Add Watchdog Device to KVM Instance

Watchdog is an Oracle Linux service that runs in the background to monitor host availability and processes and reports back to the kernel.

The following information describes how to install the watchdog software package and enable its service. It also includes information about how to configure the watchdog daemon configuration file, and how to add watchdog settings to the XML configuration file for a KVM instance.

Note:

Watchdog device configurations aren't supported on Arm-based KVMs. Arm-based KVMs are cloud-native virtual machines that operate on Arm-based processors.

What Do You Need?

Administrator privileges.
Existing KVM instance on host system.
For details, see Create: KVM Instance.

Steps

Follow these steps to install and enable watchdog, update the watchdog daemon configuration as needed, and update the guest OS configuration file to include watchdog settings.

Install the Watchdog software package and enable the watchdog service on the guest OS.
Example command syntax:
```
sudo dnf install watchdog
sudo systemctl enable --now watchdog.service
```
Note:
The latest version of libvirt (9.x or later) includes a number of Watchdog enhancements and bug fixes over the earlier versions of libvirt.

The Watchdog service immediately starts and runs in the background.
Configure the watchdog service as needed for the guest OS.
The watchdog.conf file includes all Watchdog configuration properties. For more details, see the watchdog.conf(5) Linux manual page.
Shut down the KVM instance.
For details, see KVM: Shut Down Instance.

Add watchdog settings to the guest OS XML configuration file.

Use the virsh edit command to edit the guest OS XML configuration.
For example:
```
virsh edit My_KVMGuest_Name                           
```
Note:
The virsh edit command opens the XML file in the text editor specified by the $EDITOR shell parameter. The vi editor is set by default.

Update the guest OS XML configuration file to include the required watchdog device settings.

For example:

<devices>
     ...
     </input>
     <input type='mouse' bus='ps2'/>
     <input type='keyboard' bus='ps2'/>
     <watchdog model='i6300esb' action='poweroff'/>
     <graphics type='vnc' port='-1' autoport='yes'>
       <listen type='address'/>
     </graphics>
     ...
</devices

Where:

model – Specifies the emulated watchdog device driver. Valid property values are specific to the KVM machine type, for example:

Model Values	Description
i6300esb	The recommended device, which emulates an Intel 6300ESB.
ib700	Emulates an ISA iBase IB700, and is only compatible with the i440fx/pc machine type. Note: This device doesn't work with the q35 machine type.

action – (Optional) Describes the action taken when the watchdog timer expires.

Action Value	Description
reset	(Default option) Forcefully resets the guest VM.
shutdown	(Not recommended) Gracefully powers off the guest OS. Important: The shutdown action requires that the guest is responsive to ACPI signals. In cases where the watchdog timer expired, the guests are typically unable to respond to ACPI signals. Therefore assigning a 'shutdown' action isn't recommended.
poweroff	Forcefully powers off the guest VM.
pause	Suspends the execution of the guest OS.
none	Does nothing.
dump	Automatically creates a dump file containing the core of the guest virtual machine so that it can be analyzed. Note: To configure the directory to save the dump file, set the `auto_dump_path` in file `/etc/libvirt/qemu.conf`.
inject-nmi	Injects a non-maskable interrupt to the guest OS.

Save the guest OS XML configuration changes.

Start the KVM instance.
For details, see KVM: Start Instance.
The Watchdog service starts and runs immediately after a power reset.