High availability overview

NQRust-Identity 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 two high availability architectures in which to deploy NQRust-Identity: Single-cluster deployments and Multi-cluster deployments.

Single-cluster deployments

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

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 NQRust-Identity pods

Multi-cluster deployments

Connect two NQRust-Identity clusters deployed for example in different Kubernetes clusters in two availability zones or data centers with the required network latency and database configuration.

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