Bug 1138958
| Summary: | RFE Set MTU to 1400 in dnsmasq-neutron.conf if VXLAN or GRE are being installed | |||
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| Product: | Red Hat OpenStack | Reporter: | John Fulton <johfulto> | |
| Component: | openstack-packstack | Assignee: | Javier Peña <jpena> | |
| Status: | CLOSED ERRATA | QA Contact: | Itzik Brown <itbrown> | |
| Severity: | unspecified | Docs Contact: | ||
| Priority: | medium | |||
| Version: | 5.0 (RHEL 7) | CC: | afazekas, aortega, chale, derekh, dnavale, ichavero, johfulto, jpena, jschluet, jswensso, mmagr, myllynen, nyechiel, oblaut, tfreger, yeylon | |
| Target Milestone: | z5 | Keywords: | FutureFeature, ZStream | |
| Target Release: | 5.0 (RHEL 7) | |||
| Hardware: | Unspecified | |||
| OS: | Unspecified | |||
| Whiteboard: | ||||
| Fixed In Version: | openstack-packstack-2014.1.1-0.47.dev1288.el7ost | Doc Type: | Enhancement | |
| Doc Text: |
With this update, a new feature in Packstack detects if VXLAN or GRE encapsulation is being used for OpenStack Networking tenant networks. If detected, it configures the DHCP agent to use a lower MTU for instances (1400 bytes). This is due to the fact that when using encapsulation, the VXLAN or GRE headers add some bytes to the Ethernet packet. If the instance MTU has the same size as the host MTU, some packets may be too large, resulting in slow network performance. As a result of this new feature, the lower MTU ensures the network traffic to instances performs adequately.
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Story Points: | --- | |
| Clone Of: | ||||
| : | 1148044 (view as bug list) | Environment: | ||
| Last Closed: | 2015-09-10 11:36:27 UTC | Type: | Bug | |
| Regression: | --- | Mount Type: | --- | |
| Documentation: | --- | CRM: | ||
| Verified Versions: | Category: | --- | ||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | ||
| Cloudforms Team: | --- | Target Upstream Version: | ||
| Embargoed: | ||||
| Bug Depends On: | ||||
| Bug Blocks: | 1148044 | |||
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Description
John Fulton
2014-09-06 18:39:27 UTC
*** Bug 1138954 has been marked as a duplicate of this bug. *** The neutron puppet module has a network_device_mtu parameter i think this change should be done in packstack and the other installers that use the module to install and configure neutron. Is this acceptable? Having packstack and other installers set the network_device_mtu parameter in puppet seems reasonable to me. I will update bugs. (In reply to Ivan Chavero from comment #3) > The neutron puppet module has a network_device_mtu parameter i think this > change should be done in packstack and the other installers that use the > module to install and configure neutron. > > Is this acceptable? I have done a test with network_device_mtu=1400. In this case, all ports created inside the network node netns use mtu=1400, however the guest mtu is still 1500. Would this be enough to fix the performance issue? Just confirmed it is not enough, we need to set the guest MTU as specified in the KB article. Proposed patch https://review.openstack.org/132888 for review. -- Fedora Bugzappers volunteer triage team https://fedoraproject.org/wiki/BugZappers Checked with version: openstack-packstack-puppet-2014.1.1-0.47.dev1288.el7ost.noarch openstack-packstack-2014.1.1-0.47.dev1288.el7ost.noarch 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-2015-1746.html |