NewSQL and in-memory replication
4. Leveraging Akka, gRPC, Knative, GraalVM, running on Kubernetes
What Is CloudState?
https://cloudstate.io

66. CloudState helps you with
(when being a managed service)

67. • Pay-as-you-go:
• On-demand Instance Creation, Passivation, and Failover
• Autoscaling—up and down
CloudState helps you with
(when being a managed service)

68. • Pay-as-you-go:
• On-demand Instance Creation, Passivation, and Failover
• Autoscaling—up and down
• ZeroOps:
• Automation of Message Routing and Delivery
• Automation of State Management
• Service of Record—In-Memory Cluster Sharding, Co-location of Data & Processing
• Coordination State—Replication, Consistency
• Automation of Deployment, Provisioning, Upgrades
CloudState helps you with
(when being a managed service)

69. Cloudstate Architecture

70. Kubernetes Pod
Kubernetes Pod
Kubernetes Pod
Cloudstate Architecture

71. Kubernetes Pod
Kubernetes Pod
Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Cloudstate Architecture
User Function
(JavaScript, Go, Java,…)
User Function
(JavaScript, Go, Java,…)

72. Kubernetes Pod
Kubernetes Pod
Kubernetes Pod
Cloudstate Proxy
(Akka Sidecar)
User Function
(JavaScript, Go, Java,…)
Cloudstate Architecture
User Function
(JavaScript, Go, Java,…)
User Function
(JavaScript, Go, Java,…)

73. Kubernetes Pod
Kubernetes Pod
Kubernetes Pod
Cloudstate Proxy
(Akka Sidecar)
User Function
(JavaScript, Go, Java,…)
Cloudstate Architecture
User Function
(JavaScript, Go, Java,…)
User Function
(JavaScript, Go, Java,…)

74. Kubernetes Pod
Kubernetes Pod
Kubernetes Pod
Cloudstate Proxy
(Akka Sidecar)
User Function
(JavaScript, Go, Java,…)
Cloudstate Architecture
User Function
(JavaScript, Go, Java,…)
User Function
(JavaScript, Go, Java,…)
gRPC

75. Kubernetes Pod
Kubernetes Pod
Kubernetes Pod
Cloudstate Proxy
(Akka Sidecar)
User Function
(JavaScript, Go, Java,…)
Cloudstate Architecture
User Function
(JavaScript, Go, Java,…)
User Function
(JavaScript, Go, Java,…)
Datastore
(Cassandra, Postgres, Spanner,…)
gRPC

76. Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Kubernetes PodUser Function
(JavaScript, Go, Java,…)
Kubernetes Pod
User Function
(JavaScript, Go, Java,…)

77. Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Akka Sidecar
Kubernetes PodUser Function
(JavaScript, Go, Java,…)
Akka Sidecar
Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Akka Sidecar

78. Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Akka Sidecar
Akka Cluster
Kubernetes PodUser Function
(JavaScript, Go, Java,…)
Akka Sidecar
Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Akka Sidecar

79. Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Akka Sidecar
Akka Cluster
Kubernetes PodUser Function
(JavaScript, Go, Java,…)
Akka Sidecar
Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Akka Sidecar
HTTP

80. Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Akka Sidecar
Akka Cluster
Kubernetes PodUser Function
(JavaScript, Go, Java,…)
Akka Sidecar
Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Akka Sidecar
HTTP

81. Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Akka Sidecar
Akka Cluster
gRPC
Kubernetes PodUser Function
(JavaScript, Go, Java,…)
Akka Sidecar
Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Akka Sidecar
HTTP

82. Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Akka Sidecar
Akka Cluster
gRPC
Kubernetes PodUser Function
(JavaScript, Go, Java,…)
Akka Sidecar
Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Akka Sidecar
HTTP
Gossip, State replication, Routing
Gossip, State replication, Routing

83. Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Akka Sidecar
Akka Cluster
Datastore
(Cassandra, Postgres, Spanner,…)
gRPC
Kubernetes PodUser Function
(JavaScript, Go, Java,…)
Akka Sidecar
Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Akka Sidecar
HTTP
Gossip, State replication, Routing
Gossip, State replication, Routing

84. Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Akka Sidecar
Akka Cluster
Datastore
(Cassandra, Postgres, Spanner,…)
gRPC
Kubernetes PodUser Function
(JavaScript, Go, Java,…)
Akka Sidecar
gRPC
Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Akka Sidecar
HTTP
gRPC
Gossip, State replication, Routing
Gossip, State replication, Routing

85. Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Akka Sidecar
Akka Cluster
Datastore
(Cassandra, Postgres, Spanner,…)
gRPC
Kubernetes PodUser Function
(JavaScript, Go, Java,…)
Akka Sidecar
gRPC
Kubernetes Pod
User Function
(JavaScript, Go, Java,…)
Akka Sidecar
gRPC
HTTP
gRPC
Events
Gossip, State replication, Routing
Gossip, State replication, Routing

86. Akka Cluster state management

87. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar

88. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar

89. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar
•Actor-based Distributed Runtime
•Decentralized Masterless P2P
•Epidemic Gossiping, Self-healing
https://akka.io

90. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar
•Actor-based Distributed Runtime
•Decentralized Masterless P2P
•Epidemic Gossiping, Self-healing
https://akka.io
User FunctionUser Function
User Function
User Function
User Function
User Function
User Function

91. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar
•Actor-based Distributed Runtime
•Decentralized Masterless P2P
•Epidemic Gossiping, Self-healing
•State Sharding & Routing on Entity Key
https://akka.io
User FunctionUser Function
User Function
User Function
User Function
User Function
User Function

92. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar
•Actor-based Distributed Runtime
•Decentralized Masterless P2P
•Epidemic Gossiping, Self-healing
•State Sharding & Routing on Entity Key
(Key, State)
https://akka.io
User FunctionUser Function
User Function
User Function
User Function
User Function
User Function

93. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar
•Actor-based Distributed Runtime
•Decentralized Masterless P2P
•Epidemic Gossiping, Self-healing
•State Sharding & Routing on Entity Key
•Forwarding of Requests (if needed)
(Key, State)
https://akka.io
User FunctionUser Function
User Function
User Function
User Function
User Function
User Function

94. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar
•Actor-based Distributed Runtime
•Decentralized Masterless P2P
•Epidemic Gossiping, Self-healing
•State Sharding & Routing on Entity Key
•Forwarding of Requests (if needed)
(Key, State)
(Key, State)
https://akka.io
User FunctionUser Function
User Function
User Function
User Function
User Function
User Function

95. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar
•Actor-based Distributed Runtime
•Decentralized Masterless P2P
•Epidemic Gossiping, Self-healing
•State Sharding & Routing on Entity Key
•Forwarding of Requests (if needed)
•Co-Location of State & Processing
(Key, State)
(Key, State)
https://akka.io
User FunctionUser Function
User Function
User Function
User Function
User Function
User Function

96. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar
•Actor-based Distributed Runtime
•Decentralized Masterless P2P
•Epidemic Gossiping, Self-healing
•State Sharding & Routing on Entity Key
•Forwarding of Requests (if needed)
•Co-Location of State & Processing
•Backed by Event Log
(Key, State)
(Key, State)
https://akka.io
User FunctionUser Function
User Function
User Function
User Function
User Function
User Function

97. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Event Log
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar
•Actor-based Distributed Runtime
•Decentralized Masterless P2P
•Epidemic Gossiping, Self-healing
•State Sharding & Routing on Entity Key
•Forwarding of Requests (if needed)
•Co-Location of State & Processing
•Backed by Event Log
(Key, State)
(Key, State)
https://akka.io
User FunctionUser Function
User Function
User Function
User Function
User Function
User Function

98. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Event Log
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar
•Actor-based Distributed Runtime
•Decentralized Masterless P2P
•Epidemic Gossiping, Self-healing
•State Sharding & Routing on Entity Key
•Forwarding of Requests (if needed)
•Co-Location of State & Processing
•Backed by Event Log
•Automatic Failover, Rehydration, and
Rebalancing
(Key, State)
(Key, State)
https://akka.io
User FunctionUser Function
User Function
User Function
User Function
User Function
User Function

99. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Event Log
Akka Sidecar
Akka Sidecar
Akka Sidecar
•Actor-based Distributed Runtime
•Decentralized Masterless P2P
•Epidemic Gossiping, Self-healing
•State Sharding & Routing on Entity Key
•Forwarding of Requests (if needed)
•Co-Location of State & Processing
•Backed by Event Log
•Automatic Failover, Rehydration, and
Rebalancing
https://akka.io
User FunctionUser Function
User Function
User Function
User Function
User Function
User Function

100. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Event Log
Akka Sidecar
Akka Sidecar
Akka Sidecar
•Actor-based Distributed Runtime
•Decentralized Masterless P2P
•Epidemic Gossiping, Self-healing
•State Sharding & Routing on Entity Key
•Forwarding of Requests (if needed)
•Co-Location of State & Processing
•Backed by Event Log
•Automatic Failover, Rehydration, and
Rebalancing
https://akka.io
User FunctionUser Function
User Function
User Function
User Function
User Function
User Function

101. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Event Log
Akka Sidecar
Akka Sidecar
Akka Sidecar
•Actor-based Distributed Runtime
•Decentralized Masterless P2P
•Epidemic Gossiping, Self-healing
•State Sharding & Routing on Entity Key
•Forwarding of Requests (if needed)
•Co-Location of State & Processing
•Backed by Event Log
•Automatic Failover, Rehydration, and
Rebalancing
(Key, State)
https://akka.io
User FunctionUser Function
User Function
User Function
User Function
User Function
User Function

102. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Event Log
Akka Sidecar
Akka Sidecar
Akka Sidecar
•Actor-based Distributed Runtime
•Decentralized Masterless P2P
•Epidemic Gossiping, Self-healing
•State Sharding & Routing on Entity Key
•Forwarding of Requests (if needed)
•Co-Location of State & Processing
•Backed by Event Log
•Automatic Failover, Rehydration, and
Rebalancing
(Key, State)
(Key, State)
https://akka.io
User FunctionUser Function
User Function
User Function
User Function
User Function
User Function

103. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar
•In-memory Replication of State
•Gossiping State Changes
•Using CRDTs
•State Merged on Local Node
•Highly Available (N Replicas)
•Very Scalable
https://akka.io
User FunctionUser Function
User Function
User Function
User Function
User Function
User Function

104. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar
•In-memory Replication of State
•Gossiping State Changes
•Using CRDTs
•State Merged on Local Node
•Highly Available (N Replicas)
•Very Scalable
(Key, State)
https://akka.io
User FunctionUser Function
User Function
User Function
User Function
User Function
User Function

105. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar
•In-memory Replication of State
•Gossiping State Changes
•Using CRDTs
•State Merged on Local Node
•Highly Available (N Replicas)
•Very Scalable
(Key, State)
(Key, State)
(Key, State)
https://akka.io
User FunctionUser Function
User Function
User Function
User Function
User Function
User Function
(Key, State)
(Key, State)

106. Akka Cluster state management
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Cluster
Akka Sidecar
Akka Sidecar
Akka Sidecar
Akka Sidecar
•In-memory Replication of State
•Gossiping State Changes
•Using CRDTs
•State Merged on Local Node
•Highly Available (N Replicas)
•Very Scalable
https://akka.io
User FunctionUser Function
User Function
User Function
User Function
User Function
User Function

107. Cloudstate Uses Better Models
For Distributed State

108. battle-tested, Yet Constrained, models like:
Cloudstate Uses Better Models
For Distributed State

109. battle-tested, Yet Constrained, models like:
Cloudstate Uses Better Models
For Distributed State
Event
Sourcing

110. battle-tested, Yet Constrained, models like:
Cloudstate Uses Better Models
For Distributed State
Event
Sourcing CRDTs

111. battle-tested, Yet Constrained, models like:
Cloudstate Uses Better Models
For Distributed State
Event
Sourcing CRDTs Key
Value

