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Deploy with youki

youki is an OCI container runtime written in Rust. youki has WasmEdge baked in. This chapter will walk you through deploying WASM images with youki.

Prerequisites

  1. Build and configure youki with WasmEdge support

    We will use Ubuntu 20.04 as an example. For other OS, please see here.

    Run the following command line to build and install youki on your machine.

    $ sudo apt-get install \
    curl \
    git \
    pkg-config \
    libsystemd-dev \
    libdbus-glib-1-dev \
    build-essential \
    libelf-dev \
    libzstd-dev \
    libseccomp-dev \
    libclang-dev

    # If you don't have the rust toolchain installed run:
    $ curl https://sh.rustup.rs -sSf | sudo sh -s -- -y

    Next, configure, build, and install a youki binary with WasmEdge support.

    git clone --recurse-submodules https://github.com/containers/youki.git
    cd youki
    ./scripts/build.sh -o . -r -f wasm-wasmedge
    ./youki -h
    export LD_LIBRARY_PATH=$HOME/.wasmedge/lib
  2. Install WasmEdge

  3. Configure the config.json from youki to run WASM modules.

    To run a webassembly module with youki, the config.json has to include either runc.oci.handler or module.wasm.image/variant=compat". It also needs you to specify a valid .wasm (webassembly binary) or .wat (webassembly test) module as an entrypoint for the container.

    "ociVersion": "1.0.2-dev",
    "annotations": {
    "run.oci.handler": "wasm"
    },
    "process": {
    "args": [
    "wasi_example_main.wasm",
    ],

Run a simple WebAssembly app

Now we can run a simple WebAssembly app. A separate article explains how to compile, package, and publish the WebAssembly program as a container image to Docker hub.

sudo ctr i pull docker.io/wasmedge/example-wasi:latest

Run the example with Youki and Podman.

sudo podman --runtime /PATH/WHARE/YOU/BUILT/WITH/WASM-WASMEDGE/youki run /wasi_example_main.wasm 50000000

That's it.