What is a Helm Chart? Explain its standard directory structure.

A Helm Chart is the packaging format for Kubernetes applications - essentially a collection of templates, default configuration values, metadata, and dependencies that together describe a deployable application. Think of a chart as a blueprint that Helm uses to generate and manage Kubernetes manifests. Charts are versioned, can be shared via repositories, and support environment-specific customizations through values files.

The standard Helm chart directory structure follows a convention that Helm expects:

• Chart.yaml - Metadata about the chart: name, version, description, maintainers, type (application/library), and keywords. This file is required.
• values.yaml - Default configuration values that can be overridden during installation. Contains all configurable parameters with sensible defaults.
• templates/ - Directory containing Kubernetes YAML templates with Go template directives. When Helm renders the chart, it combines templates with values to produce manifests.
• templates/NOTES.txt - Optional post-install notes displayed to users after installation.
• templates/_helpers.tpl - Reusable template partials (named with underscores) for DRY chart definitions.
• charts/ - Directory for dependency charts (subcharts). Can contain .tgz files or unpacked chart directories.
• .helmignore - File patterns to exclude when packaging the chart (similar to .gitignore).
• crds/ - Custom Resource Definition YAML files that install before the chart renders.
• README.md - Documentation explaining chart usage, configuration options, and examples.

A minimal chart requires only Chart.yaml, values.yaml, and a templates/ directory with at least one template. Tools like helm create generate a starter chart with examples of each component.