there is a case:
ip= is used, usually
here is the logic :
down by default
ip=, according to
<device> Name of network device to use.
Default: If the host only has one device, it is used.
Otherwise the device is determined using
autoconfiguration. This is done by sending
autoconfiguration requests out of all devices,
and using the device that received the first reply.
using the device that received the first reply, and brings up eth1, but keep eth0
down at it's default state.
eth1 according to
eth1 has no internet connection
this patch let alpine init bring up all interfaces before
grep operstate and find the first one that is
up, which is eth0. this fixes the boot issue in such case.
without this patch, one has to use parameter
ip=:::::eth0:dhcp (parsed by linux kernel and alpine init) or
BOOTIF=eth0_macaddr (parsed by alpine init)