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Cloud · head to head

Kustomize vs Nebula

Kustomize logo

Kustomize

Cloud

Template-free customisation of Kubernetes YAML

From
Free
Rated
-
Full reviewWebsite
Nebula logo

Nebula

Networking

Certificate based overlay network from Slack, with identity and firewall rules carried in the certificate

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; Nebula the open source project has no user interface, no enrolment workflow and no revocation service, so certificate issuing, distribution and expiry become scripts you write and then have to keep working.
  • They diverge on capability: Kustomize covers Overlay patching, Nebula covers Certificate carried identity.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Kustomize and Nebula actually diverge.

Attributes where Kustomize and Nebula differ
AttributeKustomizeNebula
PlatformsKubernetes, Linux, macOS, WindowsLinux, macOS, Windows, iOS, Android, FreeBSD
CategoryCloudNetworking

Identical on both: starting price (Free), pricing model (Open source, no licence fee), free tier (Yes), user rating (Not yet rated).

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 Nebula

  • Certificate carried identity
  • Group based host firewall
  • Lighthouse discovery
  • Noise protocol encryption
  • Unsafe routes
  • Managed option

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 Nebula
  • Keeping manifests readable and directly applyable rather than templatednot Nebula
  • Patching third-party manifests without forking themnot Nebula

Nebula

  • Flattening a network across several clouds and datacentres without VPC peering or route tablesnot Kustomize
  • Very large fleets where a central policy service on the connection path is unacceptablenot Kustomize
  • Environments that already run an internal certificate authority and want the network to use itnot Kustomize
  • Replacing per host iptables rules with policy written against roles that follow the hostnot 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

Nebula

  • The open source project has no user interface, no enrolment workflow and no revocation service, so certificate issuing, distribution and expiry become scripts you write and then have to keep working.
  • Revoking a compromised host means distributing a blocklist entry to every other host and reloading them, which is a fleet wide operation rather than a click, and easy to get wrong under pressure.
  • Changing a host group membership means reissuing and redeploying its certificate, so policy changes are a deployment rather than a configuration edit.
  • There is no identity provider integration or single sign on in the open source version, so it maps well to servers and badly to a fleet of user laptops.
  • NAT traversal is best effort and hosts behind symmetric NAT need a relay configured deliberately, so connectivity failures show up as intermittent rather than immediate and are awkward to diagnose.

Pricing, plan by plan

Kustomize

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

Nebula

Free
  • NebulaFree
    • Full functionality under the MIT licence
    • No host limit
    • You operate the certificate authority and lighthouses
  • Defined Networking$undefined/month
    • Hosted control plane and enrolment
    • Managed certificate lifecycle and revocation
    • Policy and DNS interface

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 Nebula if

  • You need certificate carried identity.
  • You want to start without paying.
  • You work on Linux, macOS, Windows, iOS, Android, FreeBSD.
  • You also want group based host firewall.
Nebula review

Questions people ask

Is Kustomize or Nebula better?
Neither clearly leads. Kustomize starts at Free and Nebula at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Kustomize or Nebula?
Kustomize starts at Free and Nebula at Free.
Does Kustomize or Nebula run on more platforms?
Kustomize runs on Kubernetes, Linux, macOS, Windows. Nebula runs on Linux, macOS, Windows, iOS, Android, FreeBSD.
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 Nebula is typically brought in for.
What can Kustomize do that Nebula cannot?
Kustomize covers Overlay patching, No templating language, Built into kubectl, Generators. Nebula covers Certificate carried identity, Group based host firewall, Lighthouse discovery, Noise protocol encryption.

Answered from the vendors’ own pages

Kustomize: Is Kustomize free?

Yes, open source and part of the Kubernetes project.

Nebula: Does it use WireGuard?

No. Nebula predates the common WireGuard mesh tools and uses the Noise protocol framework with its own certificate format.

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.

Nebula: Can I run it without Defined Networking?

Yes, entirely. Defined Networking sells the control plane conveniences, not the network itself.

Kustomize: Do I need to install Kustomize?

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

Nebula: How do I revoke a host?

Add its certificate fingerprint to the blocklist in the configuration of the other hosts and reload them. There is no online revocation check.

Nebula: Is it a good fit for laptops?

Less so than the identity provider based tools. There is no single sign on, so every laptop needs a certificate issued and renewed by whatever process you build.

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