Last modified March 17, 2025

Tools for your GitOps workflow

These tools can help you solve issues when deploying resources with Flux. Some are created by Giant Swarm, while others come from Flux or the wider community.

We’ve selected tools that we find most helpful for troubleshooting Flux-controlled resources.

Flux script

Giant Swarm created a script that mimics the flux CLI locally.

This script ensures your resources are correctly generated with patches applied and variables filled in.

Find it in our gitops-template tooling

For help, run fake-flux usage or check the examples in the repository.

Test all with a custom script

This script works best in a GitHub action but can also run locally or in a git pre-commit hook.

It checks all manifests for errors using yamllint and kubeconform. These tools verify manifests built from Flux kustomization paths.

To use it, run test-all-ff validate from your GitOps repository root. The script finds all Flux kustomization files, builds manifests with fake-flux, and checks them with yamllint and kubeconform.

Find this script in our gitops-template tooling.

Flux validation

The validate.sh script works like test-all-ff but uses kubeconform differently. Instead of running yamllint, it checks manifests against the OpenAPI Specification.

This script isn’t from Giant Swarm - find it in the kustomize examples.

Flux build

When other tools don’t help, try flux build kustomization with --dry-run. This is what fake-flux uses by default.

Note that in dry-run mode, secret and configmap variables aren’t replaced. Your manifests won’t exactly match what Flux uses on the server, but they’ll be close enough to spot problems.

Learn more in the Flux documentation.

Kustomize build

Using kustomize build is more complex than flux build kustomization. It doesn’t replace variables automatically. You need to:

1. Export environment variables
2. Build the manifest
3. Use envsubst in a pipe

You can do this with fake-flux using the --use-kustomize flag.

While similar to flux build kustomization, kustomize build shows encrypted secrets differently. Flux shows only the encryption type (like SOPS), while kustomize shows the entire encrypted secret.

This helps you quickly check if all secrets are encrypted and compare key fingerprints.

Find more details in the Kustomize documentation.

flux CLI

The flux CLI has many useful commands. Check their CLI documentation to learn more.

Two commands are especially helpful for checking resources on your cluster:

1. flux tree
2. flux trace

flux tree

flux tree shows resources managed by a kustomization.

This command only works on a cluster, not with local files. It displays a tree of resources organized by sub-kustomization and type.

flux trace

When looking at a cluster resource, it can be hard to know if Flux controls it and which kustomization manages it.

Sometimes resources are duplicated in your repository, causing multiple kustomizations to fight for control. Or you might create a child kustomization while the parent already controls those files.

flux trace helps identify which kustomization controls a resource and shows its source revision, helping you check if it has the latest changes.