There was a (Confidential) presentation available from Layer7 how to upgrade a Layer7 Gateway Cluster with no downtime. But there are some terms (jgroups config) that I cannot place. Somehow I think this presentation is outdated.
So is an actual document or presentation available which describes how to upgrade a API Gateway with zero downtime?
The functionality of jGroups is to facilitate the multicast replay protection capabilities of the SecureSpan Gateway (SSG). In order to enforce such protection, each SSG node in a cluster must be registered with the jGroups cluster.
I think this is still applicable for recent Gateway versions.
The older presentation is outdated as in later versions we moved away from jgroups and are using hazelcast to handle internode communication for tracking unique ID in tokens and such. Most of the content from the old presentation is sound but untested for some time. We have seen a lot of customers move towards a separate cluster instance for the upgrade so that the switch over is done at the load balancer level.
Can you please explain more about your last line? What do you mean by "move towards a separate cluster instance"?
The method I brought up is outlined here: Upgrade Scenario 1 - Database with the Gateway - CA API Gateway - 9.3 - CA Technologies Documentation. It is called our expedited upgrade procedure and it involves standing up a new cluster on the latest release and migrating over the old system database. This will allow both to be running at the same time so you can use your load balancer to control the flow of traffic as you move from one version of the gateway to another.