From 3f4631b84d5871633b39cde223ce4a3554669acb Mon Sep 17 00:00:00 2001 From: Alexandra Molnar Date: Fri, 17 Jan 2025 10:30:11 +0000 Subject: [PATCH] OCPBUGS-43683: Clarify MTU configuration in SR-IOV network node policy --- modules/nw-sriov-networknodepolicy-object.adoc | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/modules/nw-sriov-networknodepolicy-object.adoc b/modules/nw-sriov-networknodepolicy-object.adoc index 78cc2fc2c439..086c07f44453 100644 --- a/modules/nw-sriov-networknodepolicy-object.adoc +++ b/modules/nw-sriov-networknodepolicy-object.adoc @@ -57,7 +57,15 @@ To avoid a node in an unhealthy MCP from blocking the application of node networ <5> Optional: The priority is an integer value between `0` and `99`. A smaller value receives higher priority. For example, a priority of `10` is a higher priority than `99`. The default value is `99`. -<6> Optional: The maximum transmission unit (MTU) of the virtual function. The maximum MTU value can vary for different network interface controller (NIC) models. +<6> Optional: The maximum transmission unit (MTU) of the physical function and all its virtual functions. The maximum MTU value can vary for different network interface controller (NIC) models. ++ +[IMPORTANT] +==== +If you want to create virtual function on the default network interface, ensure that the MTU is set to a value that matches the cluster MTU. + +If you want to modify the MTU of a single virtual function while the function is assigned to a pod, leave the MTU value blank in the SR-IOV network node policy. +Otherwise, the SR-IOV Network Operator reverts the MTU of the virtual function to the MTU value defined in the SR-IOV network node policy, which might trigger a node drain. +==== <7> Optional: Set `needVhostNet` to `true` to mount the `/dev/vhost-net` device in the pod. Use the mounted `/dev/vhost-net` device with Data Plane Development Kit (DPDK) to forward traffic to the kernel network stack.