[lustre-discuss] peculiar LNet behavior on 2.12.0

[Riccardo Veraldi]

Hello,

I have a new Lustre cluster 2.12.0 with 8 OSSes and 24 clients on RHEL76.

I have a problem with lnet behavior.

even thought I configured lnet.conf in this way on every client

ip2nets:
  - net-spec: o2ib0
    interfaces:
       0: ib0

when I check the lnet status on each client, sometimes is like this as 
it should be:

lnetctl net show
net:
     - net type: lo
       local NI(s):
         - nid: 0 at lo
           status: up
     - net type: o2ib
       local NI(s):
         - nid: 172.21.52.145 at o2ib
           status: up
           interfaces:
               0: ib0


but other times it shows a tcp instance that I did not configure in 
lnet.conf

lnetctl net show

net:
     - net type: lo
       local NI(s):
         - nid: 0 at lo
           status: up
     - net type: tcp
       local NI(s):
         - nid: 172.21.42.245 at tcp
           status: up
     - net type: o2ib
       local NI(s):
         - nid: 172.21.52.145 at o2ib
           status: up
           interfaces:
               0: ib0


I configured the clients to connect through o2ib to the MDS and not tcp 
but somwhat LNet automatically from time to time adds the tcp net instance.

This does not happen on the OSS side but only on the clients side.

I thought I could just use o2ib without a net type tcp instance but LNet 
likes to add it automatically eventually.

How to prevent this ?

thank you


Riccardo