The N+1 node cluster configuration model supports the rolling upgrade method for upgrading the Avaya Breeze® platform servers within the cluster.
To use the rolling upgrade method, ensure the following:
All nodes within that cluster are currently functional.
The cluster must be provisioned such that if one node out of the N+1 nodes is out of service, the remaining nodes within that cluster have enough capacity to support the Device Adapter endpoints that got unregistered from the unavailable node.
The rolling upgrade procedure is as follows:
Stop the service at the node where you want to upgrade Avaya Breeze® platform. The endpoints on this node register with the remaining nodes within the cluster.
Upgrade Avaya Breeze® platform on the node where the service is stopped.
When the upgrade is complete, put the node back into service.
Similarly, upgrade the other nodes within the cluster.
Caveats
In an N+1 node cluster configuration, if one or more nodes are either not functional or are not reachable, the rolling upgrade method would not reduce the end-user impact because of the following reason:
If one node is out of service, the cluster is effectively an N node cluster. The remaining nodes do not have the capacity to support all the endpoints that were served by the node that became unavailable.
