Automatic merge from submit-queue. 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>.
kubeadm: Utilize transport defaults from API machinery for http calls inside kubeadm
**What this PR does / why we need it**:
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.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes kubernetes/kubeadm#324
**Special notes for your reviewer**:
Based on discussion in #52788, replacing this patch replacing all calls inside kubeadm that are done via DefaultTransport to explicitly defined and initialized with API machinery defaults Transport and http client.
**Release note**:
```release-note
- kubeadm now supports CIDR notations in NO_PROXY environment variable
```
Automatic merge from submit-queue. 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>.
improve error message for expired tokens
**What this PR does / why we need it**:
When you join a node with a expired tokens, you can get fuzz error messages: `[discovery] Failed to connect to API Server "<cluster-ip>:6443": there is no JWS signed token in the cluster-info ConfigMap. This token id "c33826" is invalid for this cluster, can't connect`, we should improve it.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes [https://github.com/kubernetes/kubeadm/issues/630](https://github.com/kubernetes/kubeadm/issues/630)
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
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.
Automatic merge from submit-queue. 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 typos: remove duplicated word in comments
**What this PR does / why we need it**: Remove the duplicated word `the` in comments
**Which issue this PR fixes** : fixes #
**Special notes for your reviewer**:
```release-note
NONE
```
This change adds the `--discovery-token-ca-cert-hash` and `--discovery-token-unsafe-skip-ca-verification` flags for `kubeadm join` and corresponding fields on the kubeadm NodeConfiguration struct. These flags configure enhanced TLS validation for token-based discovery.
The enhanced TLS validation works by pinning the public key hashes of the cluster CA. This is done by connecting to the `cluster-info` endpoint initially using an unvalidated/unsafe TLS connection. After the cluster info has been loaded, parsed, and validated with the existing symmetric signature/MAC scheme, the root CA is validated against the pinned public key set. A second request is made using validated/safe TLS using the newly-known CA and the result is validated to make sure the same `cluster-info` was returned from both requests.
This validation prevents a class of attacks where a leaked bootstrap token (such as from a compromised worker node) allows an attacker to impersonate the API server.
This change also update `kubeadm init` to print the correct `--discovery-token-ca-cert-hash` flag in the example `kubeadm join` command it prints at the end of initialization.
- Factor out token constants to kubeadmconstants.
- Move cmd/kubeadm/app/util/{,token/}tokens.go
- Use the token-id, token-secret, etc constants provided by the bootstrapapi package
- Move cmd/kubeadm/app/master/tokens.go to cmd/kubeadm/app/phases/token/csv.go
This refactor basically makes it possible to hook up kubeadm to the BootstrapSigner controller later on
Automatic merge from submit-queue
Implemented file and HTTPS based discovery for kubeadm
**What this PR does / why we need it**:
This PR implements both file and HTTPS based discovery for `kubeadm`.
**Which issue this PR fixes**:
fixes https://github.com/kubernetes/kubeadm/issues/93
fixes https://github.com/kubernetes/kubeadm/issues/94
**Special notes for your reviewer**:
I'd like to add some tests but 'm sure `kubeconfig` loading is already covered by other tests in `clientcmd` package.
/cc @luxas @pipejakob
