CubeSandbox
Instant, Concurrent, Secure & Lightweight Sandbox Service for AI Agents
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Cube Sandbox is a high-performance, out-of-the-box secure sandbox service built on RustVMM and KVM. It supports both single-node deployment and easy scaling to multi-node clusters. It is compatible with the E2B SDK and can create a hardware-isolated, fully serviceable sandbox in under 60ms with less than 5MB of memory overhead.
📰 News
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v0.6: K8s deploy, Volume framework, template aliases K8s deploy — Deploy Cube control-plane components and compute nodes on Kubernetes Volume framework — E2B-compatible Volume framework that lets users plug in custom backend storage Template aliases — Set an alias when creating a template, and create sandboxes by specifying that alias. Changelog → · K8s deploy → · Volume plugin → |
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v0.5: AutoPause, Terraform deployer, ARM64 & network policy hardening AutoPause/AutoResume — idle sandboxes auto-suspend and wake on the next request. Terraform one-click cluster deploy ARM64 native full-stack support network policy hardening — per-sandbox traffic tokens, policy-routing egress. Changelog → · Terraform deploy → |
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v0.4: Safer egress, easier ops Credential vault — Agents call external APIs as usual; keys never enter the sandbox. Dashboard — version matrix and template health checks; see at a glance whether templates need rebuilding after upgrades. Changelog → · Security proxy guide → · WebUI guide → |
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Snapshot, Clone & Rollback at hundred-millisecond granularity CubeSandbox 0.3.0 introduces the CubeCoW Copy-on-Write snapshot engine, enabling event-level snapshots, instant cloning, and rollback to any saved state. Changelog → |
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🎉 Initial open-source release Cube Sandbox is now open source! Millisecond boot, hardware-level isolation, E2B-compatible sandbox for AI Agents. Changelog → |
Product Highlights
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⚡ Ultra-fast Startup Resource pooling and snapshot cloning skip all cold-start overhead. Average <60ms cold start — sandbox creation faster than a blink. Quick start → |
🔒 Hardware Isolation Every sandbox runs a dedicated OS kernel in its own MicroVM. Architecture → |
🔌 E2B SDK Compatible Compatible with E2B SDK interface. Switch from E2B Cloud seamlessly by changing one environment variable — zero client code changes. Examples → |
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📦 High-density Deployment <5MB overhead per sandbox enables thousands of instances per server via kernel sharing and Copy-on-Write (CoW). Supports automatic sandbox pause and resume, further improving deployment density and cost optimization. Quick start → |
🛡️ Network Security eBPF-based inter-sandbox isolation and egress filtering at kernel level; built-in L7 security proxy enables per-domain/path/method policies with automatic credential injection — secrets never visible to sandbox code. Security proxy guide → |
📸 Flexible State Management High-frequency snapshot and rollback at hundred-millisecond granularity. Create checkpoints on running sandboxes, roll back to any saved state at any time, or fork from a specific state to explore in parallel. v0.3 changelog → |
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💾 Volume Framework E2B-compatible Volume framework that lets users plug in custom backend storage solutions. Volumes have an independent lifecycle and can be shared across sandboxes. Volume plugin → |
🚀 Production Deployment Deploy production clusters on Tencent Cloud with one click using Terraform. Also supports deployment on standard Kubernetes clusters (preview). Terraform deploy → · K8s deploy → |
💪 ARM Architecture Support Full native ARM64 support across compilation, build, and deployment workflows. Bare-metal deploy → |
Demos
1.cubesandbox.-.mp4 |
2.cubesandbox.demo.mp4 |
Cube-Sandbox.RL.demo.mp4 |
5.cube.V0.3.0.-.-.mp4 |
| Installation & Demo | Performance Test | RL (SWE-Bench) | Snapshot · Clone · Rollback |
Benchmarks
In the context of AI Agent code execution, CubeSandbox achieves the perfect balance of security and performance:
| Metric | Docker Container | Traditional VM | CubeSandbox |
|---|---|---|---|
| Isolation Level | Low (Shared Kernel Namespaces) | High (Dedicated Kernel) | Extreme (Dedicated Kernel + eBPF) |
| Boot Speed *Full-OS boot duration |
200ms | Seconds | Sub-millisecond (<60ms) |
| Memory Overhead | Low (Shared Kernel) | High (Full OS) | Ultra-low (Aggressively stripped, <5MB) |
| Deployment Density | High | Low | Extreme (Thousands per node) |
| E2B SDK Compatible | / | / | ✅ Drop-in |
- Cold start benchmarked on bare-metal. 60ms at single concurrency; under 50 concurrent creations, avg 67ms, P95 90ms, P99 137ms — consistently sub-150ms.
- Memory overhead measured with sandbox specs ≤ 32GB. Larger configurations may see a marginal increase.
For detailed metrics on startup latency and resource overhead, see the Core Operations Performance Benchmark Report (bare metal) and the PVM Cloud Server Benchmark Report.
