Default Go HTTP transport does not allow to use CIDR notations in
NO_PROXY variables, thus for certain HTTP calls that is done inside
kubeadm user needs to put explicitly multiple IP addresses. For most of
calls done via API machinery it is get solved by setting different Proxy
resolver. This patch allows to use CIDR notations in NO_PROXY variables
for currently all other HTTP calls that is made inside kubeadm.
kubeadm upgrade apply now is able to utilize all possible combinations
of version argument, including labels (latest, stable-1.8, ci/latest-1.9)
as well as specific builds (v1.8.0-rc.1, ci/v1.9.0-alpha.1.123_01234567889)
As side effect, specifying exact build to deploy from CI area is now also
possible in kubeadm init command.
Fixes: kubernetes/kubeadm#451
As part of issue kubernetes/kubeadm#292 discussion, it
turned out that for users it is not always obvious that
version specification parameter must be in form "vX.Y.Z".
This patch allows to specify it in form "X.Y.Z" and
converts it internally to normal semantic version which
expected in the rest of the code.
Now, defaults can be pointing to "stable" and users will always get
latest available stable build of Kubernetes via kubeadm.
There is no need anymore to hardcode version string inside kubeadm
binary.
It is also possible to use labels like "latest" or point to exact
branch: "stable-1.4"
