Eugene Bova "Dapr (Distributed Application Runtime) in a Microservices Architecture"
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This document provides an introduction to Dapr (Distributed Application Runtime), an open-source project initiated by Microsoft for building distributed applications. It discusses Dapr's architecture, building blocks like service invocation, pub/sub, state management and secrets APIs. It also covers hosting environments, SDKs, performance, pros and cons and deployment in Kubernetes with annotations.
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Eugene Bova "Dapr (Distributed Application Runtime) in a Microservices Architecture"
- 1. Introduction to Dapr (Distributed Application Runtime) Yevhen Bova 2021-02-25
- 2. 2 www.luxoft.com Short bio Java Developer at Luxoft 10 years of experience in Java Involved in the development of: A huge OSGI-baseddesktop application(600+ modules, 300+ third-partymodules) Server-side - microservices
- 4. 4 www.luxoft.com Project overview https://dapr.io/ Initiated by Microsoft Open-source project (MIT License) - https://github.com/dapr/dapr Initial version: 0.1 released in Oct 2019 Current version: v1.0 released on Feb 17
- 7. 7 www.luxoft.com Hosting environments • Self-hosted • Dapr runtime needs to be launched via CL • Kubernetes-hosted • Dapr side-car container injected into pod
- 10. 10 www.luxoft.com Launching locally dapr run --app-id myservice --app-port 8081 --app-protocol http -- java -Dserver.port=8081 -jar com.example.myservice.jar
- 12. 12 www.luxoft.com Service invocation API Features • All calls between Dapr applications can be made secure with mutual authentication (mTLS) • Supports calls across namespaces • Performs retries • Observability • All calls between applications are traced, and metrics are gathered to provide insights and diagnostics for applications • Uses W3C tracing context • Integrates with OpenTelemetry for tracing, metrics, and logs • Access Control Lists
- 14. 14 www.luxoft.com Pub/sub API The same file can be applied • locally • in k8s Configuration
- 15. 15 www.luxoft.com Pub/sub API Features • Guarantees at-least-once semantics for message delivery • Multiple subscribers with the same app ID • Message delivered to one instance • Multiple subscribers with different app ID • Message delivered to all subscribers • Topic scoping • Limit which application can publish or subscribe to topics • Messages are wrapped in CloudEvent format (if not already wrapped)
- 16. 16 www.luxoft.com Pub/sub API Components • Hazelcast • Redis Streams (5.0.0 or later) • NATS • Kafka • Azure Service Bus • RabbitMQ • Azure Event Hubs • GCP Pub/Sub • MQTT • Possible to provide custom backend via SPI
- 18. 18 www.luxoft.com State management API Features • Consistency • eventual consistency (default behavior) • strong consistency • Concurrency • first-write-wins (ETag support is required either by store or through Dapr emulation) • last-write-wins • Bulk operations • not transactional • transactional
- 19. 19 www.luxoft.com State management API Components Name CRUD Transactional (Supports Actors) ETag Aerospike ✅ ❌ ✅ Apache Cassandra ✅ ❌ ❌ Cloudstate ✅ ❌ ✅ Couchbase ✅ ❌ ✅ Hashicorp Consul ✅ ❌ ❌ Hazelcast ✅ ❌ ❌ Memcached ✅ ❌ ❌ MongoDB ✅ ✅ ❌ MySQL ✅ ✅ ✅ PostgreSQL ✅ ✅ ✅ Redis ✅ ✅ ✅ RethinkDB ✅ ✅ ✅ Zookeeper ✅ ❌ ✅ AWS, GCP, Azure stores…
- 20. 20 www.luxoft.com State management API Components • Dapr supports Redis 5 and later • Azure supports Redis 4 and 6
- 22. 22 www.luxoft.com Bindings API Components Name Input Binding Output Binding Status Apple Push Notifications (APN) ✅ Alpha Cron (Scheduler) ✅ ✅ Alpha HTTP ✅ GA InfluxDB ✅ Alpha Kafka ✅ ✅ Alpha Kubernetes Events ✅ Alpha MQTT ✅ ✅ Alpha MySQL ✅ Alpha PostgreSql ✅ Alpha Postmark ✅ Alpha RabbitMQ ✅ ✅ Alpha Redis ✅ Alpha SMTP ✅ Alpha Twilio ✅ Alpha Twitter ✅ ✅ Alpha SendGrid ✅ Alpha AWS, GCP, Azure, Alibaba…
- 24. 24 www.luxoft.com Secrets API Features • Can be accessed • Programmatically through API • In Dapr component configuration files • Secrets scoping • By default, any secret is accessible from any Dapr application • Each Dapr application can be configured to have access to only selected secrets
- 25. 25 www.luxoft.com Secrets API Components • Local environment variables • Local file • HashiCorp Vault • Kubernetes secrets • AWS Secret Manager • GCP Secret Manager • Azure Key Vault
- 26. 26 www.luxoft.com SDKs Language Status Client SDK Service Extensions Actor SDK .NET Stable ✔ ✔ ASP.NET Core ✔ Python Stable ✔ ✔ gRPC ✔ FastAPI Flask Java Stable ✔ ✔ Spring Boot ✔ Go Stable ✔ ✔ PHP Stable ✔ ✔ ✔ C++ In development ✔ Rust In development ✔ Javascript In development ✔
- 28. 28 www.luxoft.com Performance and scalability Overhead Test setup: • 1,000 requests per second • Sidecar limited to 0.5 vCPU • Sidecar mTLS enabled • Sidecar telemetry enabled (tracing with a sampling rate of 0.1) • Payload of 1KB • Dapr side car overhead (1,000 requests): • 0.48 vCPU • 23Mb • Control plane consumes: • In non-HA mode: 0.009 vCPU and 61.6 Mb • In HA mode: ~0.02 vCPU and 185 Mb
- 30. 30 www.luxoft.com Pros Simple workflows with pub/sub and stage management are easy to implement with Dapr No need to deal with different third-party SDK, drivers, etc. Encourages developers to use best practices Implementation of a component (store, pub-sub, etc) can be replaced easily Language-agnostic Well-documented API examples SDK examples Deployment examples
- 31. 31 www.luxoft.com Cons APIs provide a small subset of features of underlying components Restricts versions of underlying components Only Redis 5 and 6 are supported Makes it harder to launch/debug apps on the dev side Need to launch two processes instead of one (app + Dapr) Console log is cluttered No good support in IDE (yet?) Devs have to create launchers manually to launch Dapr Requires extra resources on server side (two-four pods) Adds complexity to the overall picture Overlaps with istio: mTLS, tracing Maturity status: A lot of components are in alpha/experimental state Low adaptation
- 32. 32 www.luxoft.com References Good overview - https://www.youtube.com/watch?v=MjyulcRqh20 Examples - https://github.com/dapr/quickstarts SDK examples - https://github.com/dapr/java-sdk/tree/master/examples/src/main/java/io/dapr/examples API reference - https://docs.dapr.io/reference/api/ Service Invocation Performance - https://docs.dapr.io/operations/performance-and-scalability/perf-service-invocation/
- 33. Thank You!