https://netplan.io/design requirements section includes "ethtool settings", but that is the only mention of ethtool on the netplan web site
Based on the hint in netplan.io/faq, I put the "ethtool -G" command in /etc/networkd-dispatcher/configured.d/01ringbuffer
This is on a system with network interface bonding
/var/log/syslog shows the ring buffer setting applied (I added a "logger" message to make it visible) in the same second as bond0 coming online -- the ring buffer setting is logged first but the timestamp on the two lines is identical to the second
How can I ensure the ring buffer size change always happens before the bond comes online? Changing the ring buffer size takes the interface offline briefly, which has been observed to lead to link aggregation group id change, which mucks up the bond throughput (we're using mode 4 bonding, for HA and load balancing, and we want all the interfaces in the same aggregation group).
I am concerned I may have a race between the ring buffer change and bond0 coming up... I tried using "configuring.d" but then some of the lower interfaces got configured before the bond, and some after.
Related: - How to permanently disable TSO & GSO in Ubuntu 18.04 - https://unix.stackexchange.com/questions/542546/what-is-the-systemd-native-way-to-manage-nic-ring-buffer-sizes-before-bonded-int (from my colleague)