[systemd-devel] Systemd setup DSA interfaces in port mode and bond them together?

[Brian Hutchinson]

Hi Mikulėnas,

On Tue, Nov 16, 2021, 3:12 AM Mantas Mikulėnas <grawity at gmail.com> wrote:

> Most of this looks like it could be done with systemd-networkd to create a
> bond .netdev, with a small oneshot service for i2c. (What's the exact
> criteria for when it should be run? Does it depend on bond0 being there,
> does it need to be last, etc?)
>

It can be last in the startup chain I guess, don't know what other systemd
things that might need the network to be up before the last unit file runs.

I start linuxptp too so I would have the unit file that starts ptp4l start
after the bond was created etc.

Same thing for the i2c command to enable the switch.

Regards,

Brian


> On Tue, Nov 16, 2021, 02:58 Brian Hutchinson <b.hutchman at gmail.com> wrote:
>
>> Hi,
>>
>> I'm on a IMX8 platform and have a Microchip KSZ9567 Ethernet switch.  I
>> can use IP commands to manually bring lan1 and lan2 interfaces up and then
>> create a redundant/failover bond ... but I'm having difficulty figuring out
>> how to do this the "systemd" way.
>>
>> My first attempt was to just have systemd run a script of all the
>> commands I do manually but during system startup there appears to be race
>> conditions so I have to set my service type to "Idle" and sometimes even
>> that doesn't work. So I want to exploit any systemd support for DSA and
>> bonding.
>>
>> Here is script my manual steps which is what I want systemd to ultimately
>> do:
>>
>> #!/bin/bash
>>
>> # Create a redundant bond between ksz9567 DSA lan1 and lan2 interfaces
>>
>> # Load bonding kernel module
>> modprobe bonding
>>
>> # Bring up CPU interface (cpu to switch port 7 - the RGMII link)
>> ip link set eth0 up
>>
>> # Create a bond
>> echo +bond0 > /sys/class/net/bonding_masters
>>
>> # Set mode to active-backup (redundancy failover)
>> echo active-backup > /sys/class/net/bond0/bonding/mode
>>
>> # Set time it takes (in ms) for slave to move when a link goes down
>> echo 1000 > /sys/class/net/bond0/bonding/miimon
>>
>> # Add slaves to bond
>>
>> echo +lan1 > /sys/class/net/bond0/bonding/slaves
>> echo +lan2 > /sys/class/net/bond0/bonding/slaves
>>
>> # Set IP and netmask of the bond
>> ip addr add 192.168.0.4/24 dev bond0
>>
>> # And bring bond up.  Pings and network connectivity should work now
>> ip link set bond0 up
>>
>> # For a board that doesn't have Ethernet switch hardware strapped to
>> enable at boot .. enable it now
>> i2cset -f -y 0 0x5f 0x03 0x00 0x01 i
>>
>> Thanks for any information, pointers etc.
>>
>> Regards,
>>
>> Brian
>>
>
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