lxd unit not getting IP due to wrong mac address in 99-juju.yaml

[Andy Wu]

saw this issue in recent jammy-yoga deployment , out of 82 lxd units, one or two units stuck in pending state.

affected lxd units didn't get IP address on eth0 which cause it fail to fetch juju-agent and complete cloud-init

looks like caused by mistach mac address between eth0 and /etc/netplan/99-juju.yaml

root@juju-da5b98-4-lxd-3:~# ip address show eth0
124: eth0@if125: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 6a:1f:3c:45:9f:60 brd ff:ff:ff:ff:ff:ff link-netnsid 0

but /etc/netplan/99-juju.yaml has different mac

root@juju-da5b98-4-lxd-3:~# grep eth0 /etc/netplan/99-juju.yaml -C 10
network:
  version: 2
  ethernets:
    eth0:
      match:
        macaddress: 00:16:3e:f6:5a:59 ---> different MAC

Workaround is to change the 99-juju.yaml to make sure eth0 MAC address matches the real one of eth0 , but I wonder what caused juju to program the wrong mac address in first place ?

full logs here:

https://pastebin.canonical.com/p/YJ8R4TBJxF/

juju version : 2.9.38
lxd: 5.0.1-9dcf35b