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| Sub-150ms sandbox delivery under both single and high-concurrency workloads |
CubeSandbox base memory footprint across various instance sizes (*Blue: Sandbox specifications; Orange: Base memory overhead). Note that memory consumption increases only marginally as instance sizes scale up. |
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Quick Start
⚡ Millisecond-level startup — watch the fast-start flow above.
Cube Sandbox requires an x86_64 Linux environment with KVM support.
The guide walks you through everything in four steps — provisioning a server, installing Cube Sandbox, creating a sandbox template, and running your first agent code. No source build needed, up and running in minutes.
Choose your deployment path:
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🖥 PVM · Cloud VM →
🏆 Recommended |
🏗 Bare Metal → |
💻 Dev-Env →
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First thing after install: open the Web console
🖥️ Visual management — from overview to creating a sandbox and streaming logs, all in your browser.
After one-click deployment, open in your browser:
http://<control-node IP>:12088
Recommended three steps:
- Check overview — Open Overview, confirm nodes are Ready and capacity looks healthy
- Prepare a template — Install an official preset from Template Store; skip if you already have a
READYtemplate under Templates - Create a sandbox — Sandboxes → + New sandbox, pick a
READYtemplate, and view live logs on the detail page within seconds
See the full WebUI console guide.
Deep Dive
- Documentation Home — complete guide navigation
- ☁️ PVM Deployment — deploy on ordinary cloud VMs without bare metal or nested virtualization
- Template Concepts — image-to-template concepts and workflows
- Example Projects — hands-on examples (code execution, browser automation, OpenClaw integration, RL training, and more)
- 🖥️ WebUI Console — visual management right after install (
:12088) - 🔐 Security Proxy & Credential Vault — CubeEgress domain filtering, injection, and auditing
- 🤖 Digital Assistant AgentHub — create and manage OpenClaw assistants (Preview)
- 💻 Development Environment (QEMU VM) — no KVM access? Try Cube Sandbox inside a disposable OpenCloudOS 9 VM
Architecture
| Component | Responsibility |
|---|---|
| CubeAPI | High-concurrency REST API Gateway (Rust), compatible with E2B. Swap the URL for seamless migration. |
| CubeMaster | Cluster orchestrator. Receives API requests and dispatches them to corresponding Cubelets. Manages resource scheduling and cluster state. |
| CubeProxy | Reverse proxy, compatible with the E2B protocol, routing requests to the appropriate sandbox instances. |
| Cubelet | Compute node local scheduling component. Manages the complete lifecycle of all sandbox instances on the node. |
| CubeVS | eBPF-based virtual switch, providing kernel-level network isolation and security policy enforcement. |
| CubeEgress | OpenResty-based egress security gateway: L7 domain filtering, credential injection, and access auditing; works with CubeVS kernel policies so sandbox traffic cannot bypass inspection. |
| CubeHypervisor & CubeShim | Virtualization layer — CubeHypervisor manages KVM MicroVMs, CubeShim implements the containerd Shim v2 API to integrate sandboxes into the container runtime. |
👉 For more details, please read the Architecture Design Document and CubeVS Network Model.
Community & Contributing
We welcome contributions of all kinds—whether it's a bug report, feature suggestion, documentation improvement, or code submission!
- 🐞 Found a Bug or have questions? Submit an issue on GitHub Issues.
- 💡 Have an Idea? Join the conversation in GitHub Discussions.
- 🛠️ Want to Code? Check out our CONTRIBUTING.md to learn how to submit a Pull Request.
- 📝 Want to contribute docs? Submit bilingual PRs to our community doc channels: Troubleshooting, Use Cases, and Integrations. Additionally, the Cube 100 Program is now open — we're looking for the first 100 teams running AI agents in production with Cube. Limited to 100 seats. Learn more & apply →
- 💬 Want to Chat? Join our Discord.
Roadmap
Coming soon — see the full roadmap for details.
| Feature | Description |
|---|---|
| Kubernetes-Native Deployment | Evolve from Helm-based deployment toward CRD- and Operator-centric native management, with smooth upgrade capabilities |
| Cross-Node Pause & Resume | Suspend a sandbox on one node and resume it on another with full memory and filesystem state preserved |
| E2B API Compatibility | Close remaining gaps with the E2B specification for full drop-in compatibility |
| Control Plane / Data Plane Separation | Decouple the control plane from the data plane so control plane upgrades or failures never affect sandboxes already in flight |
| Sandbox Fault Recovery | Automatic detection and recovery of crashed VMs, stuck shim processes, and network partitions with configurable recovery policies |
| Scheduling & Operations Enhancements | Resource-aware placement, affinity rules, live rebalancing, and node drain with sandbox migration |
License
CubeSandbox is released under the Apache License 2.0.
The birth of CubeSandbox stands on the shoulders of open-source giants. Special thanks to Cloud Hypervisor, Kata Containers, virtiofsd, containerd-shim-rs, ttrpc-rust, and others. We have made tailored modifications to some components to fit the CubeSandbox execution model, and the original in-file copyright notices are preserved.
Cube Sandbox is listed in the CNCF Landscape.
