How can the SPICE password of a libvirt+kvm+qemu virtual machine be changed while the machine is running?

Solution 1:

In order to be able to change the SPICE access password without a stop/start of the VM, the VM must already be equipped with a password. SPICE passwords cannot be added/removed without a restart.

Under this prerequis, we have two options to achieve this:

A: solution with virt-xml

Use the command virt-xml [-c qemu+ssh://host/system] name-of-the-vm --edit all --graphics password=verys3cr3t --update

B: solution with virsh

1. virsh [-c qemu+ssh://host/system] dumpxml --security-info name-of-the-vm > output.xml
2. look for the block <graphics type='spice' port='5900' autoport='no' listen='0.0.0.0' passwd='testpass'>...</graphics> and isolate it, throw the rest away, save the graphics XML block under graphics.xml
3. Change the passwd attribute to the new desired password
4. virsh [-c qemu+ssh://host/system] update-device name-of-the-vm graphics.xml