Helm

Helm is a tool that installs and upgrades applications on Kubernetes. A real app on Kubernetes needs many YAML files: Deployments, Services, ConfigMaps, Secrets, Ingress rules. Helm bundles them into a package called a chart, so instead of applying a dozen files by hand you run helm install my-db bitnami/postgresql and get a working database.

A chart is a folder of templates with placeholders, plus a values.yaml file with defaults: how many replicas, which image version, how much memory. You override what you need, for example a bigger disk in production, and Helm fills in the templates and sends the result to the cluster. Each installation is a release with a version history, so helm upgrade moves it forward and helm rollback returns it to an earlier version if something breaks.

Charts are shared through repositories, so popular software, from databases to monitoring stacks, usually ships an official chart. Helm is a graduated project of the Cloud Native Computing Foundation, and it is often driven by GitOps tools like Argo CD or Flux. The common complaint is that templated YAML gets hard to read; alternatives like Kustomize patch plain YAML instead.