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Docker vs Keycloak

Docker logo

Docker

Software

Accelerate how you build, share, and run applications

From
Free
Rated
-
Full reviewWebsite
Keycloak logo

Keycloak

Software

Open-source identity and access management server.

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Docker shared kernel creates security vulnerabilities when containers share the same OS kernel that can bypass container isolation; Keycloak requires self-hosted deployment and operational expertise to install, configure and maintain

Where they differ

Only the attributes on which Docker and Keycloak actually diverge.

Attributes where Docker and Keycloak differ
AttributeDockerKeycloak
Pricing modelUnknownopen-source
PlatformsLinux, macOS, WindowsSelf-hosted, Docker, Kubernetes, Linux, Windows, API
Founded2010Unknown

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Unknown).

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 Docker

  • Container runtime
  • Docker Desktop
  • Docker Hub
  • Docker Compose
  • Container images
  • Dockerfile
  • Docker Swarm
  • BuildKit

Only in Keycloak

Nothing recorded that Docker does not also cover.

What people use each for

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

Docker

  • Application containerizationnot Keycloak
  • Microservicesnot Keycloak
  • CI/CD pipelinesnot Keycloak
  • Development environmentsnot Keycloak
  • Cloud migrationnot Keycloak

Keycloak

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

Where each one falls short

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

Docker

  • Shared kernel creates security vulnerabilities when containers share the same OS kernel that can bypass container isolation
  • Daemon socket exposure grants full root access to the host if compromised
  • Requires careful secrets management - credentials embedded in images or environment variables are easily harvested by attackers
  • Resource management complexity - misbehaving or compromised containers can consume all resources causing denial of service
  • Orchestration complexity - Docker Swarm is less capable than Kubernetes, requiring external tools for production deployments

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

Pricing, plan by plan

Docker

Free

No published plan breakdown. See the Docker review.

Keycloak

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

Which should you pick?

Choose Docker if

  • You need container runtime.
  • You want to start without paying.
  • You work on Linux, macOS, Windows.
  • You also want docker desktop.
Docker review

Choose Keycloak if

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

Questions people ask

Is Docker or Keycloak better?
Neither clearly leads. Docker starts at Free and Keycloak at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Docker or Keycloak?
Docker starts at Free and Keycloak at Free.
Does Docker or Keycloak run on more platforms?
Docker runs on Linux, macOS, Windows. Keycloak runs on Self-hosted, Docker, Kubernetes, Linux, Windows, API.
Can I use Docker for free?
Both have a free tier, so you can try either at no cost before committing.
What is Docker best used for?
Docker is most often used for application containerization, microservices, ci/cd pipelines, development environments. Of those, application containerization and microservices are not what Keycloak is typically brought in for.
What can Docker do that Keycloak cannot?
Docker covers Container runtime, Docker Desktop, Docker Hub, Docker Compose.

Answered from the vendors’ own pages

Docker: What is Docker pricing?

Docker offers a freemium model with Docker Personal free, Docker Pro at $11/user/month, Docker Team at $16/user/month, and Docker Business at $24/user/month. Each tier includes Docker Desktop, Docker Hub, and Docker Scout with different usage limits.

Source
Keycloak: What protocols does Keycloak support?

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

Source
Docker: Can I use Docker in production?

Yes. Docker is used extensively in production environments. However, for container orchestration at scale, Kubernetes is typically paired with Docker to automate deployment, scaling, and management across clusters.

Source
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
Docker: What are the main security concerns with Docker?

Key security risks include container breakout vulnerabilities through shared kernel exploits, daemon socket exposure that grants root access if compromised, weak isolation between containers, and credential leakage if secrets are embedded in images.

Source
Keycloak: Is Keycloak free?

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

Source
Docker: Does Docker integrate with CI/CD systems?

Yes. Docker integrates with Jenkins, GitHub, and other CI/CD systems. The typical workflow involves GitHub repositories triggering automated builds in Jenkins, which prepare Dockerfiles and push images to Docker Hub for deployment.

Source
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