Description of problem: hi, from bug https://bugzilla.redhat.com/show_bug.cgi?id=1750606#c19 for now the default nic MTU is 1500 in vsphere coreos image. Can we update the default MTU to 1600 or more. since the Geneve Requires configuring transport networks with an MTU size of at least 1600 bytes Version-Release number of selected component (if applicable): Red Hat Enterprise Linux CoreOS 42.80.20190916.0 4.18.0-80.11.1.el8_0.x86_64 How reproducible: always Steps to Reproduce: 1. setup cluster with OVN network type on vsphere 2. 3. Actual results: The cluster cannot be setup Expected results: Additional info:
hi, can we build a new coreos image for vsphere with default MTU is 1600 to have a try. since this block our OVN installation. thanks
I'm not sure this is the issue. 1500 should be the correct MTU.
Based on the linked comment from BZ#1750606, Geneve requires an MTU of 1600 or greater. See the docs: https://docs.vmware.com/en/VMware-Validated-Design/4.3/com.vmware.vvd.sddc-nsxt-design.doc/GUID-3FF2471C-665B-4E84-8DE4-ED3F35A58DE8.html If we were to change this from the default of 1500, there is likely larger implications for installing OCP/RHCOS when *not* using OVN/Geneve. I spoke with Joe Callen about this and he recommended that we use Terraform via the Installer to configure the MTU when using OVN on vSphere. Re-assigning to Installer.
Networking is the responsibility of network operator. It's the one that setups and enabled ovn for cluster, it should be the one making those modifications.
We don't need 1600 MTU. Sorry for the noise.