112. Event
Sourced
Entities
Happy Path

113. Event
Sourced
Entities
Happy Path

114. Command
Event
Sourced
Entities
Happy Path

115. Command
Event
Sourced
Entities
Happy Path

116. Command
Event
Sourced
Entities
Happy Path
Command

117. Command
Event
Log
Event
Event
Sourced
Entities
Happy Path
Command

118. Command
Event
Event
Log
Event
Event
Sourced
Entities
Happy Path
Command

119. Command
Event
Event
Log
Event
Event
Sourced
Entities
Happy Path
Command
Memory Image

120. Event
Sourced
Entities
Happy Path

121. SAD Path, RECOVER FROM FAILURE
Event
Sourced
Entities

122. Event
Log
SAD Path, RECOVER FROM FAILURE
Event
Sourced
Entities

123. Event
Log
REPLAY EventS
SAD Path, RECOVER FROM FAILURE
Event
Sourced
Entities

124. Event
Log
REPLAY EventS
SAD Path, RECOVER FROM FAILURE
Command
Event
Sourced
Entities

125. Benefits of
Event Sourcing

126. Benefits of
Event Sourcing
✴ One single Source of Truth with All history

127. Benefits of
Event Sourcing
✴ One single Source of Truth with All history
✴ Allows for Memory Image (Durable In-Memory State)

128. Benefits of
Event Sourcing
✴ One single Source of Truth with All history
✴ Allows for Memory Image (Durable In-Memory State)
✴ Avoids the Object-relational mismatch

129. Benefits of
Event Sourcing
✴ One single Source of Truth with All history
✴ Allows for Memory Image (Durable In-Memory State)
✴ Avoids the Object-relational mismatch
✴ Allows others to Subscribe to state changes

130. Benefits of
Event Sourcing
✴ One single Source of Truth with All history
✴ Allows for Memory Image (Durable In-Memory State)
✴ Avoids the Object-relational mismatch
✴ Allows others to Subscribe to state changes
✴ Has good Mechanical sympathy (Single Writer Principle)

131. Deployment
Serverless
Event Sourcing

132. User Function/entity
Deployment
Serverless
Event Sourcing

133. User Function/entity
Deployment
Event Log In
Serverless
Event Sourcing

134. Command In
User Function/entity
Deployment
Event Log In
Serverless
Event Sourcing

135. Command In
User Function/entity
Deployment
Reply Out
Event Log In
Serverless
Event Sourcing

136. Command In
User Function/entity
Deployment
Reply Out
Event Log In Events OUt
Serverless
Event Sourcing

137. Command In
User Function/entity
Deployment
Reply Out
Event Log In Events OUt
Serverless
Event Sourcing

138. Convergent & Commutative Replicated Data Types - Shapiro et. al. 2011
Conflict-Free Replicated Data Types

139. CRDT
Convergent & Commutative Replicated Data Types - Shapiro et. al. 2011
Conflict-Free Replicated Data Types

140. CRDTStrong Eventual Consistency
Deterministic by Design
Data Types Contain Resolution Logic
Always Converge Correctly, Eventually
Replicated & Decentralized
Highly Available & Very Scalable
Convergent & Commutative Replicated Data Types - Shapiro et. al. 2011
Conflict-Free Replicated Data Types

141. Data types
Counters
Registers
Sets
Maps
Graphs
(that all compose)
CRDTStrong Eventual Consistency
Deterministic by Design
Data Types Contain Resolution Logic
Always Converge Correctly, Eventually
Replicated & Decentralized
Highly Available & Very Scalable
Convergent & Commutative Replicated Data Types - Shapiro et. al. 2011
Conflict-Free Replicated Data Types

142. CRDTs are…

143. CRDTs are…
Associative
Batch-insensitive
(grouping doesn't matter)
a+(b+c)=(a+b)+c

144. CRDTs are…
Associative
Batch-insensitive
(grouping doesn't matter)
a+(b+c)=(a+b)+c
Commutative
Order-insensitive
(order doesn't matter)
a+b=b+a

