I wish to enable multipath storage access on the compute nodes. i have running instances on the compute nodes already. I need to change nova.conf on the compute nodes for this value:

iscsi_use_multipath = True

Actually this config item is changed to the following:

volume_use_multipath=true

And then I need to restart nova-compute service

systemctl restart openstack-nova-compute.service

Now can this be done safely with running instances? Or do I need to live migrate or shutdown instances first before running this restart?