☁️ Free practice test question from: KCNA (KCNA)

Database Service (Critical Financial Transactions):

• Needs: Highest availability, stable performance, guaranteed resources. Cannot tolerate being terminated or having resources throttled unexpectedly.

• Appropriate QoS: Guaranteed. This class is assigned when pods have specific requests and limits set for both CPU and memory, and they are equal. Kubernetes gives these pods the highest priority and avoids evicting them unless absolutely necessary (e.g., node failure) or they exceed their limits.

API Gateway (Unpredictable Traffic, Minimum Performance):

• Needs: Must meet minimum performance levels, but traffic is variable. It needs some guaranteed resources but could potentially benefit from using more resources during traffic spikes if available.

• Appropriate QoS: Burstable. This class is assigned when pods have resource requests specified, but the limits are higher (or limits are set for only one resource type, not both). These pods get the requested resources guaranteed but can "burst" to use more resources up to their limits if available on the node. They have medium eviction priority. This fits the need for minimum performance guarantees with the ability to handle variable load.

Log Collection Service (Temporarily Interruptible):

• Needs: Lowest priority. Functionality is not core to the application's main purpose, and interruptions are acceptable. It should use resources only when they are available and not impact critical services.

• Appropriate QoS: BestEffort. This class is assigned when pods have no resource requests or limits specified. These pods have the lowest priority and are the first to be evicted if the node runs out of resources. They run using leftover resources on the node.