VLAN
This article shows how to configure a network interface as an IEEE 802.1q VLAN trunk.
Note: Alpine Linux v2.4 or later is required
Installation
First, install the vlan package. This will give you support for vlans in the /etc/network/interfaces file.
apk add vlan
Configuration
Edit the /etc/network/interfaces file:
auto eth0.8 iface eth0.8 inet static address 192.168.0.2 netmask 255.255.255.0 gateway 192.168.0.1
With the vlan package installed ifup will find the trailing .8 in eth0.8 and will create a vlan interface with vid 8 over eth0.
Alternative with vlan8 over eth0:
auto vlan8 iface vlan8 inet static address 192.168.0.2 netmask 255.255.255.0 gateway 192.168.0.1 vlan-raw-device eth0
In those examples a static ip address was used but it works with dhcp as well.