Cluster installation

IBM® Safer Payments is typically installed in a clustered environment that involves multiple instance nodes.

The connection from the IBM Safer Payments user interface to the cluster can be configured in different ways. The user interface is also called the client component.

Only one instance serves user requests at a time (active API) in a cluster. The API of all other instances of the cluster remains deactivated to most user requests, which prevents inconsistent data object changes. All instances with deactivated API are still accessible through its API for certain administration tasks, in particular, cluster administration. If the server instance with the active API becomes unavailable, the administrator can use any other instance to switch the active API.

The API activation must not be switched between instances when the current active API instance still has outgoing messages to be synchronized to other instances. If all instances are synchronized, the administrator can freely switch the API activation between instances. The switch is done either from the Administration > Clusters page or remotely by scripts that send the enableApi request. When the API is switched to another instance, all user sessions to the current instance are terminated, and all unsaved data of the users is lost.

The simplest implementation of user access in a cluster is to configure one instance that is dedicated for the active API. If the instance fails or is down and users need to be able to continue working, the API must be activated on another server instance in the same cluster. The users must resume working on this instance, but at a different IP and port. This implementation is normally sufficient for a cluster installation with few users, for example, installations that do not use case investigation, analysis, and reporting, or where user access is not 24 x 7.

If many users are accessing the cluster, it is a best practice to use an external fail-over switch that automatically routes user requests to the instance with active API. Users access the API with a fixed IP address and port even if the active API is switched between instances.