Certificates¶
Certificates are a crucial part of Kubernetes’ security infrastructure, serving to authenticate and secure communication within the cluster. They play a key role in ensuring that communication between various components (such as the API server, kubelets, and the datastore) is both encrypted and restricted to authorised components only.
In Kubernetes, X.509 certificates are primarily used for Transport Layer Security (TLS), securing the communication between the cluster’s components.
What Is a Certificate Refresh?¶
A certificate refresh in Canonical Kubernetes refers to the process of renewing or rotating certificates before they expire. Kubernetes certificates have a specific validity period, after which they expire and are no longer considered valid. Expired certificates lead to failures in communication between cluster components, potentially disrupting the functionality of the entire cluster.
Regular certificate refreshes ensure that the certificates in use are valid and secure, preventing unauthorised access or communication failures.
Importance of Certificate Refreshes¶
Regularly refreshing certificates in Kubernetes is essential for maintaining the reliability of the cluster. Here are some reasons why certificate refreshes are important:
Maintaining Cluster Security¶
Certificates are crucial for securing Kubernetes clusters, ensuring encrypted and authenticated communication between components. If a certificate expires and isn’t promptly renewed, it can leave the cluster vulnerable to security risks, potentially exposing it to unauthorised access. Regular certificate refreshes prevent this by ensuring only valid certificates are used, maintaining the cluster’s security.
Preventing Downtime¶
Kubernetes relies on certificates for internal communication between critical components, such as the kubelet, API server, and datastore. Expired certificates can hinder this communication, leading to potential downtime and workload disruptions. Proactively refreshing certificates before they expire helps maintain uninterrupted cluster operations.
Security Compliance¶
Security standards, such as CIS, often require the regular rotation of credentials, including certificates. Periodically renewing Kubernetes certificates ensures that the cluster meets security standards and compliance requirements.