Kubeadm requires manual version updates of its current supported k8s
control plane version and minimally supported k8s control plane and
kubelet versions every release cycle.
To avoid that, in constants.go:
- Add the helper function getSkewedKubernetesVersion() that can be
used to retrieve a MAJOR.(MINOR+n).0 version of k8s. It currently
uses the kubeadm version populated in "component-base/version" during
the kubeadm build process.
- Use the function to set existing version constants (variables).
Update util/config/common.go#NormalizeKubernetesVersion() to
tolerate the case where a k8s version in the ClusterConfiguration
is too old for the kubeadm binary to use during code freeze.
Include unit tests for the new utilities.
Kubeadm no longer supports kube-dns and CoreDNS is the only
supported DNS server. Remove ClusterConfiguration.DNS.Type
from v1beta3 that is used to set the DNS server type.
of service subnets.
Update DNS, Cert, dry-run logic to support list of Service CIDRs.
Added unit tests for GetKubernetesServiceCIDR and updated
GetDNSIP() unit test to inclue dual-sack cases.
Some code in kubeadm was designed with the intent, that in the future CoreDNS
and kube-dns versions will match to specific K8s versions. This code is not
functional, since it does not perform any version matching. As of this moment,
no version matching is planned and a lot of boilerplate code is left useless.
The solution is simple - remove the unneeded parts to simplify the flow.
Signed-off-by: Rostislav M. Georgiev <rostislavg@vmware.com>
