Hello.
Thanks a lot Erik my problem was the MTU. 
if I go back to a situation with MTU=1500 everywhere, all is working fine !!! 

Is the following configuration possible and if so, how to configure with kolla-ansible files ? :

3 networks:
  - external (2 externals, VLAN 10 and VLAN 20): MTU = 1500
- admin:MTU=1500
- management : MTU = 9000 (a scsi bay stores volumes, with mtu 9000 ok).

Like this: 
`
Thanks a lot if you have a solution for this.
If  impossible, I stay with 1500… it’s working, no problem.

Franck 


Le 12 nov. 2022 à 21:00, Franck VEDEL <franck.vedel@univ-grenoble-alpes.fr> a écrit :

3) Networking issues like mismatched MTU

My MTU (between nodes ) is 9000…. 

I believe my problem is the  MTU.

I modified /etc/kolla/config/neutron.conf and /etc/kolla/config/neutron/ml2_conf.ini.conf
then kolla-ansible -i multinode reconfigures


I test again everything and functions that did not work work again but not all....

For example, instances get an ip through dhcp but can't ping the router, but on some networks it works.
However, before the reboot of the servers, I had not had a problem with the MTU of 9000.

I'm going back to a 1500 MTU on Monday on site.

Thank you Eric!!!

Franck VEDEL