Chapter 7. 3scale High Availability and Evaluation templates

This document describes the templates for High Availability and Evaluation used by Red Hat 3scale API Management 2.7 installation.

Prerequisites

  • You need to have an available OpenShift cluster to deploy elements of the High Availability and Evaluation templates.
Important

The 3scale High Availability and Evaluation templates are a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process. For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.

To deploy High Availability and Evaluation templates, perform the steps outlined in the following sections:

7.1. High Availability template

The High Availability (HA) template allows you to have a HA setting for critical databases.

Prerequisites

  • Before deploying the HA template, you must deploy and configure the external databases, and configure them in a HA configuration with a load-balanced endpoint.

Using the HA template

For HA, the template named amp-ha-tech-preview.yml allows you to deploy critical databases externally to OpenShift. This excludes:

  • Memcached
  • Sphinx
  • Zync

Differences between the standard amp.yml template and amp-ha-tech-preview.yml include:

  • Removal of the following elements:

    • backend-redis and its related components
    • system-redis and its related components
    • system-mysql and its related components
    • Redis and MySQL related ConfigMaps
    • MYSQL_IMAGE, REDIS_IMAGE, MYSQL_USER, MYSQL_ROOT_PASSWORD parameters
  • By default, increased from 1 to 2 the number of replicas for non-database DeploymentConfig object types.

  • Addition of the following mandatory parameters, allowing you the control of the location of external databases:

    • BACKEND_REDIS_STORAGE_ENDPOINT
    • BACKEND_REDIS_QUEUES_ENDPOINT
    • SYSTEM_REDIS_URL
    • APICAST_STAGING_REDIS_URL
    • APICAST_PRODUCTION_REDIS_URL
    • SYSTEM_DATABASE_URL

With amp-ha-tech-preview.yml, you need to configure database connections (excluding system-memcache, zync-database and system-sphinx that do not contain permanent data) out of the cluster via the newly added mandatory parameters. The endpoints require database load-balanced connection strings, including authentication information. Also, for the non-database deployments, the number of pod replicas is increased to 2 by default to have redundancy at application-level.

7.1.1. Setting RWX_STORAGE_CLASS for high availability

ReadWriteMany (RWX) PersistentVolumeClaims (PVCs) uses the storage class RWX_STORAGE_CLASS.

required: false

value: null

  • Set this to null to signal OpenShift that you want the storage class to be auto-discovered (no value).
  • If you set this to an empty string or no default value, it signals OpenShift that you want the string storage empty. This is an invalid setting.

7.2. Evaluation template

For evaluation purposes, there is a template named amp-eval-tech-preview.yml that deploys a 3scale environment without resource requests nor limits.

The only functional difference compared to the standard amp.yml template is that the resource limits and requests have been removed. This means that in this version the minimum hardware requirements have been removed on the pods at CPU and Memory level. This template is intended only for evaluation, testing, and development purposes as it tries to deploy the components in a best-effort way with the given hardware resources.