Description of problem:
The original design goal behind using OVS as the bonding mechanism in TripleO was simplicity: since OVS was being used for bridging, adding bonding support directly to the OVS bridge made sense.
Unfortunately, in a few large-scale deployments with high traffic, packet loss has been observed in OVS bonds using LACP.
To counteract this behavior, support was added to TripleO to support Linux kernel-mode bonds, which are not susceptible to packet loss at scale.
When using OVS bonds, an OVS bridge is required. This necessitated the use of a bridge even on the storage nodes, where this wouldn't be required if using kernel bonds.
Now that we have the option of using kernel-mode bonds, we recommend this in most cases, unless an OVS-specific bonding mode is required (although different packet loss issues have occurred when using balance-slb mode bonds, see https://bugzilla.redhat.com/show_bug.cgi?id=1289962).
The sample bonding templates included with OSP 8 are configured for OVS bonds.
The proper use of Linux bonds should be properly documented, and we should provide equivalent sample templates that show the optimum use of Linux bonds.
The following applies when using Linux bonds instead of OVS bonds:
* Bond interfaces use "linux_bond" instead of "ovs_bond" for the type:
* Templates use "bonding_options" instead of "ovs_options" for the bond options
* Linux kernel bonding options have a different form, such as "mode=802.3ad" to indicate LACP bonding. For more info, see https://www.kernel.org/doc/Documentation/networking/bonding.txt
* Bridges must still be used for interfaces used for Neutron tenant or provider VLANs, or for SNAT/Floating IPs, whether or not bonding is used on a particular interface. These bridges can be OVS bridges or Linux bridges, but OVS bridges provide more features.
*** Bug 1310982 has been marked as a duplicate of this bug. ***
I updated the network iso section to include linux_bridge and linux_bond options:
I've also included links to the kernel bond params in Red Hat Enterprise Linux 7 Networking Guide.
Was this what you were after? Let me know if there's anything else I should add.
No response in over a month. Closing this BZ. However, if further changes are required, please feel free to reopen this BZ.