kapp CLI encourages Kubernetes users to manage resources in bulk by working with "Kubernetes applications" (sets of resources with the same label). It focuses on resource diffing, labeling, deployment and deletion. Unlike tools like Helm, kapp considers YAML templating and management of packages outside of its scope, though it works great with tools that generate Kubernetes configuration.
Features:
Works with standard Kubernetes YAMLs
Focuses exclusively on deployment workflow, not packaging or templating
but plays well with tools (such as ytt) that produce Kubernetes configuration
Converges application resources (creates, updates and/or deletes resources) in each deploy
based on comparison between provided files and live objects in the cluster
Separates calculation of changes (diff stage) from application of changes (apply stage)
Works without admin privileges and does not depend on any custom CRDs
making it possible to use kapp as a regular user in a single namespace
Records application deployment history
Opt-in resource version management
for example, to trigger Deployment rollout when ConfigMap changes
Works with any group of labeled resources (kapp -a label:tier=web inspect -t)