In these notes the node to be added is cld-np-19.cloud.pd.infn.it
Disable the node so that no new VMs will be scheduled on this host. Instructions: Disable a compute node howto
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Verify that a ssh from root@cld-log to root@<hostname> root@cld-np-19 works without requiring password
Enable the host:
openstack compute service set --enable cld-np-19.cloud.pd.infn.it nova-compute