Rotate kubelet server certificate. (#6453)

* Rotate kubelet server certificate.

* CI test kubelet server cert rotation

* Approve kubelet serving certificates in tests.
This commit is contained in:
Lovro Seder 2020-09-03 16:25:41 +02:00 committed by GitHub
parent 2ff7ab8d40
commit c1ba8e1b3a
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6 changed files with 39 additions and 1 deletions

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@ -128,6 +128,11 @@ Stack](https://github.com/kubernetes-sigs/kubespray/blob/master/docs/dns-stack.m
to match Docker configuration.
* *kubelet_rotate_certificates* - Auto rotate the kubelet client certificates by requesting new certificates
from the kube-apiserver when the certificate expiration approaches.
* *kubelet_rotate_server_certificates* - Auto rotate the kubelet server certificates by requesting new certificates
from the kube-apiserver when the certificate expiration approaches.
**Note** that server certificates are **not** approved automatically. Approve them manually
(`kubectl get csr`, `kubectl certificate approve`) or implement custom approving controller like
[kubelet-rubber-stamp](https://github.com/kontena/kubelet-rubber-stamp).
* *node_labels* - Labels applied to nodes via kubelet --node-labels parameter.
For example, labels can be set in the inventory as variables or more widely in group_vars.
*node_labels* can be defined either as a dict or a comma-separated labels string:

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@ -198,7 +198,10 @@ apiServer:
{% endif %}
{% if event_ttl_duration is defined %}
event-ttl: {{ event_ttl_duration }}
{%endif%}
{% endif %}
{% if kubelet_rotate_server_certificates %}
kubelet-certificate-authority: {{ kube_cert_dir }}/ca.crt
{% endif %}
{% if kubernetes_audit or kube_basic_auth|default(true) or kube_token_auth|default(true) or kube_webhook_token_auth|default(false) or ( cloud_provider is defined and cloud_provider in ["openstack", "azure", "vsphere", "aws"] ) or apiserver_extra_volumes or ssl_ca_dirs|length %}
extraVolumes:
{% if cloud_provider is defined and cloud_provider in ["openstack", "azure", "vsphere", "aws"] %}

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@ -34,6 +34,9 @@ clusterDomain: {{ dns_domain }}
{% if kubelet_rotate_certificates|bool %}
rotateCertificates: true
{% endif %}
{% if kubelet_rotate_server_certificates|bool %}
serverTLSBootstrap: true
{% endif %}
{# DNS settings for kubelet #}
{% if enable_nodelocaldns %}
{% set kubelet_cluster_dns = [nodelocaldns_ip] %}

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@ -394,6 +394,8 @@ kubelet_authorization_mode_webhook: true
# kubelet uses certificates for authenticating to the Kubernetes API
# Automatically generate a new key and request a new certificate from the Kubernetes API as the current certificate approaches expiration
kubelet_rotate_certificates: true
# kubelet can also request a new server certificate from the Kubernetes API
kubelet_rotate_server_certificates: false
## List of key=value pairs that describe feature gates for
## the k8s cluster.

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@ -25,6 +25,7 @@ metrics_server_kubelet_insecure_tls: true
kube_token_auth: true
kube_basic_auth: true
enable_nodelocaldns: false
kubelet_rotate_server_certificates: true
kube_oidc_url: https://accounts.google.com/.well-known/openid-configuration
kube_oidc_client_id: kubespray-example

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@ -15,6 +15,30 @@
bin_dir: "/usr/local/bin"
when: not ansible_os_family in ["Flatcar Container Linux by Kinvolk"]
- name: Approve kubelet serving certificates
block:
- name: Get certificate signing requests
command: "{{ bin_dir }}/kubectl get csr -o name"
register: get_csr
changed_when: false
- name: Check there are csrs
assert:
that: get_csr.stdout_lines | length > 0
fail_msg: kubelet_rotate_server_certificates is {{ kubelet_rotate_server_certificates }} but no csr's found
- name: Approve certificates
command: "{{ bin_dir }}/kubectl certificate approve {{ get_csr.stdout_lines | join(' ') }}"
register: certificate_approve
when: get_csr.stdout_lines | length > 0
changed_when: certificate_approve.stdout
- debug:
msg: "{{ certificate_approve.stdout.split('\n') }}"
when: kubelet_rotate_server_certificates | default(false)
- name: Create test namespace # noqa 301 305
shell: "{{ bin_dir }}/kubectl create namespace test"