[root@localhost ~]# cat > secret.xml <<EOF
> <secret ephemeral='no' private='no'>
>         <usage type='ceph'>
>                 <name>client.libvirt secret</name>
>         </usage>
> </secret>
> EOF
[root@localhost ~]# virsh secret-define --file secret.xml
Secret b6d26377-a700-bd77-9b1e-c9226f35d1f5 created
[root@localhost ~]# ceph auth list -m 10.10.10.10
[...]
client.libvirt
        key: AQDvdh5S8ET+JhAAfRKRuuZo2pWQwy13xUWFLA==
        caps: [mon] allow r
        caps: [osd] allow class-read object_prefix rbd_children, allow rwx pool=libvirt-pool
[root@localhost ~]# cat > client.libvirt.key
AQDvdh5S8ET+JhAAfRKRuuZo2pWQwy13xUWFLA==
[root@localhost ~]# virsh secret-set-value --secret b6d26377-a700-bd77-9b1e-c9226f35d1f5 --base64 $(cat client.libvirt.key)
Secret value set

[root@localhost ~]# vi sr.xml

<pool type='rbd'>   
  <name>ceph</name> 
  <source>
    <name>rbd</name>
    <host name='10.11.4.52' port='6789'/>
    <auth username='client.libvirt'>
      <secret type='ceph' uuid='b6d26377-a700-bd77-9b1e-c9226f35d1f5'/>
    </auth>
  </source>
</pool>

[root@localhost ~]# xe sr-create type=libvirt name-label=ceph device-config:xml-filename=sr.xml
Error code: libvirt
Error parameters: libvirt: VIR_ERR_65: VIR_FROM_30: Invalid secret: virSecretFree