3.1.1 Client certificate authentication should not be used for users - Identities

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Kubernetes provides the option to use client certificates for user authentication. However as there is no way to revoke these certificates when a user leaves an organization or loses their credential, they are not suitable for this purpose.

It is not possible to fully disable client certificate use within a cluster as it is used for component to component authentication.


With any authentication mechanism the ability to revoke credentials if they are compromised or no longer required, is a key control. Kubernetes client certificate authentication does not allow for this due to a lack of support for certificate revocation.


External mechanisms for authentication generally require additional software to be deployed.


Configure an identity provider for the OpenShift cluster following the OpenShift documentation. Once an identity provider has been defined, you can use RBAC to define and apply permissions.
After you define an identity provider and create a new cluster-admin user you can reduce the attack surface by removing the default kubeadmin user.

Default Value:

By default, only a kubeadmin user exists on your cluster. To specify an identity provider, you must create a Custom Resource (CR) that describes that identity provider and add it to the cluster.

See Also