10fd3a0bb8
Add front-proxy-client and front-proxy-ca certificates to the list. Closes-bug: 2019959 Signed-off-by: Elisamara Aoki Goncalves <elisamaraaoki.goncalves@windriver.com> Change-Id: Ie940da7352e80322c9d462c7cc219ceec879597d
143 lines
5.2 KiB
ReStructuredText
143 lines
5.2 KiB
ReStructuredText
.. _kubernetes-certificates-f4196d7cae9c:
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=======================
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Kubernetes Certificates
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=======================
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For Kubernetes, HTTPS is always enabled for both internal and external
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endpoints.
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Kubernetes automatically creates all of its client and server certificates, and
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signs them with a Kubernetes Root |CA|. This includes the server certificate
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for the external ``kube-apiserver`` API endpoint. By default, the Kubernetes
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Root |CA| is automatically generated at install time.
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If desired, you can externally generate a Root |CA| certificate and key, and
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configure it as the Kubernetes Root |CA| during installation. Currently,
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StarlingX supports only Internal |CA| mode with Kubernetes, which only supports
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a Root |CA| for the Kubernetes Root |CA|, not an Intermediate |CA|.
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The public certificate of the Kubernetes Root |CA|, whether auto-generated or
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specified, needs to be configured as a trusted |CA| by external servers
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connecting to |prod|'s Kubernetes API endpoint (e.g. via a remotely installed
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``kubectl`` client).
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.. note::
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Some platform services (sysinv, cert-mon and VIM for example) also use X509
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certificates to access Kubernetes by HTTPS.
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It is optional that you update the Kubernetes Root |CA| with a custom Root CA
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certificate and key, generated by yourself, and trusted by your external
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servers connecting to |prod|’s Kubernetes API endpoint. The |prod|’s Kubernetes
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Root |CA| certificate and key are configured as part of the bootstrap during
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installation.
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.. note::
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You must use a Root |CA| certificate; Intermediate |CA| certificates
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are not supported by upstream Kubernetes.
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Kubernetes certificates include:
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- Kubernetes Root |CA| Certificate
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- Cluster admin client certificate used by ``kubectl``
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- ``kube-controller-manager`` client certificate
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- ``kube-scheduler`` client certificate
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- ``kube-apiserver`` server certificate
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- ``kube-apiserver``'s kubelet client certificate
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- ``kubelet`` client certificate
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**Kubernetes Root CA Certificate**
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The Kubernetes Root |CA| certificate signs all the other Kubernetes
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certificates. This is also the |CA| certificate various components use to
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verify server and client certificates signed by the Kubernetes Root |CA|
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certificate. For example, applications running in pods use Kubernetes Root |CA|
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certificate embedded in service account token to verify the ``kube-apiserver``'s
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server certificate when it makes calls to the kube-apiserver.
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Kubernetes Root |CA| certificate and corresponding private key are stored in
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file system:
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- ``/etc/kubernetes/pki/ca.crt``
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- ``/etc/kubernetes/pki/ca.key``
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.. note::
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Kubernetes Root |CA| certificate is also embedded in various
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configuration files and service account token.
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**Cluster admin client certificate used by kubectl**
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This is the client certificate signed by Kubernetes Root |CA| and embedded in
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``/etc/kubernetes/admin.conf``. It is used by kubectl command to identify
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itself to the ``kube-apiserver``.
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**kube-controller-manager client certificate**
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This is the client certificate signed by Kubernetes Root |CA| and embedded in
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``/etc/kubernetes/controller-manager.conf``. It is used by
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``kube-controller-manager`` pod to identify itself to ``kube-apiserver``.
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**kube-scheduler client certificate**
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This is the client certificate signed by Kubernetes Root |CA| and embedded in
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``/etc/kubernetes/scheduler.conf``. It is used by ``kube-scheduler`` pod to
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identify itself to the ``kube-apiserver``.
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**kube-apiserver server certificate**
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This is the kube-apiserver's serving certificate. Clients connecting to the
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``kube-apiserver`` will verify this certificate using Kubernetes Root |CA|
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certificate. The certificate and the corresponding private key are stored in
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file system:
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- ``/etc/kubernetes/pki/apiserver.crt``
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- ``/etc/kubernetes/pki/apiserver.key``
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**kube-apiserver's kubelet client certificate**
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``kube-apiserver``'s client certificate for communications with ``kubelet``.
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``kube-apiserver`` identifies itself with this certificate when it connects to
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``kubelet``. The certificate and the corresponding private keys are stored in
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file system:
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- ``/etc/kubernetes/pki/apiserver-kubelet-client.crt``
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- ``/etc/kubernetes/pki/apiserver-kubelet-client.key``
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**kubelet client certificate**
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This is the ``kubelet``’s client certificate (with private key in it).
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``kubelet`` identifies itself with this certificate when it connects to
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``kube-apiserver``. ``kubelet`` has Kubernetes Root |CA| certificate in
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``/etc/kubernetes/kubelet.conf`` to verify peer certificates.
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The certificate and its corresponding private key are store in file system as
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one file:
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- ``/var/lib/kubelet/pki/kubelet-client-current.pem``
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This certificate is configured to auto renew.
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**front-proxy-client certificate**
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Client certificates signed by ``front-proxy`` Root |CA| certificate. It is used
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by ``apiserver/aggregator`` to connect to aggregated apiserver(extension
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APIserver).
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**front-proxy-ca certificate**
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The ``front-proxy`` Root |CA| certificate. front-proxy certificates are
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required only if you run ``kube-proxy`` to support an extension API server.
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.. toctree::
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:maxdepth: 1
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update-renew-kubernetes-certificates-52b00bd0bdae
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manual-kubernetes-root-ca-certificate-update-8e9df2cd7fb9
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kubernetes-root-ca-certificate-update-cloud-orchestration-a627f9d02d6d
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