Kustomizeis a Kubernetes-native configuration management tool that allows manifest customization without modifying the original YAML files. It uses overlays and patches to adapt configurations for different environments.

“Kustomize provides a declarative way to customize Kubernetes manifests by applying patches and overlays. This allows managing multiple environments without duplicating manifest files.”

Thus, the correct answer isD.

In GitOps, thepull-based modelcontinuously reconciles the actual state with the desired state. This makes it resilient to drift, since reconciliation runs regularly. In contrast,event-driven systemsonly reconcile when an event occurs (e.g., a webhook), which makes them more prone to drift if changes happen outside those events.

“A pull-based reconciliation loop ensures continuous alignment with the desired state. Event-driven reconciliation, triggered only on events, risks system drift if changes occur outside those triggers.”

Thus, the correct answer isD.

A fundamental GitOps principle is that reconciliation isautomated and continuous. Software agents (e.g., controllers like ArgoCD or Flux) continuously pull desired state declarations from Git repositories and reconcile them with the actual state.

“Software agents automatically pull the desired state declarations from the source of truth and continuously reconcile the actual state to match.”

Thus, the correct answer isC.

In GitOps, thedesired stateis stored in Git. Manual updates applied directly to the cluster (via kubectl or APIs) change theactual statewithout updating Git. This introducesdriftbetween actual and desired state.

“Manual changes to the runtime environment cause the actual state to diverge from the desired state stored in Git. This drift must be detected and reconciled automatically.”

Thus, the correct answer isC.

Prometheus is commonly used in GitOps for monitoring.Alertmanageris the tool integrated with Prometheus to handle alert routing. It supports sending alerts to external systems such as Slack, PagerDuty, or email.

“Prometheus generates alerts, which are routed and managed by Alertmanager. Alertmanager can integrate with messaging tools like Slack to deliver alerts in real time.”

Thus, the correct answer isA: Alertmanager.

One of the GitOps principles isVersioned and Immutable, which requires that the Desired State is stored in a system that maintains acomplete version history. This allows for auditing, traceability, and rollback.

“The Desired State must be stored in a versioned, immutable system. The State Store must retain a complete version history so changes can be audited and previous states can be restored.”

Thus, the correct answer isB.

Progressive deliveryis a GitOps pattern used to release software gradually, reducing risks associated with deploying new versions. Techniques such as canary releases, feature flags, and blue-green deployments allow teams to incrementally roll out changes, validate functionality with subsets of users, and minimize potential disruptions.

“Progressive delivery builds on continuous delivery by enabling safer, incremental rollouts. This pattern reduces risk, improves reliability, enhances user experience, and allows for validation of features with a portion of users before wider release.”

Therefore, progressive delivery is useful inmultiple scenarios(not just one-time deployments or small teams), making optionCcorrect.