Triggering a virtual server dump on the host

Use the virsh dump command to trigger a dump of a running or of a crashed virtual server.

About this task

A running virtual server is paused and continues operations when the dump process that is triggered with virsh dump is complete.

You might have set up an automated dump for a crashed virtual server, for example kdump or in the virtual server configuration. Use virsh dump to obtain a dump of a virtual server if no such automation or automated restart is in place. The virtual server must be configured to preserve the memory if a crash occurs.

You can also use virsh dump for a dump of a none-responding virtual server.

Procedure

Create a dump by issuing a command of this form:

# virsh dump --memory-only <VS> <dumpfile>

<dumpfile>: Is the name of the dump file. If no fully qualified path to the dump file is specified, it is written to the current working directory of the user who issues the virsh dump command.
<VS>: Is the name of the virtual server as specified in its domain configuration-XML file.

Results

The dump is written to the file <dumpfile>.

What to do next

To inspect the dump, enter the command:

# crash <dumpfile> <kernel-image-filename>

<kernel-image-filename>: Is the name of the kernel image file of the guest running on the dumped virtual server.