Description of problem: The RHEL OSP Installer does not have a setting for desired MTU on tenant network interface on hosts. The MTU on the Compute hosts and Neutron Networker is important because it is a dependency for setting the network_device_mtu in nova and the veth_mtu in the openvswitch config on the compute hosts and the networker node. Performance in VMs is greatly increased by setting the MTU inside the VM to use jumbo frames, but that requires the entire path to have high MTUs (OVS veth, VM network device, and host physical interface). For that reason the MTU should be set in the /etc/sysconfig/ifcfg-X for the physical interfaces that are used for tenant networks. Version-Release number of selected component (if applicable): 1:1.5.0-0.6.RC2.el6ost How reproducible: Deploy OpenStack using the RHEL OSP Installer, there is no MTU set in the interface config. Steps to Reproduce: 1. Install RHEL OSP Installer 2. Deploy OpenStack 3. Check interfaces on compute hosts and network controller Actual results: No MTU is set, so the interface default is used Expected results: There should be a UI element to set the interface MTU, right next to the place where the interface is chosen for tenant networks (in the Deployment configuration) Additional info: There should really be a warning that the MTU on the switch ports must also be set at least as high as the chosen MTU, otherwise the custom MTU may cause connectivity problems.
In testing, I found the following performance variance: Netperf TCP_SENDFILE 60-Second Transfer, average Cross-rack, VM MTU 1500: 1.45 Gb/s Cross-rack, VM MTU 8950: 7.39 Gb/s Same-rack, VM MTU 1500: 1.95 Gb/s Same-rack, VM MTU 8950: 8.3 Gb/s
Verified: FailedQA Environment: rhel-osp-installer-client-0.5.1-1.el7ost.noarch ruby193-rubygem-staypuft-0.5.2-1.el7ost.noarch ruby193-rubygem-foreman_openstack_simplify-0.0.6-8.el7ost.noarch openstack-foreman-installer-3.0.4-1.el7ost.noarch openstack-puppet-modules-2014.2.6-1.el7ost.noarch rhel-osp-installer-0.5.1-1.el7ost.noarch It's possible to set the MTU for neutron in the UI, but the kickstart template for the host isn't updated as a result of the change.
As a point of information, it will only set it on the tenant interface. It does not set it for all interfaces. Can you please verify that?
Verified: Environment: openstack-puppet-modules-2014.2.6-1.el7ost.noarch rhel-osp-installer-0.5.1-1.el7ost.noarch ruby193-rubygem-foreman_openstack_simplify-0.0.6-8.el7ost.noarch rhel-osp-installer-client-0.5.1-1.el7ost.noarch openstack-foreman-installer-3.0.5-1.el7ost.noarch ruby193-rubygem-staypuft-0.5.3-1.el7ost.noarch There's a "Tenant Network Device MTU" field in the "Services Configuration" page in the deployment wizard. Verified that the value specified in the MTU field is actually being set in the kickstart for the deployed hosts.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHBA-2015-0156.html