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Developer Tools · head to head

Keycloak vs Longhorn

Keycloak logo

Keycloak

Developer Tools

Open-source identity and access management server.

From
Free
Free plan
Yes
Full reviewWebsite
Longhorn logo

Longhorn

Cloud

Open source distributed block storage for Kubernetes, incubating at the CNCF

From
Free
Free plan
Yes
Full reviewWebsite

The short version

  • Each has a real cost: Keycloak requires self-hosted deployment and operational expertise to install, configure and maintain; Longhorn there is no vendor and no SLA, so a production incident at three in the morning is your own problem unless you buy SUSE Rancher Prime support separately.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Keycloak and Longhorn actually diverge.

Attributes where Keycloak and Longhorn differ
AttributeKeycloakLonghorn
Pricing modelopen-sourceOpen source, no licence fee
PlatformsSelf-hosted, Docker, Kubernetes, Linux, Windows, APILinux, Kubernetes
CategoryDeveloper ToolsCloud

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 Keycloak

Nothing recorded that Longhorn does not also cover.

Only in Longhorn

  • Per-volume controllers
  • Synchronous replication
  • Snapshots and backups
  • Volume expansion
  • Disaster recovery volumes
  • Web interface

What people use each for

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

Keycloak

  • Organisations requiring self-hosted identity infrastructure for compliance or data residencynot Longhorn
  • Companies with existing LDAP/Active Directory systems needing federated authenticationnot Longhorn
  • Open-source projects and communities requiring free IAM without licensing costsnot Longhorn
  • Enterprises building custom identity workflows requiring fine-grained authorisationnot Longhorn
  • Teams with sufficient operational expertise to manage infrastructurenot Longhorn

Longhorn

  • An on-premises Kubernetes cluster with local disks and no SAN that needs replicated persistent volumesnot Keycloak
  • Edge sites where shipping a storage array is impractical and three nodes is the whole clusternot Keycloak
  • A K3s deployment where the storage layer must be light enough to run alongside the workloadsnot Keycloak
  • A team that wants snapshots and S3 backups of persistent volumes without paying per-node storage licencesnot Keycloak

Where each one falls short

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

Keycloak

  • Requires self-hosted deployment and operational expertise to install, configure and maintain
  • No managed cloud option provided by Red Hat; organisations must operate infrastructure themselves or use third-party distributions
  • Clustering and high-availability configurations require additional operational knowledge
  • Community support only; commercial support requires third-party vendors or distributions

Longhorn

  • There is no vendor and no SLA, so a production incident at three in the morning is your own problem unless you buy SUSE Rancher Prime support separately.
  • Synchronous replication across nodes means write latency depends on the slowest replica and the network between nodes, which makes it a poor fit for latency-sensitive databases.
  • Every replica is a full copy, so three-way replication consumes three times the raw capacity, unlike erasure-coded systems that are far more space efficient.
  • It is designed for block storage on modest clusters and does not scale to the node counts or throughput that Ceph or a commercial array handles, so growth eventually forces a migration.
  • Recovery from certain degraded states, such as a volume stuck detaching or replicas failing to rebuild, requires manual intervention and knowledge of Longhorn internals that is not widely held.

Pricing, plan by plan

Keycloak

Free
  • Open-sourceFree
    • Full platform functionality
    • Self-hosted deployment
    • Community support

Longhorn

Free
  • LonghornFree
    • Apache 2.0 licensed, no licence fee
    • Community support via GitHub and Slack only
    • No vendor SLA or escalation path

Which should you pick?

Choose Keycloak if

  • You want to start without paying.
  • You work on Self-hosted, Docker, Kubernetes, Linux, Windows, API.
Keycloak review

Choose Longhorn if

  • You need per-volume controllers.
  • You want to start without paying.
  • You work on Linux, Kubernetes.
  • You also want synchronous replication.
Longhorn review

Questions people ask

Is Keycloak or Longhorn better?
Neither clearly leads. Keycloak starts at Free and Longhorn at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Keycloak or Longhorn?
Keycloak starts at Free and Longhorn at Free.
Does Keycloak or Longhorn run on more platforms?
Keycloak runs on Self-hosted, Docker, Kubernetes, Linux, Windows, API. Longhorn runs on Linux, Kubernetes.
Can I use Keycloak for free?
Both have a free tier, so you can try either at no cost before committing.
What is Keycloak best used for?
Keycloak is most often used for organisations requiring self-hosted identity infrastructure for compliance or data residency, companies with existing ldap/active directory systems needing federated authentication, open-source projects and communities requiring free iam without licensing costs, enterprises building custom identity workflows requiring fine-grained authorisation. Of those, organisations requiring self-hosted identity infrastructure for compliance or data residency and companies with existing ldap/active directory systems needing federated authentication are not what Longhorn is typically brought in for.
What can Keycloak do that Longhorn cannot?
Longhorn covers Per-volume controllers, Synchronous replication, Snapshots and backups, Volume expansion.

Answered from the vendors’ own pages

Keycloak: What protocols does Keycloak support?

Keycloak supports OpenID Connect, OAuth 2.0 and SAML 2.0 protocols for authentication and authorisation.

Source
Longhorn: Who do we call when it breaks?

Nobody, unless you buy SUSE Rancher Prime, which includes commercial support for Longhorn. This is the decisive question for production use.

Keycloak: Can Keycloak integrate with existing user directories?

Yes. Keycloak supports user federation with LDAP and Active Directory systems, allowing organisations to leverage existing user directories.

Source
Longhorn: How much capacity does replication cost?

Full copies, so three replicas means three times the raw capacity. Budget accordingly rather than assuming erasure coding efficiency.

Keycloak: Is Keycloak free?

Yes. Keycloak is fully open-source and free to deploy and use. No licensing fees are required.

Source
Longhorn: Is it suitable for production databases?

For modest workloads yes, but synchronous replication adds write latency and high-transaction databases usually want something faster.

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