0d7a6eb058
This adds a new stand-alone certificates controller for use on GKE. It allows calling GKE to sign certificates instead of requiring the CA private key locally. It does not aim for 100% feature parity with kube-controller-manager yet, so for instance, leader election support is omitted.
91 lines
2.7 KiB
Go
91 lines
2.7 KiB
Go
/*
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Copyright 2017 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package app
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import (
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"fmt"
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"time"
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"github.com/golang/glog"
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"k8s.io/apimachinery/pkg/runtime/schema"
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"k8s.io/apiserver/pkg/util/webhook"
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"k8s.io/client-go/rest"
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"k8s.io/kubernetes/pkg/api"
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_ "k8s.io/kubernetes/pkg/apis/certificates/install"
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certificates "k8s.io/kubernetes/pkg/apis/certificates/v1beta1"
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)
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var (
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groupVersions = []schema.GroupVersion{certificates.SchemeGroupVersion}
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)
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// GKESigner uses external calls to GKE in order to sign certificate signing
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// requests.
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type GKESigner struct {
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webhook *webhook.GenericWebhook
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kubeConfigFile string
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retryBackoff time.Duration
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}
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// NewGKESigner will create a new instance of a GKESigner.
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func NewGKESigner(kubeConfigFile string, retryBackoff time.Duration) (*GKESigner, error) {
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webhook, err := webhook.NewGenericWebhook(api.Registry, api.Codecs, kubeConfigFile, groupVersions, retryBackoff)
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if err != nil {
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return nil, err
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}
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return &GKESigner{
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webhook: webhook,
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kubeConfigFile: kubeConfigFile,
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retryBackoff: retryBackoff,
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}, nil
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}
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// Sign will make an external call to GKE order to sign the given
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// *certificates.CertificateSigningRequest, using the GKESigner's
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// kubeConfigFile.
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func (s *GKESigner) Sign(csr *certificates.CertificateSigningRequest) (*certificates.CertificateSigningRequest, error) {
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result := s.webhook.WithExponentialBackoff(func() rest.Result {
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return s.webhook.RestClient.Post().Body(csr).Do()
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})
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if err := result.Error(); err != nil {
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return nil, s.webhookError(csr, err)
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}
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var statusCode int
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if result.StatusCode(&statusCode); statusCode < 200 || statusCode >= 300 {
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return nil, s.webhookError(csr, fmt.Errorf("received unsuccessful response code from webhook: %d", statusCode))
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}
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result_csr := &certificates.CertificateSigningRequest{}
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if err := result.Into(result_csr); err != nil {
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return nil, s.webhookError(result_csr, err)
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}
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// Keep the original CSR intact, and only update fields we expect to change.
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csr.Status.Certificate = result_csr.Status.Certificate
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return csr, nil
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}
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func (s *GKESigner) webhookError(csr *certificates.CertificateSigningRequest, err error) error {
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glog.V(2).Infof("error contacting webhook backend: %s", err)
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return err
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}
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