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Developer Load lets you load a locally built extension into Rancher without publishing to a Helm repository. This is the recommended method for development and evaluation.
Make sure you’ve met the requirements before proceeding.
1

Build the extension

From the repository root:
yarn build-pkg pastures
This produces a UMD bundle in dist-pkg/pastures-0.1.0/.
2

Serve the built package

yarn serve-pkgs
This starts a local HTTP server at http://127.0.0.1:4500 serving the contents of dist-pkg/.
Keep this terminal running while you use the extension. Closing it will unload Pastures from Rancher.
3

Open the Extensions page in Rancher

In your Rancher Manager UI, click the ☰ hamburger menu and select Extensions.
4

Enable Developer Load

On the Extensions page, click the ⋮ (three-dot) menu in the top-right corner and select Enable Developer Load. Confirm when prompted.This enables the Developer Load banner at the top of the Extensions page.
5

Paste the extension URL

In the Developer Load input field, enter:
http://127.0.0.1:4500/pastures-0.1.0/pastures-0.1.0.umd.min.js
Click Load.
6

Verify the extension loaded

The Pastures sidebar items should appear immediately:
  • Advisories, Overview, Fleet Overview, Projects, Access Control, Workloads, Operations, Harvester, Infrastructure, AI Agents, Settings

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URL format

The Developer Load URL follows this pattern: 
http://<host>:<port>/<pkg-name>-<version>/<pkg-name>-<version>.umd.min.js
  • host — 127.0.0.1 when running locally, or the IP/hostname of the machine running yarn serve-pkgs
  • port — 4500 by default
  • pkg-name — pastures
  • version — matches the version in package.json (currently 0.1.0)
If Rancher is running in a VM or container, replace 127.0.0.1 with the host machine’s IP address that is reachable from the Rancher UI browser session.

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Troubleshooting

ProblemSolution
”Failed to load” errorVerify yarn serve-pkgs is running and the URL is reachable from your browser
Extension loads but no sidebar itemsHard-refresh the Rancher UI (Cmd/Ctrl + Shift + R)
CORS errors in consoleEnsure Rancher and the serve-pkgs host are on the same network or configure CORS headers
Extension not updating after rebuildRe-run yarn build-pkg pastures, then reload the extension in Rancher