[Lustre-devel] security: MGS connection

[Eric Mei]

Eric,

Here is an updated user interface proposal, please review:

- MGS can be configured to "only allow RPC with certain level of 
security from certain node". The default is 'allow any'.

- Each node choose what security flavor to use to connect MGS when 
mounting target device or client, by mount option "mgssec=flavor". By 
default 'null' (no protection) is chosen.

- For MDT/OST, the option "mgssec=flavor" could also be written on disk, 
like other parameters, but will be override if mount option supplied.

- If flavor of GSS/Kerberos is specified, some pre-configured machine 
credential will be used, so no need to supply password or whatsoever.

- The flavor of MGS connection won't change until umount, no matter how 
rest of connection flavors change at runtime.

- If there's multiple mounts on one node, they must specify the same 
security flavor. For example, if we do:
   # mount -t lustre -o mgssec=krb5p /dev/sda1 /mnt/ost1
   # mount -t lustre -o mgssec=null /dev/sda1 /mnt/ost2
then the second mount will fail immediately.

-- 
Eric