145. CRDTs are…
Associative
Batch-insensitive
(grouping doesn't matter)
a+(b+c)=(a+b)+c
Commutative
Order-insensitive
(order doesn't matter)
a+b=b+a
Idempotent
Retransmission-insensitive
(duplication does not matter)
a+a=a

146. Deployment
Serverless
CRDTs

147. User Function/entity
Deployment
Serverless
CRDTs

148. User Function/entity
Deployment
States/Deltas IN
Serverless
CRDTs

149. Message In
User Function/entity
Deployment
States/Deltas IN
Serverless
CRDTs

150. Message In
User Function/entity
Deployment
Message Out
States/Deltas IN
Serverless
CRDTs

151. Message In
User Function/entity
Deployment
Message Out
States/Deltas IN States/deltas OUT
Serverless
CRDTs

152. Message In
User Function/entity
Deployment
Message Out
States/Deltas IN States/deltas OUT
Serverless
CRDTs

153. Deployment
Serverless
CRUD
Using KeyValue

154. User Function/entity
Deployment
Serverless
CRUD
Using KeyValue

155. User Function/entity
Deployment
Snapshot In
(By Entity KEy)
Serverless
CRUD
Using KeyValue

156. Message In
User Function/entity
Deployment
Snapshot In
(By Entity KEy)
Serverless
CRUD
Using KeyValue

157. Message In
User Function/entity
Deployment
Message Out
Snapshot In
(By Entity KEy)
Serverless
CRUD
Using KeyValue

158. Message In
User Function/entity
Deployment
Message Out
Snapshot In
(By Entity KEy)
Snapshot out
(By Entity Key)
Serverless
CRUD
Using KeyValue

159. Example
CRDT Entity
Presence function in a chat app
github.com/cloudstateio/samples-java-chat

160. Protobuf Descriptor
defining service API and messages

161. syntax = "proto3";
import "cloudstate/entity_key.proto";
package cloudstate.samples.presence;
option java_package = "io.cloudstate.samples.presence";
option java_outer_classname = "PresenceProtos";
Protobuf Descriptor
defining service API and messages

162. syntax = "proto3";
import "cloudstate/entity_key.proto";
package cloudstate.samples.presence;
option java_package = "io.cloudstate.samples.presence";
option java_outer_classname = "PresenceProtos";
"// Messages
message User {
"// Entity key is the unique entity/function identifier
string name = 1 [(.cloudstate.entity_key) = true];
}
message OnlineStatus {
bool online = 1;
}
message Empty {
}
Protobuf Descriptor
defining service API and messages

163. syntax = "proto3";
import "cloudstate/entity_key.proto";
package cloudstate.samples.presence;
option java_package = "io.cloudstate.samples.presence";
option java_outer_classname = "PresenceProtos";
"// Messages
message User {
"// Entity key is the unique entity/function identifier
string name = 1 [(.cloudstate.entity_key) = true];
}
message OnlineStatus {
bool online = 1;
}
message Empty {
}
"// Service API
service Presence {
"// Connect the given user
rpc Connect(User) returns (stream Empty);
"// Monitor the online status of the given user
rpc Monitor(User) returns (stream OnlineStatus);
}
Protobuf Descriptor
defining service API and messages

164. CRDT Entity for online presence

165. @CrdtEntity
public class PresenceEntity {
private final Vote vote; "// Vote CRDT for this user. It’s auto replicated
"// and keeps track how each node has voted
private final String username; "// Entity Key (for sharding and routing)
public PresenceEntity(
Optional<Vote> vote, CrdtCreationContext ctx, @EntityId String username) { … }
}
CRDT Entity for online presence

166. @CrdtEntity
public class PresenceEntity {
private final Vote vote; "// Vote CRDT for this user. It’s auto replicated
"// and keeps track how each node has voted
private final String username; "// Entity Key (for sharding and routing)
public PresenceEntity(
Optional<Vote> vote, CrdtCreationContext ctx, @EntityId String username) { … }
}
public static void main(String""... args) {
new CloudState()
.registerCrdtEntity(…)
.start();
}
CRDT Entity for online presence

