> For the complete documentation index, see [llms.txt](https://dinush-chathurya.gitbook.io/kustomize-e-book/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dinush-chathurya.gitbook.io/kustomize-e-book/additional-topics/17-cli-tools-for-kustomize.md). # CLI Tools for Kustomize The Kustomize CLI and its ecosystem of plugins and helper tools are essential for building, validating, and automating your Kubernetes manifests. In this chapter, we’ll explore the most important commands, plugins, and tips to streamline your Kustomize workflows. *** ## 1. `kubectl kustomize` vs `kustomize build` | Command | Description | | ------------------------- | ----------------------------------------------------------------------------- | | `kubectl kustomize ` | Built-in since Kubernetes v1.14; renders manifests without a separate binary. | | `kustomize build ` | The standalone Kustomize binary; supports the latest features and plugins. | **Tip:** Use `kubectl kustomize` for quick local tests; use `kustomize build` in CI to ensure feature parity and plugin support. *** ## 2. Core CLI Commands * **`kustomize build [dir]`**\ Render all resources in the directory. * **`kustomize edit set image OLD=NEW`**\ Update image references in your `kustomization.yaml`. * **`kustomize cfg`** subcommands * `kustomize cfg check` — validate your resource configurations. * `kustomize cfg fmt` — format your Kustomize files. * `kustomize cfg test` — run YAML-based tests. * **`kustomize version`**\ Shows the client version; important for reproducibility. *** ## 3. Plugin Ecosystem Kustomize supports three plugin types—**Generators**, **Transformers**, and **Executables**—to extend functionality: ```plaintext ~/.config/kustomize/plugin/ ├── yourdomain.com/ │ ├── generators/ │ │ └── mygen/ │ │ └── mygen.go │ └── transformers/ │ └── mytrans/ │ └── mytrans.go ``` * **Generators** produce resources (e.g., CRDs). * **Transformers** modify existing resources (e.g., add labels). * **Exec Plugins** invoke arbitrary executables to generate or transform. Tip: Vendor plugins alongside your repo and pin Kustomize versions to avoid incompatibility. ## 4. Linting & Validation ### kustomize doctor \[dir] Diagnose issues in your Kustomize configuration (e.g., missing resources). ### kubeval / kube-linter Validate rendered YAML against Kubernetes schemas and best practices: ```bash kustomize build overlays/prod | kubeval --strict kustomize build overlays/prod | kube-linter lint - ``` ### Open Policy Agent (OPA) + Conftest Write Rego policies to enforce security or compliance rules on generated manifests: ```bash kustomize build overlays/prod | conftest test - ``` *** ## 5. Scripting & Automation Tips ### Makefiles ```makefile build-dev: kustomize build overlays/dev > deploy/dev.yaml deploy-dev: kubectl apply -f deploy/dev.yaml ``` ### Shell Scripts Wrap multi-step commands: ```bash #!/usr/bin/env bash set -e kustomize build overlays/$1 | kubectl apply -f - ``` ### CI Caching Cache the `$HOME/.config/kustomize/plugin` directory and Docker images generated by plugins. *** ## 6. Version Management ### Homebrew / apt / yum packages for the standalone binary. ### GitHub Releases: Pin to a specific release tag: ```bash curl -s "https://api.github.com/repos/kubernetes-sigs/kustomize/releases/latest" | jq -r '.assets[] | select(.name|test("linux_amd64")) | .browser_download_url' | xargs curl -L -o kustomize chmod +x kustomize && mv kustomize /usr/local/bin/ ``` ### Docker Image: ```bash docker run --rm sigs.k8s.io/kustomize/kustomize:v4.5.7 build overlays/dev ``` *** ## 7. Performance & Scaling * `--load-restrictor=none` when loading remote bases (use with caution). * Limit resources in large repos by splitting into “apps of apps.” * Parallelize builds with GNU parallel or CI matrix jobs. *** ## 8. Best Practices * Pin CLI versions in CI to avoid surprises. * Vendor plugins and test them in isolated environments. * Integrate linters and policy checks early in your pipeline. * Document your Makefile or scripts in the repo’s `README.md`. * Use `kubectl diff` (`kubectl apply --server-dry-run`) to preview changes before applying. *** ## Summary Mastering the Kustomize CLI and its ecosystem of plugins and tools enables you to build robust, automated pipelines that handle complex configurations at scale. By leveraging validation, scripting, and best practices, you’ll ensure reliable, reproducible, and secure Kubernetes deployments. --- # Agent Instructions This documentation is published with GitBook. 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