openstack/ironic
Code Issues Proposed changes

CI: Only artificially pin down the mtu in multinode

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So the prime driver behind pinning the MTU down on our interfaces is so
traffic can cross mutlinode vxlan tunnels between nodes where the devstack
plugin is executing to support more complex tests.

But the reality is that doesn't always make sense, and when Neutron
has a default mtu override based upon "upstream" traffic constraints,
that is likey okay as well.

Part of the CI configuration auto-pins the MTU down, which is fine
for single node testing, however with multinode we need to pin the
MTU further down to try and prevent packets from being dropped on
the internal interfaces use to wire up test VMs.

Change-Id: Idc145f4eea87a8db69202b8d7953975d7d5cba2c
This commit is contained in:
Julia Kreger 2025-02-10 08:32:31 -08:00
parent 9cf39b3769
commit ec53c6b5d2
2 changed files with 12 additions and 3 deletions
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7
devstack/lib/ironic
View File

@ -1446,6 +1446,13 @@ function configure_ironic_inspection_network {
}
function configure_ironic_provision_network {
if [[ "$HOST_TOPOLOGY" == "multinode" ]]; then
# This should artificially drop the default before we get any
# further into the overall process, as post neutron setup, before
# the plugin proceeds past neutorn, this gets set. Which is fine, but
# if we're in a multinode topology, we need to pin this down to match.
iniset $NEUTRON_CONF DEFAULT global_physnet_mtu "$PUBLIC_BRIDGE_MTU"
fi
configure_neutron_dhcp_enable_addr6_list
if [[ "$IRONIC_IP_VERSION" == "6" ]]; then
# NOTE(TheJulia): Ideally we should let this happen

8
devstack/settings
View File

@ -27,7 +27,9 @@ fi
# The overhead is essentially another 78 bytes. In order to
# handle both cases, lets go ahead and drop the maximum by
# 78 bytes, while not going below 1280 to make IPv6 work at all.
PUBLIC_BRIDGE_MTU=${OVERRIDE_PUBLIC_BRIDGE_MTU:-$((local_mtu - 78))}
if [ $PUBLIC_BRIDGE_MTU -lt 1280 ]; then
PUBLIC_BRIDGE_MTU=1280
if [[ "$HOST_TOPOLOGY" == "multinode" ]]; then
# This logic is to artificially pin down the PUBLIC_BRIDGE_MTU for
# when we are using mutlinode architecture, as to transfer the
# bytes over the multinode VXLAN tunnel, we need to drop the mtu.
PUBLIC_BRIDGE_MTU=${OVERRIDE_PUBLIC_BRIDGE_MTU:-$((local_mtu - 78))}
fi