Kubernetes Versions

Unlike the lower-level Kubernetes Python Client, a single version of the kuber library contains multiple Kubernetes API version targets within a single installation. When loading/creating resources or resource bundles, the desired version of Kubernetes can be specified.

Specifying Versions

Kubernetes versions in kuber can be specified in two interchangeable ways:

• Version Labels: Versions can be specified as strings, e.g. "1.20", or
• KubernetesVersion: an object that contains the version label string along with other version related information.

In most cases, either of these can used. If the version label is used, it will be converted to a KubernetesVersion object internally.

Explicit Versions

Explicit Kubernetes versions in kuber are represented by the Major_Minor version syntax and prefixed with a v, e.g. v1.20 for version 1.20.x. The latest available patch level for each Kubernetes version will always be used when generating the configuration subpackages in kuber. Patch level distinctions are ignored by kuber because the configuration API is consistent across patch versions.

For example, to using Kubernetes version 1.20 in kuber would look like:

from kuber.v1.20 import core_v1

service = core_v1.Service()
config_map = core_v1.ConfigMap()

Or when dealing with resource bundles, the version is specified when creating the bundle and that version will be used by all resources loaded by that bundle:

import kuber

bundle = kuber.from_directory(
    "./foo/",
    kubernetes_version="1.20"
)

Floating Versions

To keep pace with the ongoing development of Kubernetes there are also two special versions available, latest and pre that will float from version to version over time. The latest version will always point to the most recent stable version of Kubernetes available at the time the library was published. Similarly, the pre version will always point to the latest pre-release (alpha or beta) version of Kubernetes available at the time of publishing.

These special version can be used in exactly the same way as the explicit versions within kuber:

import kuber
from kuber.latest import core_v1

service = core_v1.Service()
config_map = core_v1.ConfigMap()

bundle = kuber.create_bundle("latest")
bundle.add(service, config_map)

or for the pre-release version:

from kuber.pre import core_v1

service = core_v1.Service()
config_map = core_v1.ConfigMap()

bundle = kuber.create_bundle("pre")
bundle.add(service, config_map)

To find out the specific version information for any versions, explicit or floating, you can import that version of the package and print the version info object constant in that module. For example, to find out the specific version of the pre subpackage:

from kuber import pre

print(pre.KUBERNETES_VERSION.version)

Cluster-based Versioning

Often times it is most useful to write configurations that use the version of the cluster in which they will be deployed instead of hard-coding a version - even if it is a floating one. For that, kuber has a convenience function that returns a KubernetesVersion object, which can be used in place of a hard-coded version value. The function will connect to the currently configured cluster and return the KubernetesVersion object that best matches the cluster version.

In the f

import kuber

# Establich connection to the cluster currently
# configured in the local `.kubeconfig` file.
kuber.load_access_config()

# Get the version of the connected cluster or
# default to version 1.20 if unable to fetch
# version data from the cluster.
cluster_version = kuber.get_version_from_cluster("1.20")

# Use the returned `KubernetesVersion` object
# as the version for the cluster.
bundle = kuber.from_directory(
    "./foo/",
    kubernetes_version=cluster_version
)