Last modified August 20, 2026
GitOps tooling reference
This page lists the tools for building and validating Flux manifests, with the command to invoke each one and where it comes from. For guidance on which tool to reach for when something breaks, see tools for your GitOps workflow.
Local build and validation
These tools run against files in your GitOps repository. They don’t need cluster access.
| Tool | Command | What it does | Source |
|---|---|---|---|
fake-flux | fake-flux usage | Mimics the flux CLI locally, generating resources with patches applied and variables filled in. Uses flux build kustomization by default, or kustomize build with --use-kustomize. | giantswarm/gitops-template |
test-all-ff | test-all-ff validate | Finds all Flux kustomization files from the repository root, builds the manifests with fake-flux, then checks them with yamllint and kubeconform. Works in a GitHub action, locally, or as a git pre-commit hook. | giantswarm/gitops-template |
validate.sh | ./validate.sh | Like test-all-ff, but skips yamllint and checks manifests against the OpenAPI Specification with kubeconform. Not a Giant Swarm tool. | fluxcd/flux2-kustomize-helm-example |
flux build kustomization | flux build kustomization <name> --dry-run | Builds a kustomization the way Flux would. In dry-run mode, secret and configmap variables aren’t substituted, so the output is close to but not identical with what Flux applies. | Flux CLI |
kustomize build | kustomize build <dir> | envsubst | Builds a kustomization without substituting variables. Export them and pipe through envsubst yourself. Prints encrypted secrets in full, where flux build shows only the encryption type. Useful for checking that every secret is encrypted and for comparing key fingerprints. | Kustomize |
Cluster inspection
These commands query a cluster. They don’t work against local files.
| Tool | Command | What it does | Source |
|---|---|---|---|
flux tree | flux tree kustomization <name> | Prints a tree of the resources a kustomization manages, organized by sub-kustomization and type. | Flux CLI |
flux trace | flux trace <kind> <name> | Reports which kustomization controls a given resource, and the source revision it came from. Use it to find duplicated resources that two kustomizations are fighting over, and to check whether a resource carries the latest changes. | Flux CLI |
Need help, got feedback?
We listen to your Slack support channel. You can also reach us at support@giantswarm.io. And of course, we welcome your pull requests!