Comment 1 for bug 1771335

Thanks for filing this bug in Ubuntu.

I tried a simple case of bringing up two lxd containers, one with haproxy as the frontend, another one with just apache as the backend, and this config file on the frontend:

(defaults from the package go here)
frontend mycontainer
 bind *:9090
 mode http
 default_backend myapache

backend myapache
 mode http
 balance roundrobin
 server apache-1 bionic-backend.lxd:80 check

I then rebooted this frontend and it picked up the bionic-backend.lxd ip just fine via dns.

This sounds indeed like some sort of race condition during boot. It happens only after you reboot a machine? After the boot, if you login and issue a "systemctl restart haproxy", it then works?

Could you share some details about the networking setup of this machine? For example:
cat /etc/network/interfaces /etc/network/interfaces.d/*
cat /etc/netplan/*.yaml
cat /etc/hosts
cat /etc/resolv.conf

Also, does this machine have a wired network connection, or does it depend on wifi and someone logging in on gnome to activate network-manager and its wifi connection?