lvupdateSafeKE Command

Purpose

The lvupdateSafeKE command is a utility that manipulates the list of safe kernel extensions for the AIX® Live Update operation.

Syntax

lvupdateSafeKE  [ -a kext_path [-p] | -r kext_path | -l ]

Description

During a Live Update operation, a new logical partition (LPAR) is dynamically created and booted with the updated AIX kernel. When the new LPAR is booted, the device drivers are reloaded while the devices are configured. The lvupdateRegKE command can be used to specify commands to be executed during a Live Update operation to load other kernel extensions. After the new LPAR is prepared, the active workload from the original LPAR is checkpointed and restarted from the same point on the new LPAR.

By default, any data from the kernel extensions is not checkpointed. If there is no state data in a kernel extension, reloading the kernel extension on the new LPAR does not cause any problems while the applications are checkpointed and restarted. This condition makes a kernel extension Live Update safe. A kernel extension can be made safe by registering scripts to be executed during the Live Update operation that either capture any necessary state information and restore it on the new LPAR, or quiesce any subsystems that are necessary to ensure that there is no state data in the kernel extension.

A kernel extension that is in the safe kernel list ensures that if it is loaded, it does not prevent a Live Update operation. If a Live Update operation fails because of a loaded kernel extension that is not in the safe list, an error with the kernel extension name is logged under the /var/adm/ras/liveupdate/logs directory. Kernel extensions can also be marked safe by specifying the SYS_LUSAFE flag when you load the extension by using the sysconfig() system call. The lvupdateSafeKE command does not list the extensions that were marked safe by using this method.

To bypass the check for safe kernel extensions, the Live Update operation must be started with an lvupdate.data file that has the entry, kext_check = no.

Note: Any kernel extension that is to be loaded during the Live Update operation must be in one of the following five file systems: /, /var, /usr, /opt, /tmp.

Parameters

Item	Description
`kext_path`	A string of up to 1024 characters that specifies the full path of a kernel extension.

Flags

Item	Description
-a `kext_path`	Adds a kernel extension to the list that indicates that it is safe for the Live Update operations.
-l	Lists the set of kernel extensions that are specified as safe for the Live Update operation.
-p	Specify the `-p` flag with the `-a` flag to indicate that the kernel extension can be ignored while checking preview. However, do not use this flag during the Live Update operation.
-r `kext_path`	Removes a kernel extension from the list.

Examples

To add a kernel extension to the safe list for the Live Update operation, enter the following command:
```
# lvupdateSafeKE -a /usr/lib/drivers/mydev_driver
```
To list the kernel extensions that are registered as safe, enter the following command:
```
# lvupdateSafeKE -l
```
To remove a kernel extension from the safe list, enter the following command:
```
# lvupdateSafeKE -r /usr/lib/drivers/mydev_driver
```