The error (libvirtd.log):

qemu-system-x86_64: -drive file=gluster://cs1-i/havana_novagluster/ed4de3c3-1567-4d67-bc29-e3b10e5db22f/disk,if=none,id=drive-virtio-disk0,cache=none: Gluster connection failed for server=cs1-i port=0 volume=havana_novagluster image=ed4de3c3-1567-4d67-bc29-e3b10e5db22f/disk transport=tcp

The libvirt.xml:

    <disk type='network' device='disk'>
      <driver name='qemu' cache='none'/>
      <source protocol='gluster' name='havana_novagluster/ed4de3c3-1567-4d67-bc29-e3b10e5db22f/disk'>
        <host name='cs1-i' transport='tcp'/>
      </source>

I have also tried declaring:

   <disk type='network' device='disk'>
      <driver name='qemu' cache='none'/>
      <source protocol='gluster' name='havana_novagluster/ed4de3c3-1567-4d67-bc29-e3b10e5db22f/disk'>
        <host name='cs1-i' port='6000' transport='tcp'/>
      </source>

but get the same error except with port=6000 instead of port=0