Using Rolling Kernel Switch

The rolling kernel switch (RKS) allows a new kernel to be imported into an ABAP system or specific parameter changes to be activated while the system runs.

Prerequisites

You have permission System(RKS).

For more information, see Standard Permissions.
You have prepared your systems for using RKS.

For more information, see the Application Help for Rolling Kernel Switch on SAP Help Portal at https://help.sap.com/viewer/p/SAP_NETWEAVER_750 and search for Preparing RKS.
You have configured RKS and made any necessary parameter changes before starting the RKS procedure.

For more information, see Rolling Kernel Switch Repositories.
You have configured the system appropriately to ensure that the workload expected can be handled even if an SAP NetWeaver Application Server for ABAP instance is stopped.
You use logon groups instead of a fixed logon to a specific server and make sure that at least two active instances belong to one logon group.
The enqueue and message servers run on the same ASCS instance. You do not have any instances running in which enqueue services or message server services are configured.

Note Do not configure an additional gateway in the ASCS instance because this gateway will fail when the ASCS instance is restarted.
There are no SAP NetWeaver Application Server for Java and dual-stack instances in the system.
There are at least two active SAP NetWeaver Application Server for ABAP instances in the system.
There are no SAP NetWeaver Application Server for ABAP instances running in which enqueue work processes are configured.
There are no SAP NetWeaver Application Server for ABAP instances running in which a message server is configured.
Spool, batch, and update processes are active in at least two SAP NetWeaver Application Server for ABAP instances.
VMC is active in at least two SAP NetWeaver Application Server for ABAP instances, or not in any SAP NetWeaver Application Server for ABAP instance. Internal system RFC destinations must not connect to one single instance (either as the target machine or as the gateway option) because they will fail when this instance is restarted. Instead, use RFC destinations with load balancing.

Recommendation

Avoid long-running applications (for example batch jobs) during the time an RKS is scheduled.
Avoid other systems scheduling activities in the system where you want to run the RKS.

Context

To keep any adverse effects on business operations to a minimum when importing a new kernel version, instances are restarted one after another. This means that at least one application server instance is always available for business operations during the RKS procedure. The order in which the individual instances are restarted enables you to import a new kernel version without any system downtime.

Procedure

Choose Operations.
Choose Systems from the tabs.
From the Operations dropdown for the system where you want to use RKS, choose Kernel Update (Rolling Kernel Switch).
Choose  Parameters Required.
Select the configured RKS configuration that you want to use.
Optional: To perform an RKS restart of the system, for example to update profile parameters, select the True radio button.
Optional: To execute a kernel upgrade, proceed as follows:
1. Read SAP Note 1872602 .
2. Select the Execute Upgrade checkbox.
Choose Set.
Specify a soft timeout in seconds.

The soft timeout specifies how long users are allowed to remain on an application server instance that is to be restarted next. If this timeout is exceeded, all users are automatically logged out and any running applications are closed. If you want to avoid killing long-running processes, for example, background jobs, set the timeout to a higher value than the default value.
Specify a wait timeout in seconds.

SAP Landscape Management waits until the wait timeout is reached before starting an instance. If the wait timeout expires, RKS continues with the next instance
Optional: SAP Landscape Management checks if intersystem dependencies are defined, either performs the necessary action or prompts you to decide whether to proceed with the operation. To ignore intersystem dependencies defined, select the Ignore Intersystem Dependencies checkbox.
Optional: Select the Set Note checkbox and enter a note to be displayed in the Description column of the instance.
Choose Execute.

Results

You can manage activities related to the operation that is currently running.

For more information, see Performing Operations on Activities.
You can view the log of all tasks involved in the process.

For more information, see Working with Logs.