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Cloud · head to head

Kustomize vs Terragrunt

Kustomize logo

Kustomize

Cloud

Template-free customisation of Kubernetes YAML

From
Free
Rated
-
Full reviewWebsite
Terragrunt logo

Terragrunt

Cloud

The Open Source IaC Orchestrator Platform Teams Trust

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Kustomize no packaging or distribution story, which is exactly what Helm charts provide; Terragrunt additional complexity layer on top of Terraform
  • They diverge on capability: Kustomize covers Overlay patching, Terragrunt covers Infrastructure orchestration.

Where they differ

Only the attributes on which Kustomize and Terragrunt actually diverge.

Attributes where Kustomize and Terragrunt differ
AttributeKustomizeTerragrunt
Pricing modelOpen source, no licence feeUnknown
PlatformsKubernetes, Linux, macOS, WindowsAWS, Azure, GCP

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Cloud).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Kustomize

  • Overlay patching
  • No templating language
  • Built into kubectl
  • Generators

Only in Terragrunt

  • Infrastructure orchestration
  • Run Queue
  • DRY configuration
  • Automated hooks
  • Infrastructure catalog
  • Least-privilege access

What people use each for

The jobs each tool is most often brought in to do.

Kustomize

  • Managing dev, staging and production variants of the same manifestsnot Terragrunt
  • Keeping manifests readable and directly applyable rather than templatednot Terragrunt
  • Patching third-party manifests without forking themnot Terragrunt

Terragrunt

  • Organizing Terraform code across multiple environmentsnot Kustomize
  • Automating infrastructure deployment workflowsnot Kustomize
  • Implementing infrastructure as code templates for developer self-servicenot Kustomize

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Kustomize

  • No packaging or distribution story, which is exactly what Helm charts provide
  • Deeply nested overlays become hard to follow, and reasoning about the final output requires building it
  • No release lifecycle: nothing tracks what is installed or supports rollback the way Helm does
  • Patch syntax is fiddly for anything beyond simple field replacement

Terragrunt

  • Additional complexity layer on top of Terraform
  • Requires understanding of Terraform concepts
  • Paid tier pricing not clearly published

Pricing, plan by plan

Kustomize

Free
  • KustomizeFree
    • Full functionality
    • No usage limits
    • Community support

Terragrunt

Free
  • Open SourceFree
    • Terragrunt CLI - completely free
    • Community support
  • Terragrunt Scale FreeFree
    • Free CI/CD pipeline
    • Unlimited runs and resources
    • For up to 25 infrastructure units
  • Terragrunt Scale Paid$undefined/custom
    • Volume pricing for more than 25 infrastructure units
    • Enterprise support

Which should you pick?

Choose Kustomize if

  • You need overlay patching.
  • You want to start without paying.
  • You work on Kubernetes, Linux, macOS, Windows.
  • You also want no templating language.
Kustomize review

Choose Terragrunt if

  • You need infrastructure orchestration.
  • You want to start without paying.
  • You work on AWS, Azure, GCP.
  • You also want run queue.
Terragrunt review

Questions people ask

Is Kustomize or Terragrunt better?
Neither clearly leads. Kustomize starts at Free and Terragrunt at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Kustomize or Terragrunt?
Kustomize starts at Free and Terragrunt at Free.
Does Kustomize or Terragrunt run on more platforms?
Kustomize runs on Kubernetes, Linux, macOS, Windows. Terragrunt runs on AWS, Azure, GCP.
Can I use Kustomize for free?
Both have a free tier, so you can try either at no cost before committing.
What is Kustomize best used for?
Kustomize is most often used for managing dev, staging and production variants of the same manifests, keeping manifests readable and directly applyable rather than templated, patching third-party manifests without forking them. Of those, managing dev, staging and production variants of the same manifests and keeping manifests readable and directly applyable rather than templated are not what Terragrunt is typically brought in for.
What can Kustomize do that Terragrunt cannot?
Kustomize covers Overlay patching, No templating language, Built into kubectl, Generators. Terragrunt covers Infrastructure orchestration, Run Queue, DRY configuration, Automated hooks.

Answered from the vendors’ own pages

Kustomize: Is Kustomize free?

Yes, open source and part of the Kubernetes project.

Terragrunt: Is Terragrunt free?

Yes, the Terragrunt CLI is completely free and open source. Terragrunt Scale offers a free tier for up to 25 infrastructure units.

Source
Kustomize: Kustomize or Helm?

Kustomize patches plain YAML and keeps bases readable; Helm templates and packages applications with a release lifecycle. Many teams use both — Helm to install third-party charts, Kustomize to patch them.

Terragrunt: What is the difference between Terragrunt and Terraform?

Terragrunt is an orchestration layer on top of Terraform that handles state management, DRY principles, and deployment automation without replacing Terraform itself.

Source
Kustomize: Do I need to install Kustomize?

No. It is built into kubectl, available through kubectl apply -k.

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