Agent Skills
› serithemage/serverless-openclaw
› cold-start
cold-start
GitHub提供冷启动优化参考，涵盖Docker镜像精简、Fargate CPU调优、SOCI懒加载及Lambda Bedrock发现修复，旨在显著降低容器与函数的启动延迟并减小镜像体积。
Trigger Scenarios
优化应用或容器的冷启动性能
分析并减少Docker镜像大小
调整Fargate或Lambda的资源配置以改善启动时间
Install
npx skills add serithemage/serverless-openclaw --skill cold-start -g -y
SKILL.md
Frontmatter
{
"name": "cold-start",
"description": "References cold start optimization history and techniques. Covers Docker image optimization, Fargate CPU tuning, SOCI lazy loading, and Lambda Bedrock discovery fix. Use when optimizing startup performance.",
"allowed-tools": "Read, Glob, Grep"
}
Cold Start Optimization Reference
Full analysis: docs/cold-start-optimization.md
Results Summary
| Target | Before | After | Savings |
|---|---|---|---|
| Docker image size | 2.22 GB | 1.27 GB | 43% reduction |
| Fargate cold start | ~120s (0.25 vCPU) | ~40-57s (1 vCPU) | ~80s |
| Lambda cold start | 56s | 1.35s | ~54s |
Measurement Commands
make cold-start # Full measurement (stops tasks + cleans TaskState first)
make cold-start-warm # Warm start measurement (skip idle wait)
make task-status # Verify task state before measuring
make task-stop # Stop all tasks
make task-stop-recent # Stop only most recent task
Important: Always use make cold-start — never run the measurement script directly without stopping existing tasks first.
Docker Image Optimizations (Fargate)
| Optimization | Savings | Technique |
|---|---|---|
| Remove AWS CLI | -358 MB | Replaced aws s3 sync with @aws-sdk/client-s3 Node.js code (s3-sync.ts) |
| chown layer optimization | -134 MB | COPY --chown=openclaw:openclaw instead of separate RUN chown |
| Pre-generated openclaw config | — | Handled in Dockerfile (skip runtime onboard) |
| start-openclaw.sh simplification | — | Removed S3 restore/onboard/sleep 2 |
| zstd compression (P6) | -16% (258→217 MB) | --compression zstd in docker buildx |
SOCI Lazy Loading
./scripts/deploy-image.sh --soci # Linux only, ~50% additional pull-time reduction
SOCI CI: .github/workflows/deploy-image.yml
Fargate CPU Tuning (P7)
| CPU | Memory | Cold Start |
|---|---|---|
| 0.25 vCPU | 512 MB | OOM Kill |
| 0.25 vCPU | 2048 MB | ~120s |
| 0.5 vCPU | 2048 MB | ~80s |
| 1 vCPU | 2048 MB | ~40-57s (default) |
| 2 vCPU | 4096 MB | Configurable via env |
Configure via env vars: FARGATE_CPU, FARGATE_MEMORY
Container Startup Parallelization
- S3 restore + History load run via
Promise.all(~3-5s saved) - IP discovery runs non-blocking (Bridge starts serving while discovery continues)
- Stale IP fix: Bridge HTTP timeout 10s→3s, fallback to PendingMessages on failure
Lambda Cold Start (Phase 2 — The Biggest Win)
Root cause: Bedrock auto-discovery scanned all AWS regions on startup → 56s delay
Fix: bedrockDiscovery.enabled: false in OpenClaw config → 1.35s cold start
{
"bedrockDiscovery": { "enabled": false }
}
Lambda Optimization Techniques
runEmbeddedPiAgent()— bypasses Gateway WS server (no :18789 socket bind)extensionAPI.jsviafile://URL (not in exports map)- HOME=/tmp (Lambda read-only filesystem)
- Sessions in /tmp (ephemeral, acceptable for Lambda)
- No S3 session restore (Lambda starts fresh each cold start)
OpenClaw Version Impact on Cold Start
| Version | Cold Start | Status |
|---|---|---|
| v2026.2.9 | 65.3s | Working |
| v2026.2.13 | 57.9s | Working — pinned |
| v2026.2.14 | N/A | BROKEN (scope system) |
Pin location: packages/container/Dockerfile
ARG OPENCLAW_VERSION=2026.2.13
Configurable via build-arg or env var.
Watchdog Dynamic Timeout
- Active hours: 30-min idle timeout
- Inactive hours: 10-min idle timeout
- Based on CloudWatch activity metrics
- Watchdog skips pre-warmed tasks where
now < prewarmUntil
Version History
- 504300d Current 2026-07-25 09:02
