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Cloud · head to head

Cilium vs Linkerd

Cilium logo

Cilium

Cloud

eBPF-based networking, observability and security for Kubernetes

From
Free
Rated
-
Full reviewWebsite
Linkerd logo

Linkerd

Cloud

Lightweight service mesh for Kubernetes

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; Linkerd deliberately fewer features than Istio, so complex routing and multi-cluster policy can hit its limits
  • They diverge on capability: Cilium covers eBPF datapath, Linkerd covers Automatic mutual TLS.

Where they differ

Only the attributes on which Cilium and Linkerd actually diverge.

Attributes where Cilium and Linkerd differ
AttributeCiliumLinkerd

Identical on both: starting price (Free), pricing model (Open source, no licence fee), free tier (Yes), platforms (Kubernetes, Linux), 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 Cilium

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

Only in Linkerd

  • Automatic mutual TLS
  • Golden metrics
  • Rust micro-proxy
  • Traffic policy

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 Linkerd
  • Network policy expressed on workload identity rather than fragile IP rulesnot Linkerd
  • Seeing which services actually talk to each other, and what policy is droppingnot Linkerd

Linkerd

  • Adding mutual TLS between services to satisfy a compliance requirementnot Cilium
  • Getting per-service latency and success rates without instrumenting applicationsnot Cilium
  • Progressive delivery with traffic splitting during rolloutsnot 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

Linkerd

  • Deliberately fewer features than Istio, so complex routing and multi-cluster policy can hit its limits
  • Kubernetes only, with no story for workloads outside a cluster
  • A sidecar per pod is still real memory and latency overhead, however small, and a mesh is another layer to debug during incidents

Pricing, plan by plan

Cilium

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

Linkerd

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

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 Linkerd if

  • You need automatic mutual tls.
  • You want to start without paying.
  • You work on Kubernetes, Linux.
  • You also want golden metrics.
Linkerd review

Questions people ask

Is Cilium or Linkerd better?
Neither clearly leads. Cilium starts at Free and Linkerd at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Cilium or Linkerd?
Cilium starts at Free and Linkerd at Free.
Does Cilium or Linkerd run on more platforms?
Both run on Kubernetes, Linux, so platform support will not decide this one for you.
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 Linkerd is typically brought in for.
What can Cilium do that Linkerd cannot?
Cilium covers eBPF datapath, Identity-based policy, Hubble observability, Sidecar-free mesh. Linkerd covers Automatic mutual TLS, Golden metrics, Rust micro-proxy, Traffic policy.

Answered from the vendors’ own pages

Cilium: Is Cilium free?

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

Linkerd: Is Linkerd free?

The open-source project is free. Buoyant, its maintainer, sells enterprise distributions and support separately.

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.

Linkerd: Linkerd or Istio?

Linkerd trades features for simplicity, with a smaller proxy and far less configuration. Istio is more capable and correspondingly more work to run.

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.

Linkerd: Do I need a service mesh at all?

Only if you need mutual TLS, uniform retries or per-service traffic metrics across many services. For a handful of services it is usually more machinery than the problem justifies.

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