[TriLUG] esxi does not want to mount my iscsi lun

[Mauricio Tavares via TriLUG]

So, I can see the lun using "esxcli iscsi session connection list"

[root at vmhost2:~] esxcli iscsi session connection list
vmhba64,iqn.2000-01.com.synology-iSCSI:fileserver.01,00023d000002,0
   Adapter: vmhba64
   Target: iqn.2000-01.com.synology-iSCSI:fileserver.01
   ISID: 00023d000002
   CID: 0
[...]
   SessionCreateTime: 08/07/18 01:15:32
   ConnectionCreateTime: 08/07/18 01:15:32
   ConnectionStartTime: 08/07/18 01:15:33
   State: logged_in
[root at vmhost2:~]

But when I do "esxcli storage vmfs extent list" I only see the local
datastores.
 What am I missing to manually add the lun being provided as a datastore?