Changes in Libvirt XML File of VM are Lost After a Hard Reboot.

Problem

• The changes made to the libvirt.xml file of a VM using were lost post a hard reboot.

Environment

• Platform9 Managed OpenStack - v4.0 and Higher
• Libvirt
• Nova

Cause

Starting with Juno( or Kilo ) release libvirt.xml cannot be modified manually. A hard reboot will recreate libvirt.xml, dropping all the updates and restoring the XML file to the original state.

Resolution

1. Currently, there is no way to make the changes persist after a hard reboot but we can make the changes and perform a soft reboot for the changes to take effect.
2. Edit the XML file using the virsh edit command

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# sudo virsh edit [VM uuid]

3. Perform a soft reboot of the VM either from the Platform9 Management Plane UI or use the following command

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# opensgtack server reboot [VM uuid]

4. Avoid a Hard reboot of a VM to ensure the changes made above persist.