bug#52682: installer freezes when ci.guix.gnu.org cannot be reached

[Mathieu Othacehe]

Hey Ricardo,

> address.  I forgot to add a line to /etc/hosts to resolve
> ci.guix.gnu.org to the local IP.  When I started the installation it
> would print two lines and then seemingly freeze.

I can replicate this issue in a VM, by disconnecting the host network in
the middle of the installation.

I can also replicate it by running a "guix system init
~/guix/gnu/system/examples/desktop.tmpl /tmp" and blocking Berlin IP
while the command is running, this way: "sudo iptables -A INPUT -s
141.80.181.40 -j DROP". The init command hangs forever.

So looks like the freeze issue goes beyond the installer frame and is
more a Guix issue.

In the meantime, we could also extend the installer connectivity check
to make sure that ci.guix.gnu.org is available before proceeding to the
installation.

Thanks,

Mathieu