[ELASTIC Demo Series] Wasm-operator – Efficient Kubernetes Orchestration with WebAssembly

Kubernetes operators have become a fundamental building block for automating lifecycle management of cloud-native applications. They enable users to extend the Kubernetes control plane with custom logic, but the traditional way of building operators as containerized microservices comes with limitations that become especially pronounced in resource-constrained or latency-sensitive environments, such as edge nodes or 6G multi-access edge deployments.

To address these challenges, imec has developed a new approach: the Wasm-operator, a Kubernetes operator platform built using WebAssembly (Wasm) instead of Docker containers. This novel architecture, designed and further developed as part of the ELASTIC Project, brings substantial gains in memory efficiency, security, and scalability, and is now publicly available as an open source prototype.

Why Containers Aren’t Always Good Enough for Operators

Kubernetes operators work by continuously reconciling desired state with actual cluster state. In the container-based model:

  • Every operator is deployed as one or more long-running pods

  • Even when idle, a container consumes RAM, CPU, and storage

  • Scaling the number of operators increases overhead significantly

This model works in large data centers, but in edge setups where many operators may be managing independent workloads, simply deploying everything as persistent containers becomes impractical or inefficient.

This is where WebAssembly offers a compelling alternative.

Why WebAssembly for Operators

WebAssembly (Wasm) is a portable, sandboxed execution format initially designed for the web, but now expanding into cloud, edge, and serverless environments. Compared to containers, Wasm components offer:

  • Smaller runtime footprint: Minimal memory usage, with fast startup times

  • Strong isolation: Secure sandboxing without requiring heavy virtualization

  • Dynamic loading/unloading: Wasm modules can be swapped in and out of memory based on demand

  • Language flexibility: Write operators in Rust, Go, C/C++, and other supported languages

  • Cross-platform portability: Run consistently across CPU architectures and environments

In short, Wasm enables a “sleep until needed” execution model that makes it ideal for Kubernetes operators that respond to events rather than run continuously.

The Wasm-Operator Architecture

The Wasm-operator introduces a fundamentally different approach to operator execution:

✅ Operators as Wasm Components

Each operator is compiled into a Wasm module and loaded into a shared Wasm runtime, instead of running in separate containers.

✅ Event-Based Execution

The runtime wakes up each operator only when a relevant watch or reconciliation event is triggered. No background loops and no constant CPU usage.

✅ Rust + Wasmtime Technology Stack

Operators are developed in Rust and executed using the Wasmtime runtime, balancing high performance, memory safety, and a reduced attack surface.

✅ Swapping Idle Operators to Disk

When operators are idle, they are swapped to disk to recover memory. They can be reloaded instantly when needed, reducing runtime overhead.

✅ Shared Runtime for Multiple Operators

Instead of each operator having its own container, the Wasm-operator allows multiple operators to coexist inside a single runtime environment, drastically reducing resource consumption.

What the Demo Shows

The demo video illustrates:

  • How Wasm-based operators are deployed on a Kubernetes cluster

  • Reactive, just-in-time loading and execution of operators

  • Swapping inactive operators to disk in order to free memory

  • Efficient reconciliation without continuous resource use

This highlights the core insight: operators do not need to stay in memory or consume CPU constantly. They can exist as lightweight Wasm components, activated only when necessary.

Why This Matters for Edge and 6G Systems

The Wasm-operator is well-suited for modern edge-native and 6G scenarios, where:

  • Devices have strict power and memory constraints

  • Nodes may be disconnected or battery-powered

  • Real-time or near-real-time decisions require local automation

  • Large numbers of fine-grained workloads must be orchestrated

By removing the need for persistent containers and enabling instant-on operators, this approach improves:

  • Operator density per device

  • System responsiveness

  • Memory and energy efficiency

  • Manageability and multi-tenancy

Try It Yourself

To install and experiment with the Wasm-operator on your own Kubernetes cluster, follow the official guides from the repository:

• Installation guide: https://github.com/idlab-discover/wasm-operator/blob/main/docs/setup.md
• Usage examples: https://github.com/idlab-discover/wasm-operator/blob/main/docs/usage.md

📌 Repository: https://github.com/idlab-discover/wasm-operator

What’s Next?

Work is ongoing to expand the Wasm-operator’s capabilities, including:

  • Better integration with the Go-based Kubernetes SDK.
  • Support for operators that contact external non-Kubernetes services for things like metrics.

Contributions and feedback are welcome.