Exploring Kubernetes API Versions with kubectl api-versions

The kubectl api-versions command in Kubernetes is used to retrieve the API versions that are available in the cluster. This information is crucial for understanding which resources and features are supported by the Kubernetes API server at any given time.

To begin exploring Kubernetes API versions, you can execute the following command:

        kubectl api-versions
    

This command returns a list of API group versions supported by the Kubernetes API server. For example:

        admissionregistration.k8s.io/v1
        apiextensions.k8s.io/v1
        apps/v1
        ...
    

Each line represents an API group followed by its version. To verify the command’s execution and output, you can simply run it in your terminal or command prompt connected to a Kubernetes cluster.

Additionally, you can specify a particular API group to see its versions. For instance, to list API versions specifically for the core resources:

        kubectl api-versions | grep core
    

This command filters and displays only the API versions related to core Kubernetes resources. Example output might include:

        admissionregistration.k8s.io/v1
        apps/v1
        authentication.k8s.io/v1
        ...
    

Furthermore, you can check the API versions for a specific resource type. For example, to view the API versions for Pods:

        kubectl api-versions | grep pods
    

This command retrieves the API versions related to Pods specifically. Sample output could be:

        apps/v1
        v1
        ...
    

If you’re interested in API versions related to custom resources, you can filter using “custom” as shown below:

        kubectl api-versions | grep custom
    

This command lists the API versions associated with custom resources. Output may include entries like:

        apiextensions.k8s.io/v1
        custom.metrics.k8s.io/v1beta1
        ...
    

For developers exploring newer Kubernetes features, retrieving alpha and beta versions is useful. Execute:

        kubectl api-versions | grep beta
    

This command fetches API versions marked as beta, which are experimental or under development. Example output might look like:

        admissionregistration.k8s.io/v1beta1
        apps/v1beta1
        ...
    

Additionally, if you’re managing CRDs (Custom Resource Definitions), check their supported API versions:

        kubectl api-versions | grep crd
    

This command specifically lists API versions relevant to CRDs. Output could include:

        apiextensions.k8s.io/v1
        custom.metrics.k8s.io/v1beta1
        ...
    

Lastly, for administrators needing information on deprecated API versions, use the following command:

        kubectl api-versions | grep deprecated
    

This command retrieves API versions that are marked as deprecated. Example output may show:

        extensions/v1beta1
        ...
    

Each of these examples demonstrates how kubectl api-versions can be utilized to explore and understand the Kubernetes API versions supported in your cluster.

Also check similar articles.

Understanding Kubernetes API Resources with kubectl api-resources
Generating Shell Completion Code with kubectl completion
Managing Kubernetes Annotations with kubectl annotate
Updating Kubernetes Labels with kubectl label
Building Kubernetes Customizations with kubectl kustomize