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Gardener Extension for OpenStack provider

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Project Gardener implements the automated management and operation of Kubernetes clusters as a service. Its main principle is to leverage Kubernetes concepts for all of its tasks.

Recently, most of the vendor specific logic has been developed in-tree. However, the project has grown to a size where it is very hard to extend, maintain, and test. With GEP-1 we have proposed how the architecture can be changed in a way to support external controllers that contain their very own vendor specifics. This way, we can keep Gardener core clean and independent.

This controller implements Gardener’s extension contract for the OpenStack provider.

An example for a ControllerRegistration resource that can be used to register this controller to Gardener can be found here.

Please find more information regarding the extensibility concepts and a detailed proposal here.

Supported Kubernetes versions

This extension controller supports the following Kubernetes versions:

VersionSupportConformance test results
Kubernetes v1.24 Conformance Tests
Kubernetes v1.23 Conformance Tests
Kubernetes v1.22 Conformance Tests
Kubernetes v1.21 Conformance Tests
Kubernetes v1.20 Conformance Tests
Kubernetes v1.19 Conformance Tests
Kubernetes v1.18 Conformance Tests
Kubernetes v1.17 Conformance Tests
Kubernetes v1.16 Conformance Tests

[1] Conformance tests are still executed and validated, unfortunately no longer shown in TestGrid.

Please take a look here to see which versions are supported by Gardener in general.


The following lists known compatibility issues of this extension controller with other Gardener components.

OpenStack ExtensionGardenerActionNotes
< v1.12.0> v1.10.0Please update the provider version to >= v1.12.0 or disable the feature gate MountHostCADirectories in the Gardenlet.Applies if feature flag MountHostCADirectories in the Gardenlet is enabled. This is to prevent duplicate volume mounts to /usr/share/ca-certificates in the Shoot API Server.

How to start using or developing this extension controller locally

You can run the controller locally on your machine by executing make start.

Static code checks and tests can be executed by running make verify. We are using Go modules for Golang package dependency management and Ginkgo/Gomega for testing.

Feedback and Support

Feedback and contributions are always welcome. Please report bugs or suggestions as GitHub issues or join our Slack channel #gardener (please invite yourself to the Kubernetes workspace here).

Learn more!

Please find further resources about out project here: