Shutdown actions

Red Hat Enterprise Linux 9.2 LPAR mode z/VM guest KVM guest

Several triggers can cause Linux® to shut down. For each shutdown trigger, you can configure a specific shutdown action to be taken as a response.

Table 1. Shutdown triggers and default action overview
Trigger	Command or condition	Default shutdown action
halt	Linux shutdown -H command	stop
poff	Linux poweroff or shutdown -P command	stop
reboot	Linux reboot or shutdown -r command	reipl
restart	Depending on the hyperisor environment: LPAR A PSW restart on the HMC z/VM® A CP system restart command KVM A virsh command on the KVM host	stop
panic	Linux kernel panic	stop

The available shutdown actions are summarized in Table 2.

Table 2. Shutdown actions
Action	Explanation	See also
stop	For `panic` or `restart`, enters a disabled wait state. For all other shutdown triggers, stops all CPUs. For Linux on KVM, frees the resources that were used by the Linux instance. Depending on your virtual server configuration, the memory might be preserved.	n/a
ipl	Performs an IPL according to the specifications in /sys/firmware/ipl.	Displaying current IPL parameters
reipl	Performs an IPL according to the specifications in /sys/firmware/reipl.	Rebooting from an alternative source
dump	For Linux in LPAR mode and Linux on z/VM, creates a dump according to the specifications in /sys/firmware/dump.	Using the Dump Tools on Red Hat Enterprise Linux 9.2, SC34-7751
dump_reipl	For Linux in LPAR mode and Linux on z/VM, performs the `dump` action followed by the `reipl` action.	Using the Dump Tools on Red Hat Enterprise Linux 9.2, SC34-7751
vmcmd	For Linux on z/VM, issues one or more z/VM CP commands according to the specifications in /sys/firmware/vmcmd.	Configuring z/VM CP commands as a shutdown action

Use lsshut to find out which shutdown action is configured for each shutdown trigger.

Use the applicable command to configure the shutdown action for a shutdown trigger:

For halt, power off, and reboot use chshut.
For restart and panic on Linux in LPAR mode or Linux on z/VM, use dumpconf, see Using the Dump Tools on Red Hat Enterprise Linux 9.2, SC34-7751

kdump for restart and panic

If kdump is set up for a Linux instance, kdump is started to create a dump, regardless of the shutdown actions that are specified for restart and panic. With kdump, these settings act as a backup that is used only if kdump fails.

Note: kdump is not a shutdown action that you can set as a sysfs attribute value for a shutdown trigger. See Using the Dump Tools on Red Hat Enterprise Linux 9.2, SC34-7751 about how to set up kdump.