Add-ons are unavailable because the local Kubernetes environment is missing

Issue Description

Add-ons are only available on when Portainer Server is installed on a Kubernetes environment. Portainer determines whether an install qualifies by checking for a local Kubernetes environment. If this environment doesn't exist, add-ons are gated, even if every other environment in your instance is Kubernetes.

If you have deleted your local Kubernetes environment, add-ons will remain unavailable until the local environment is recreated.

Workaround

Back up your Portainer instance first.

As a workaround, you can recreate the local environment using the API.

Send a request to the /api/endpoints endpoint, specifying EndpointCreationType=5 (Local Kubernetes). Replace $PORTAINER_URL and $ADMIN_TOKEN with your Portainer URL and an administrator API token respectively.

curl -sf -X POST "$PORTAINER_URL/api/endpoints" \
  -H "X-API-Key: $ADMIN_TOKEN" \
  -F "Name=local" \
  -F "EndpointCreationType=5"

The name you give the environment doesn't matter. Portainer only checks the environment type, so you can name it anything you like. If you already have an environment named local (for example, a leftover Docker environment), consider giving the new environment a different name to avoid confusion. Once you've recreated the local Kubernetes environment, add-ons should be available to install.