[lxc-users] LXD: lxc copy and /etc/hostname

[Brian Candler]

Hello,

What's the mechanism by which when you do "lxc copy foo bar", the "bar" 
gets into /etc/hostname? Is this logic inside lxd itself, or inside 
cloud-init, or somewhere else?

The reason I ask: I am creating instances whose FQDN is e.g. 
"srv2.campus5.example.com". lxd does not allow dots in container names, 
so I have to give them names like "srv2-campus5" instead. But then 
that's what ends up in /etc/hostname as well.

Clearly I can just overwrite /etc/hostname and restart the container, 
but I wondered if there was a cleaner way, and that in turn led me to 
try and find out how it gets set in the first place, and I couldn't find it.

Reading issue #1921, I tried setting lxc.utsname before starting the 
container, but this didn't make a difference:

$ lxc copy srv-master foobar
$ lxc config set foobar raw.lxc lxc.utsname=wibble
$ lxc config set foobar user.fqdn bibble
$ lxc start foobar
$ lxc exec foobar bash
root at foobar:~# hostname
foobar
root at foobar:~# cat /etc/hostname
foobar

And if I change the profile of srv-master so that it's on a bridge with 
no DHCP service before copying, the copy still seems to pick up the 
hostname.

Thanks,

Brian.