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High availability overview

Explore the different Keycloak high-availability architectures

Keycloak can be deployed in a number of high-availability architectures, allowing system administrators to pick the deployment type most suitable for their needs. Ease of deployment, cost and fault-tolerance guarantees are important considerations when determining the correct architecture for your deployments.

Architectures

This document describes the high availability architectures in which to deploy Keycloak.

Single-cluster deployments

Deploy Keycloak in a single cluster, optionally across multiple availability-zones or data centers with the required network latency and database configuration, using Single-cluster deployments.

Advantages
  • No external dependencies

  • Deployment in a single Kubernetes cluster or a set of virtual machines with transparent networking

  • Tolerate availability-zone failure or data center failure, if deployed to multiple availability zones or data centers

Disadvantages
  • Kubernetes cluster is a single point of failure:

    • Control-plane failures could impact all Keycloak pods

Multi-cluster deployments (v1)

Connect two Keycloak clusters deployed for example in different Kubernetes clusters in two availability zones or data centers with the required network latency and database configuration using Multi-cluster deployments (v1).

Advantages
  • Tolerate availability-zone failure

  • Tolerate Kubernetes cluster failure

  • Bridge two networks that do not offer transparent networking

  • Regulatory compliance when distinct deployments are required

Disadvantages
  • Complexity:

    • External load-balancer required

    • Separate Infinispan cluster required on each site

  • Cost:

    • Additional load-balancer required

    • Additional compute is required for external Infinispan clusters

    • Two Kubernetes control-planes must be provisioned

  • Not supported with three or more availability zones

Multi-cluster deployments (v2)

This section is describing a feature which is currently in preview. Please provide your feedback by joining this discussion while we’re continuing to work on this.

Connect two or more Keycloak clusters without an external Infinispan cluster using Multi-cluster deployments (v2).

Advantages
  • Tolerate availability-zone failure

  • Tolerate cluster failure

  • Simpler architecture: no external Infinispan cluster required

  • No requirement for a specific environment such as Kubernetes or AWS

Disadvantages
  • Complexity:

    • External load-balancer required

  • Cost:

    • Additional load-balancer required

    • Two or more control-planes must be provisioned

    • Higher database load as session data is stored in the database and less data is cached. You might see approximately twice the CPU usage and write IOPS on your database, though your results might vary based on your use case.

Next Steps

To learn more about the different high-availability architectures and their supported configurations, please consult the individual guides.

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