Softwr

Cloud · head to head

Cilium vs Nebula

Cilium logo

Cilium

Cloud

eBPF-based networking, observability and security for Kubernetes

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: Cilium requires a recent Linux kernel, which rules out older distributions and some managed environments; 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: Cilium covers eBPF datapath, Nebula covers Certificate carried identity.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Cilium and Nebula actually diverge.

Attributes where Cilium and Nebula differ
AttributeCiliumNebula
PlatformsKubernetes, LinuxLinux, 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 Cilium

  • eBPF datapath
  • Identity-based policy
  • Hubble observability
  • Sidecar-free mesh

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.

Cilium

  • Kubernetes networking at a scale where iptables-based CNI performance degradesnot Nebula
  • Network policy expressed on workload identity rather than fragile IP rulesnot Nebula
  • Seeing which services actually talk to each other, and what policy is droppingnot Nebula

Nebula

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

Where each one falls short

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

Cilium

  • Requires a recent Linux kernel, which rules out older distributions and some managed environments
  • eBPF is genuinely hard to debug when it misbehaves, and the skill is rare on most teams
  • Broad scope — CNI, policy, mesh, observability — means the learning curve covers several domains at once

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

Cilium

Free
  • CiliumFree
    • 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 Cilium if

  • You need ebpf datapath.
  • You want to start without paying.
  • You work on Kubernetes, Linux.
  • You also want identity-based policy.
Cilium 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 Cilium or Nebula better?
Neither clearly leads. Cilium 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, Cilium or Nebula?
Cilium starts at Free and Nebula at Free.
Does Cilium or Nebula run on more platforms?
Cilium runs on Kubernetes, Linux. Nebula runs on Linux, macOS, Windows, iOS, Android, FreeBSD.
Can I use Cilium for free?
Both have a free tier, so you can try either at no cost before committing.
What is Cilium best used for?
Cilium is most often used for kubernetes networking at a scale where iptables-based cni performance degrades, network policy expressed on workload identity rather than fragile ip rules, seeing which services actually talk to each other, and what policy is dropping. Of those, kubernetes networking at a scale where iptables-based cni performance degrades and network policy expressed on workload identity rather than fragile ip rules are not what Nebula is typically brought in for.
What can Cilium do that Nebula cannot?
Cilium covers eBPF datapath, Identity-based policy, Hubble observability, Sidecar-free mesh. Nebula covers Certificate carried identity, Group based host firewall, Lighthouse discovery, Noise protocol encryption.

Answered from the vendors’ own pages

Cilium: Is Cilium free?

Yes, open source and CNCF-graduated. Isovalent sells an enterprise distribution and support.

Nebula: Does it use WireGuard?

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

Cilium: What does eBPF change?

It lets Cilium run packet-processing programs inside the kernel instead of relying on iptables rule chains, which behave poorly as the number of services grows.

Nebula: Can I run it without Defined Networking?

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

Cilium: Does Cilium replace a service mesh?

It can cover much of what a mesh does without sidecars, though full mesh feature sets still favour Istio or Linkerd.

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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