[Performance] Container Startup Slow - Image Layer Extraction Takes Minutes

[anshul23102]

Description

Container startup is slow because image layer extraction takes minutes. No layer caching or optimization. Every container startup re-extracts all image layers from storage.

Steps to Reproduce

1. Start container with 1GB image
2. Container startup begins
3. All image layers extracted from scratch
4. Layer extraction takes 3-5 minutes
5. Container unavailable for minutes

Environment Information

• Image handling: Layer-based image system
• Extraction: Slow, no caching
• Storage: Image blob storage
• Startup: Blocking until extraction complete

Expected Behavior

• Layer caching on host
• Incremental extraction
• Container startup <10 seconds
• Background layer pulling

Actual Behavior

• No layer caching
• Full extraction every time
• 3-5 minute startup
• Blocking operation

Code Reference

• File: daemon/image_manager.rs
• Method: extract_layers() - no caching
• Missing: Layer cache
• Missing: Incremental extraction

Additional Context

Level 2 performance issue. Fix requires:

• Implementing layer caching
• Incremental extraction logic
• Background layer pulling
• Performance optimization

Suggested Labels

performance, optimization, container-startup, caching, scalability