Migrating an existing high availability (HA) setup to a cluster setup requires you to first remove the NetScaler appliances from the HA setup and create a backup of the HA configuration file. You must then use the two appliances to create a cluster and upload the backed-up configuration file to the cluster.
- Before uploading the backed-up HA configuration file to the cluster, you must modify it to make it cluster compatible. Refer to the relevant step of the procedure below.
- Use the batch -f <backup_filename> command to upload the backed-up configuration file.
The above approach is a very basic migration solution which results in downtime for the deployed application. As such, it must be used only in deployments where there is no consideration to application availability.
However, in most deployments, the availability of the application is of paramount importance. For such cases, you must use the approach where an HA setup can be migrated to a cluster setup without any resulting downtime. In this approach, an existing HA setup is migrated to a cluster setup by first removing the secondary appliance and using that appliance to create a single-node cluster. After the cluster becomes operational and serves traffic, the primary appliance of the HA setup is added to the cluster.