167. @CrdtEntity
public class PresenceEntity {
private final Vote vote; "// Vote CRDT for this user. It’s auto replicated
"// and keeps track how each node has voted
private final String username; "// Entity Key (for sharding and routing)
public PresenceEntity(
Optional<Vote> vote, CrdtCreationContext ctx, @EntityId String username) { … }
}
"// Here we implement the Protobuf Service API, our business logic
@CommandHandler
public void connect(StreamedCommandContext<Empty> ctx) {
vote.vote(true); "// Set the user to online
ctx.onCancel(cancelled "-> { "// Register cancel callback for user disconnect
vote.vote(false);
});
…
}
public static void main(String""... args) {
new CloudState()
.registerCrdtEntity(…)
.start();
}
CRDT Entity for online presence

168. @CrdtEntity
public class PresenceEntity {
private final Vote vote; "// Vote CRDT for this user. It’s auto replicated
"// and keeps track how each node has voted
private final String username; "// Entity Key (for sharding and routing)
public PresenceEntity(
Optional<Vote> vote, CrdtCreationContext ctx, @EntityId String username) { … }
}
"// Here we implement the Protobuf Service API, our business logic
@CommandHandler
public void connect(StreamedCommandContext<Empty> ctx) {
vote.vote(true); "// Set the user to online
ctx.onCancel(cancelled "-> { "// Register cancel callback for user disconnect
vote.vote(false);
});
…
}
public static void main(String""... args) {
new CloudState()
.registerCrdtEntity(…)
.start();
}
CRDT Entity for online presence
@CommandHandler
public OnlineStatus monitor(StreamedCommandContext<OnlineStatus> ctx) {
ctx.onChange(change "-> { "// Subscribe to Vote CRDT changes
…
});
…
}

169. Run in Kubernetes
This step is not needed when user Cloudstate as a Service (as intended)

170. # Install Cloudstate
kubectl create namespace cloudstate
Run in Kubernetes
This step is not needed when user Cloudstate as a Service (as intended)

171. # Install Cloudstate
kubectl create namespace cloudstate
kubectl apply -n cloudstate -f https:"//github.com/
cloudstateio/cloudstate/releases/download/v0.4/
cloudstate-0.4.yaml
Run in Kubernetes
This step is not needed when user Cloudstate as a Service (as intended)

172. # Install Cloudstate
kubectl create namespace cloudstate
kubectl apply -n cloudstate -f https:"//github.com/
cloudstateio/cloudstate/releases/download/v0.4/
cloudstate-0.4.yaml
Run in Kubernetes
# Install our Presence app and Gateway
kubectl apply -f https:"//raw.githubusercontent.com/
cloudstateio/samples-java-chat/master/deploy/
presence.yaml
This step is not needed when user Cloudstate as a Service (as intended)

173. # Install Cloudstate
kubectl create namespace cloudstate
kubectl apply -n cloudstate -f https:"//github.com/
cloudstateio/cloudstate/releases/download/v0.4/
cloudstate-0.4.yaml
Run in Kubernetes
# Install our Presence app and Gateway
kubectl apply -f https:"//raw.githubusercontent.com/
cloudstateio/samples-java-chat/master/deploy/
presence.yaml
kubectl apply -f https:"//raw.githubusercontent.com/
cloudstateio/samples-java-chat/master/deploy/
gateway.yaml
This step is not needed when user Cloudstate as a Service (as intended)

174. # Install Cloudstate
kubectl create namespace cloudstate
kubectl apply -n cloudstate -f https:"//github.com/
cloudstateio/cloudstate/releases/download/v0.4/
cloudstate-0.4.yaml
Run in Kubernetes
# Install our Presence app and Gateway
kubectl apply -f https:"//raw.githubusercontent.com/
cloudstateio/samples-java-chat/master/deploy/
presence.yaml
kubectl apply -f https:"//raw.githubusercontent.com/
cloudstateio/samples-java-chat/master/deploy/
gateway.yaml
# Scale up the app to 3 nodes
kubectl scale deploy/presence-deployment "--replicas 3
This step is not needed when user Cloudstate as a Service (as intended)

175. Try out the
Next Generation
Stateful Serverless
cloudstate.io

176. lightbend.com/free-academy