Envoy Internals Deep Dive
summary
Explains how Envoy is built as a single-process, per-core worker data plane with a lightweight main thread and no thread pools, using an embarrassingly parallel model. Describes concrete mechanisms: RCU + TLS for lock-free cluster/route updates, TLS histogram flipping for merges, and a hot restart protocol that shares stats via shared-memory stats and passes sockets so binary or config reloads preserve connections. Claims scale to many hardware threads, supports HTTP/2 gRPC Redis MongoDB, and runs in production at Lyft.
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chapters (20)
- 0:00Start
- 0:40Agenda
- 4:33Service Config Discovery
- 5:19Observability
- 6:32High-Level Architecture Diagram of Envoy
- 6:49Connection Processing
- 8:00Http Connection Manager Filter
- 8:45Router Filter
- 8:58Cluster Manager
- 9:42Parallel Managers
- 10:02Discovery Service Api
- 12:05Multiple Connections per Thread
- 13:02Core of Envoy
- 13:42Main Thread
- 25:14Hot Restart
- 25:49Rolling Deploy
- 32:04Scope
- 34:30Flush the Cache
- 35:00Tls Histograms
- 36:04Summary
