Théo Devantoy

Community Manager

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<p><em>&gt; To learn more about Envbuilder’s use cases and benefits, check out our introductory blog post <a href="https://coder.com/blog/envbuilder-is-here-enable-developers-to-customize-their-environments-with-dev-con">here</a>!</em></p>

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<p>Envbuilder allows you to build development environments from a Dev Container on Docker and Kubernetes or OpenShift.</p>

<p>In this post, we’ll explore some examples. These examples assume you already have an existing dev container spec in the <code>.devcontainer</code> folder at the root of your project’s repository. If you don’t, check out VS Code’s <a href="https://code.visualstudio.com/docs/devcontainers/tutorial">Dev Containers Tutorial</a>.</p>

<h1>Vanilla Kubernetes</h1>

<h2>Quick example</h2>

<p>Here is an example Kubernetes manifest that shows how to spawn a Pod from the Dev Container spec available in our <a href="https://github.com/coder/envbuilder-starter-devcontainer">envbuilder-starter-devcontainer</a> repository and obtain an interactive Bash shell from it.</p>


<p>After applying the manifest (e.g., via <code>kubectl apply</code>), you should be able to run <code>kubectl exec --stdin --tty devcontainer -- bash</code> to get a bash session.</p>

<h2>Running Staging Environments in Dev Containers</h2>

<p>Running your staging environment using Dev Containers can have multiple benefits.</p>

<p>The main advantage is having all the debugging tools you know and love ready to start debugging any issues that may arise in the staging environment.</p>

<p>Additionally, this approach helps identify and eliminate any bugs or issues that might be present in the Dev Container spec.</p>

<p>In this example, we’ll run an ephemeral web server using Deno, but you can easily modify this manifest to run the staging environment for your project.</p>


<h2>Caching</h2>

<p>In both of these cases, the Dev Container will be built from scratch every time you start the pod, which is fine for prototyping but can become quite slow.</p>

<p>To speed up your builds, you can cache the layers of the image.</p>

<h3>Using a Container Registry</h3>

<p>Envbuilder supports caching layers in a container registry. To enable this, configure authentication to your registry and set the <code>ENVBUILDER_CACHE_REPO</code> environment variable.</p>

<p>See the “<a href="https://github.com/coder/envbuilder?tab=readme-ov-file#layer-caching">Layer Caching</a>” section in Envbuilder’s README for more information.</p>

<h3>Using a Volume</h3>

<p>Envbuilder also supports caching layers in a folder, but this method is only intended for testing. For production, it’s best to use a container registry.</p>

<p>You can mount a PersistentVolume to the Pod and pass its path in the <code>ENVBUILDER_LAYER_CACHE_DIR</code> environment variable.</p>

<h2>Conclusion</h2>

<p>Envbuilder streamlines the setup and management of development environments, making workflows more efficient and flexible. Whether for prototyping or production, it offers a powerful solution for modern development needs.</p>

<p>You can check out <a href="https://github.com/coder/envbuilder">EnvBuilder on Github</a>. Want a demo? <a href="https://coder.com/demo">Contact us</a>.</p>


In this post, we’ll explore how to use Envbuilder to build and push a dev container image on Kubernetes.

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