Open Infrastructure

Messages of boot:

 * Checking local filesystems  .../dev/sda3: clean, 9406/3399680 files, 466640/13579494 blocks
/dev/sda1: clean, 25/25688 files, 28145/102400 blocks
 [ ok ]
 * Remounting root filesystem read/write ... [ ok ]
 * Remounting filesystems ... [ ok ]
 * Activating swap devices ... [ ok ]
 * Mounting local filesystems ... [ ok ]
 * Configuring kernel parameters ... [ ok ]
 * Creating user login records ... [ ok ]
 * Wiping /tmp directory ... [ ok ]
 * Setting hostname ... [ ok ]
 * Setting keymap ... [ ok ]
 * Starting networking ... *   lo ... [ ok ]
 *   eth0 ...udhcpc: started, v1.31.0
udhcpc: sending discover
udhcpc: sending discover
udhcpc: sending discover
udhcpc: sending discover
udhcpc: sending discover
udhcpc failed to get a DHCP lease
udhcpc: no lease, forking to background
 [ ok ]
 * Starting busybox syslog ... [ ok ]
 * Initializing random number generator ... [ ok ]
 * Starting busybox acpid ... [ ok ]
 * Starting chronyd ... [ ok ]
 * Starting busybox crond ... [ ok ]
 * /run/radvd: creating directory
 * /run/radvd: correcting owner
 * Enabling IPv6 forwarding ... [ ok ]
 * Starting IPv6 Router Advertisement Daemon ... [ ok ]
 * Starting sshd ... [ ok ]

Welcome to Alpine Linux 3.11_alpha20190707 (edge)
Kernel 4.19.62-0-vanilla on an x86_64 (/dev/ttyS0)

blue login: 

This config does NOT hang at boot:

blue:/etc/network# cat interfaces 
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet dhcp
    hostname blue

#        post-up /usr/bin/wg-quick up wg0

#iface eth0 inet6 static
#        address 2a0a:e5c1:122:f00d::42
#        netmask 64

#auto eth1
#iface eth1 inet dhcp
#        post-up /usr/bin/wg-quick up wg0

#iface eth1 inet6 static
#        address 2a0a:e5c1:122:cafe::42
#        netmask 64

This config hangs again:

blue:~# cat /etc/network/interfaces 
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet dhcp
    hostname blue

#        post-up /usr/bin/wg-quick up wg0

#iface eth0 inet6 static
#        address 2a0a:e5c1:122:f00d::42
#        netmask 64

auto eth1
#iface eth1 inet dhcp
#        post-up /usr/bin/wg-quick up wg0

iface eth1 inet6 static
        address 2a0a:e5c1:122:cafe::42
        netmask 64

Trying as suggested in #alpine-linux:

blue:~# rc-update del radvd
 * service radvd removed from runlevel default

Result with previously hanging config: still hanging

Work around:

auto eth0
iface eth0 inet dhcp
    hostname blue
        post-up ip addr add 2a0a:e5c1:122:f00d::42/64 dev eth0
        post-up /usr/bin/wg-quick up wg0