Certified Kubernetes Administrator (CKA) Practice Test

High availability in Kubernetes is crucial for maintaining the reliability and uptime of applications. The correct answer indicates that both stacked etcd and external etcd can be utilized as patterns for achieving high availability.

Stacked etcd refers to a configuration where etcd nodes are deployed on the same machines as the Kubernetes control plane components (like the API server). While this setup is simpler and can function effectively for small-scale deployments or testing environments, it can become a single point of failure if not configured correctly.

On the other hand, external etcd refers to a setup where etcd nodes are deployed separately from the control plane components. This configuration is advantageous for production environments as it allows for better resource allocation, scaling options, and redundancy. It also helps in isolating the storage layer from potential failures in the control plane, enhancing overall availability and resilience.

Using either of these methods contributes to building a high-availability architecture in a Kubernetes cluster. Stacked etcd can work for smaller setups but is often paired with external etcd in larger, production-grade environments to ensure that the etcd service itself remains robust and available. Thus, acknowledging both configurations as valid patterns for high availability reflects an understanding of how Kubernetes can be deployed in resilient architectures.