KLCP flashcards
KLCP · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Pod
- The smallest deployable Kubernetes unit, containing one or more containers that share a network namespace and can share volumes.
- Deployment
- A controller that manages ReplicaSets to provide declarative rolling updates and rollbacks for stateless Pods.
- Service
- An abstraction that exposes a set of Pods via a stable virtual IP and DNS name, with types ClusterIP, NodePort, LoadBalancer, and ExternalName.
- Namespace
- A virtual cluster partition that scopes names for resources; most objects are namespaced, while Nodes and PersistentVolumes are cluster-scoped.
- ConfigMap
- An API object storing non-confidential key/value configuration, consumable as environment variables or mounted volume files.
- Secret
- An API object for sensitive data such as passwords or tokens; values are base64-encoded and not encrypted at rest unless encryption is configured.
- kubectl apply
- A declarative command that creates or updates resources from manifests and records the last-applied configuration for three-way merges.
- Label selector
- A query over key/value labels used by controllers and Services to identify a subset of resources, supporting equality and set-based expressions.
- Taint and toleration
- A node taint repels Pods unless the Pod declares a matching toleration, which permits but does not guarantee scheduling onto that node.
- Readiness probe
- A probe that determines whether a container can receive traffic; failing readiness removes the Pod from Service endpoints without restarting it.
- Liveness probe
- A probe that checks container health; repeated failures cause the kubelet to restart the container according to its restart policy.
- Horizontal Pod Autoscaler
- A controller that adjusts the replica count of a workload based on observed metrics such as CPU utilization or custom metrics.
- StatefulSet
- A workload controller providing stable network identities, ordered deployment and scaling, and persistent storage per replica for stateful applications.
- DaemonSet
- A controller that ensures a copy of a Pod runs on every eligible node, commonly used for log shippers, agents, and node-level services.
- PersistentVolumeClaim
- A namespaced request for storage that binds to a matching PersistentVolume or triggers dynamic provisioning via a StorageClass.
- PodDisruptionBudget
- A policy object limiting voluntary disruptions by specifying minAvailable or maxUnavailable for a selected set of Pods.
- NetworkPolicy
- A namespaced resource that defines allowed ingress and egress traffic for selected Pods; policies are additive and require a supporting CNI plugin.
- Node affinity
- A scheduling rule that constrains which nodes a Pod may run on based on node labels, supporting required and preferred constraints.
- Helm chart
- A package of templated Kubernetes manifests plus default values, installable and upgradable as a named release.
- Kustomize overlay
- A directory of patches and resource references that customizes a shared base manifest set without templating, applied with kubectl apply -k.
- Canary release
- A deployment strategy that routes a small percentage of traffic to a new version and gradually increases it while monitoring health.
- Blue-green deployment
- A strategy running two identical environments where traffic switches from the old (blue) to the new (green) version after validation.
- Ingress
- An API object defining HTTP and HTTPS routing rules to Services; an Ingress controller implements the rules and provisions load balancing.
- Service mesh
- An infrastructure layer providing mutual TLS, traffic splitting, retries, and telemetry for service-to-service communication, often via sidecars.
- GitOps
- An operational model where a Git repository stores the desired cluster state and an automated controller reconciles the cluster to match it.
- Image digest
- A content-addressed SHA identifier for a container image that is immutable, unlike tags which can be reassigned.
- Twelve-Factor App
- A methodology for cloud-native services emphasizing environment-based config, stateless processes, disposability, and logs as event streams.
- Sidecar pattern
- A design where a helper container runs alongside the main container in a Pod to provide cross-cutting features like proxying or logging.
- Operator pattern
- An architecture using custom controllers and CustomResourceDefinitions to encode domain-specific operational knowledge for an application.
- Circuit breaker
- A resilience pattern that stops calls to a failing dependency after a threshold, allowing recovery and preventing cascading failures.
- Observability
- The ability to infer internal system state from external outputs, typically metrics, logs, and distributed traces.
- Loose coupling
- An architectural principle where components interact through well-defined interfaces or asynchronous messaging, minimizing shared dependencies.