NFSROOT and lagg(4)

[Konstantin Belousov]

On Sat, Feb 04, 2017 at 01:44:21PM -0700, Sean Bruno wrote:
> "what I want" is to pxe/netboot and then switch over to using a lagg(4)
> interface that includes the interface used in the pxe/netboot boot up.
> I suspect, I have to switch to MDROOT to do this, but I thought I'd ask
> if anyone is doing this type of configuration in their labs?
> 
> What seems to happen is that I lose the nfsroot when I reconfigure the
> lagg, and I no longer have access to reconfigure.
> 
> e.g. pxeboot from em0, then reconfigure networking to use em0/em1 in lagg0:
> 
> em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
> 
> options=5259b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,TSO4,LRO,WOL_MAGIC,VLAN_HWFILTER,VLAN_HWTSO>
>         ether 00:30:18:c5:0a:a9
>         nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
>         media: Ethernet autoselect (1000baseT <full-duplex>)
>         status: active
> em1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
> 
> options=5259b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,TSO4,LRO,WOL_MAGIC,VLAN_HWFILTER,VLAN_HWTSO>
>         ether 00:30:18:c5:0a:a9
>         nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
>         media: Ethernet autoselect (1000baseT <full-duplex>)
>         status: active
> lagg0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
> 
> options=5259b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,TSO4,LRO,WOL_MAGIC,VLAN_HWFILTER,VLAN_HWTSO>
>         ether 00:30:18:c5:0a:a9
>         inet 192.168.100.53 netmask 0xffffff00 broadcast 192.168.100.255
>         nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
>         media: Ethernet autoselect
>         status: active
>         groups: lagg
>         laggproto lacp lagghash l2,l3,l4
>         laggport: em0 flags=1c<ACTIVE,COLLECTING,DISTRIBUTING>
>         laggport: em1 flags=1c<ACTIVE,COLLECTING,DISTRIBUTING>
> 

Look at reroot support, see reboot(8) option -r. I suspect you could
need two reroots: first to some tmpfs or memory backed md(4) where
ifconfig is present to reconfigure interfaces, second to boot into the
final root.