Softwr

Cloud · head to head

Cilium vs OpenSearch

Cilium logo

Cilium

Cloud

eBPF-based networking, observability and security for Kubernetes

From
Free
Rated
-
Full reviewWebsite
OpenSearch logo

OpenSearch

Databases

Open-source search and analytics suite forked from Elasticsearch

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; OpenSearch diverged from Elasticsearch since 7.10, so clients, plugins and features no longer map one to one
  • They diverge on capability: Cilium covers eBPF datapath, OpenSearch covers Full-text search.
  • Prices and features above were last checked on 29 August 2026.

Where they differ

Only the attributes on which Cilium and OpenSearch actually diverge.

Attributes where Cilium and OpenSearch differ
AttributeCiliumOpenSearch
Pricing modelOpen source, no licence feeOpen source, no licence fee; managed services billed separately
PlatformsKubernetes, LinuxLinux, Docker, Kubernetes, Self-hosted
CategoryCloudDatabases

Identical on both: starting price (Free), 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 OpenSearch

  • Full-text search
  • OpenSearch Dashboards
  • Log analytics
  • Vector search

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

OpenSearch

  • Log and observability storage where an Apache-2.0 licence is a requirementnot Cilium
  • Replacing Elasticsearch after the licence change without changing architecturenot Cilium
  • Search plus analytics on one cluster rather than two systemsnot 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

OpenSearch

  • Diverged from Elasticsearch since 7.10, so clients, plugins and features no longer map one to one
  • Operationally heavy in the way Elasticsearch is: cluster sizing, shard strategy and JVM tuning are ongoing work
  • Smaller ecosystem of third-party tooling than Elasticsearch, which most integrations still target first
  • Overkill for plain application search, where a dedicated search engine is far simpler

Pricing, plan by plan

Cilium

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

OpenSearch

Free
  • OpenSearchFree
    • Full functionality
    • Self-hosted
    • No usage limits

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 OpenSearch if

  • You need full-text search.
  • You want to start without paying.
  • You work on Linux, Docker, Kubernetes, Self-hosted.
  • You also want opensearch dashboards.
OpenSearch review

Questions people ask

Is Cilium or OpenSearch better?
Neither clearly leads. Cilium starts at Free and OpenSearch at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Cilium or OpenSearch?
Cilium starts at Free and OpenSearch at Free.
Does Cilium or OpenSearch run on more platforms?
Cilium runs on Kubernetes, Linux. OpenSearch runs on Linux, Docker, Kubernetes, Self-hosted.
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 OpenSearch is typically brought in for.
What can Cilium do that OpenSearch cannot?
Cilium covers eBPF datapath, Identity-based policy, Hubble observability, Sidecar-free mesh. OpenSearch covers Full-text search, OpenSearch Dashboards, Log analytics, Vector search.

Answered from the vendors’ own pages

Cilium: Is Cilium free?

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

OpenSearch: Is OpenSearch free?

Yes, Apache 2.0 licensed under the Linux Foundation. Amazon OpenSearch Service is a paid managed option.

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.

OpenSearch: Why does OpenSearch exist?

Elastic moved Elasticsearch off the Apache 2.0 licence in 2021. AWS forked the last Apache-licensed version, and the project now sits under the Linux Foundation.

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.

OpenSearch: Is OpenSearch compatible with Elasticsearch?

It was at the 7.10 fork point. Both have developed independently since, so compatibility weakens with every release and should be verified for the features you use.

Share

Related pages

More on Cilium

More on OpenSearch

Keep looking

Other head to heads