Adapting Kubernetes controllers to the edge: on-demand control planes using Wasm and WASI
Merlijn Sebrechtsa b, Tim Ramlota b, Sander Bornya b, Tom Goethalsa b, Bruno Volckaerta b, Filip De Turcka b
- aGhent University - Imec,IDLab,Department of Information Technology (Intec),Belgium
- bDepartment of Information Technology (Intec), IDLab, Ghent University - Imec, Belgium
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Abstract
Kubernetes’ high resource requirements hamper its adoption in constrained environments such as the edge and fog. Its extensible control plane is a significant contributor to this, consisting of long-lived processes called "controllers" that constantly listen for state changes and use resources even when they are not needed. This paper presents a WebAssembly-based framework for running lightweight controllers on-demand, only when they are needed. This framework extends the WebAssembly System Interface (WASI), in order to run Kubernetes controllers as lightweight Wasm modules. The framework runs these Wasm controllers in a modified version of Wasmtime, the reference WebAssembly (Wasm) runtime, that swaps idle controllers to disk and activates them when needed. A thorough evaluation shows this framework achieves a 64% memory reduction compared to traditional container-based controller frameworks.
TL;DRThis paper presents a WebAssembly-based framework for running lightweight controllers on-demand, only when they are needed, in a modified version of Wasmtime, the reference WebAssembly (Wasm) runtime. (Semantic Scholar)