I have a docker installed on a openstack VM. What should be the exact MTU size for my docker bridge network so that containers can able to communicate outside. Most of the post are suggesting to set it to 1400. I am looking, what should be the exact size with good explanation.
As OpenStack uses VXLAN tunnels for communication. VXLAN tunnel has 50 bytes reserved for the headers. Suppose host machine NIC has MTU of 1500 then OpenStack VMs will have MTU of 1450. So ideally docker bridge should have MTU size <= 1450.