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apply template (#9850)

pull/9852/head
makocchi 2018-08-14 21:54:26 +09:00 committed by k8s-ci-robot
parent 81cdab6cd9
commit 84124958c2
1 changed files with 15 additions and 6 deletions
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content/en/docs/reference/command-line-tools-reference/kubelet-tls-bootstrapping.md
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@ -4,16 +4,19 @@ reviewers:
- mikedanese - mikedanese
- jcbsmpsn - jcbsmpsn
title: TLS bootstrapping title: TLS bootstrapping
content_template: templates/concept
--- ---
{{< toc >}} {{% capture overview %}}
## Overview
This document describes how to set up TLS client certificate bootstrapping for kubelets. This document describes how to set up TLS client certificate bootstrapping for kubelets.
Kubernetes 1.4 introduced an API for requesting certificates from a cluster-level Certificate Authority (CA). The original intent of this API is to enable provisioning of TLS client certificates for kubelets. The proposal can be found [here](https://github.com/kubernetes/kubernetes/pull/20439) Kubernetes 1.4 introduced an API for requesting certificates from a cluster-level Certificate Authority (CA). The original intent of this API is to enable provisioning of TLS client certificates for kubelets. The proposal can be found [here](https://github.com/kubernetes/kubernetes/pull/20439)
and progress on the feature is being tracked as [feature #43](https://github.com/kubernetes/features/issues/43). and progress on the feature is being tracked as [feature #43](https://github.com/kubernetes/features/issues/43).
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## kube-apiserver configuration ## kube-apiserver configuration
The API server should be configured with an [authenticator](/docs/reference/access-authn-authz/authentication/) that can authenticate tokens as a user in the `system:bootstrappers` group. The API server should be configured with an [authenticator](/docs/reference/access-authn-authz/authentication/) that can authenticate tokens as a user in the `system:bootstrappers` group.
@ -24,16 +27,18 @@ controller. As this feature matures, you should ensure tokens are bound to a Rol
While any authentication strategy can be used for the kubelet's initial bootstrap credentials, the following two authenticators are recommended for ease of provisioning. While any authentication strategy can be used for the kubelet's initial bootstrap credentials, the following two authenticators are recommended for ease of provisioning.
1. [Bootstrap Tokens](/docs/reference/access-authn-authz/bootstrap-tokens/) - __alpha__ 1. [Bootstrap Tokens](/docs/reference/access-authn-authz/bootstrap-tokens/) - __beta__
2. [Token authentication file](#token-authentication-file) 2. [Token authentication file](#token-authentication-file)
Using bootstrap tokens is currently __alpha__ and will simplify the management of bootstrap token management especially in a HA scenario. Using bootstrap tokens is currently __beta__ and will simplify the management of bootstrap token management especially in a HA scenario.
### Token authentication file ### Token authentication file
Tokens are arbitrary but should represent at least 128 bits of entropy derived from a secure random number Tokens are arbitrary but should represent at least 128 bits of entropy derived from a secure random number
generator (such as /dev/urandom on most modern systems). There are multiple ways you can generate a token. For example: generator (such as /dev/urandom on most modern systems). There are multiple ways you can generate a token. For example:
`head -c 16 /dev/urandom | od -An -t x | tr -d ' '` ```
head -c 16 /dev/urandom | od -An -t x | tr -d ' '
```
will generate tokens that look like `02b50b05283e98dd0fd71db496ef01e8` will generate tokens that look like `02b50b05283e98dd0fd71db496ef01e8`
@ -194,11 +199,13 @@ kubectl config set-credentials kubelet-bootstrap --token=${BOOTSTRAP_TOKEN} --ku
When starting the kubelet, if the file specified by `--kubeconfig` does not exist, the bootstrap kubeconfig is used to request a client certificate from the API server. On approval of the certificate request and receipt back by the kubelet, a kubeconfig file referencing the generated key and obtained certificate is written to the path specified by `--kubeconfig`. The certificate and key file will be placed in the directory specified by `--cert-dir`. When starting the kubelet, if the file specified by `--kubeconfig` does not exist, the bootstrap kubeconfig is used to request a client certificate from the API server. On approval of the certificate request and receipt back by the kubelet, a kubeconfig file referencing the generated key and obtained certificate is written to the path specified by `--kubeconfig`. The certificate and key file will be placed in the directory specified by `--cert-dir`.
{{< note >}}
**Note:** The following flags are required to enable this bootstrapping when starting the kubelet: **Note:** The following flags are required to enable this bootstrapping when starting the kubelet:
``` ```
--bootstrap-kubeconfig="/path/to/bootstrap/kubeconfig" --bootstrap-kubeconfig="/path/to/bootstrap/kubeconfig"
``` ```
{{< /note >}}
Additionally, in 1.7 the kubelet implements __alpha__ features for enabling rotation of both its client and/or serving certs. Additionally, in 1.7 the kubelet implements __alpha__ features for enabling rotation of both its client and/or serving certs.
These can be enabled through the respective `RotateKubeletClientCertificate` and `RotateKubeletServerCertificate` feature These can be enabled through the respective `RotateKubeletClientCertificate` and `RotateKubeletServerCertificate` feature
@ -220,3 +227,5 @@ approval controller, but for the alpha version of the API it can be done manuall
An administrator can list CSRs with `kubectl get csr` and describe one in detail with `kubectl describe csr <name>`. Before the 1.6 release there were An administrator can list CSRs with `kubectl get csr` and describe one in detail with `kubectl describe csr <name>`. Before the 1.6 release there were
[no direct approve/deny commands](https://github.com/kubernetes/kubernetes/issues/30163) so an approver had to update [no direct approve/deny commands](https://github.com/kubernetes/kubernetes/issues/30163) so an approver had to update
the Status field directly ([rough how-to](https://github.com/gtank/csrctl)). Later versions of Kubernetes offer `kubectl certificate approve <name>` and `kubectl certificate deny <name>` commands. the Status field directly ([rough how-to](https://github.com/gtank/csrctl)). Later versions of Kubernetes offer `kubectl certificate approve <name>` and `kubectl certificate deny <name>` commands.
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