eb658d699a
Automatic merge from submit-queue (batch tested with PRs 54160, 54016). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>. Fix `kubeadm upgrade plan` for offline operation **What this PR does / why we need it**: This PR allows `kubeadm upgrade plan` to work in firewalled/offline/otherwise restricted environments by ignoring errors when trying to reach dl.k8s.io. Instead, we fall back to the current kubeadm version as the latest stable version. This is a reasonable as a user is [expected to install a recent version of kubeadm before upgrading](https://kubernetes.io/docs/tasks/administer-cluster/kubeadm-upgrade-1-8/#upgrading-your-control-plane). **Which issue this PR fixes**: Fixes kubernetes/kubeadm#498 **Special notes for your reviewer**: Should preferably be cherrypicked to 1.8. ```release-note Fix `kubeadm upgrade plan` for offline operation: ignore errors when trying to fetch latest versions from dl.k8s.io ```