2nd/10_Wiki/Topics/Architecture/Cosmos_플랫폼_(Netflix).md

id, title, category, status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, verification_status, tags, raw_sources, last_reinforced, github_commit, tech_stack

id	title	category	status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	verification_status	tags	raw_sources	last_reinforced	github_commit	tech_stack
wiki-2026-0508-cosmos-플랫폼-netflix	Cosmos 플랫폼 (Netflix)	10_Wiki/Topics	verified	self	Netflix Cosmos Cosmos Platform Cosmos	none	A	0.85	applied	netflix media-processing workflow microservices		2026-05-10	pending	language framework java spring-boot

Cosmos 플랫폼 (Netflix)

매 한 줄

"매 Netflix 의 next-gen media computing platform". Reloaded (predecessor) 의 후계, 2018-2020 announce. Microservices + workflow orchestration + serverless functions 매 통합. Encoding, transcoding, content analysis, IMF processing 매 모든 media pipeline 의 backbone.

매 핵심

매 architecture (3 layers)

• Optimus (API layer) — external-facing service, business logic, request validation.
• Plato (Workflow layer) — Conductor-based workflow orchestration, retry, branching.
• Stratum (Functions layer) — serverless compute, Titus (container) 위 실행.

매 design 원칙

• Asynchronous everything — sync call 매 minimum, message-based.
• Schema-first — Protobuf gRPC 매 contract.
• Workflow as DSL — JSON workflow definition (Conductor).
• Function granularity — small, idempotent, stateless.
• Event-driven — Kafka, SQS 매 inter-service.

매 응용

1. Video encoding pipeline — source → multiple bitrates × codecs.
2. Image processing — title art, thumbnails, language variants.
3. Subtitle / caption processing.
4. Content quality control (QC) automation.
5. IMF (Interoperable Master Format) ingestion.

💻 패턴

Workflow definition (Plato / Netflix Conductor)

{
  "name": "encode_video_v3",
  "version": 3,
  "tasks": [
    {
      "name": "probe",
      "type": "FUNCTION",
      "function": "stratum:ffprobe",
      "inputParameters": { "url": "${workflow.input.sourceUrl}" }
    },
    {
      "name": "fan_out_encode",
      "type": "FORK_JOIN_DYNAMIC",
      "dynamicForkTasksParam": "encodeTasks"
    },
    {
      "name": "join_results",
      "type": "JOIN"
    },
    {
      "name": "publish",
      "type": "FUNCTION",
      "function": "stratum:publishToCDN"
    }
  ]
}

Stratum function (Java, Spring Boot)

@CosmosFunction(name = "ffprobe")
public class FfprobeFunction implements Function<ProbeRequest, ProbeResponse> {
    @Override
    public ProbeResponse apply(ProbeRequest req) {
        var info = Ffmpeg.probe(req.url());
        return new ProbeResponse(info.duration(), info.codec(), info.bitrate());
    }
}

Optimus service (gRPC)

service EncodeService {
  rpc StartEncode(EncodeRequest) returns (EncodeResponse);
  rpc GetStatus(StatusRequest) returns (stream StatusUpdate);
}

Titus container deployment

# titus job definition
applicationName: stratum-ffprobe
container:
  image: registry/stratum/ffprobe:v42
  resources:
    cpu: 4
    memoryMB: 8192
    gpu: 0
  env:
    COSMOS_FUNCTION_NAME: ffprobe

Event-driven trigger (Kafka)

@KafkaListener(topics = "media.uploaded")
public void onUpload(MediaUploadedEvent event) {
    workflowClient.start("encode_video_v3", Map.of(
        "sourceUrl", event.getUrl(),
        "movieId", event.getMovieId()
    ));
}

Idempotency key (function level)

@CosmosFunction(idempotencyKey = "${input.movieId}-${input.bitrate}")
public class EncodeFunction implements Function<EncodeReq, EncodeResp> { ... }

매 결정 기준

상황	Approach
Long-running multi-step media job	Plato workflow
Simple stateless transform	Stratum function
External-facing API	Optimus service
Realtime / sub-100ms	NOT Cosmos (sync RPC service 따로)

기본값: workflow for any multi-step media pipeline; functions for individual steps.

🔗 Graph

• 부모: Microservices · Workflow Orchestration
• 변형: AWS Step Functions · Temporal · Argo Workflows
• 응용: Netflix Encoding Pipeline · Conductor (Netflix)
• Adjacent: Titus (Netflix) · Spinnaker · Reloaded (Netflix)

🤖 LLM 활용

언제: workflow definition 생성, function template 생성, 운영 incident 매 root cause 분석. 언제 X: production workflow execution (deterministic 해야 함).

❌ 안티패턴

• Stateful function: scale 못 함, retry 깨짐.
• Long sync chain in Optimus: workflow 가야 할 것 매 sync call 로 묶음.
• No idempotency: retry 매 duplicate side-effect.
• Workflow too granular: orchestration overhead > work.

🧪 검증 / 중복

• Verified (Netflix Tech Blog 2020 Rebuilding Netflix Video Processing Pipeline with Microservices).
• 신뢰도 A.

🕓 Changelog

날짜	변경
2026-05-08	Phase 1
2026-05-10	Manual cleanup — full content covering Optimus/Plato/Stratum