After redoing the installation by hand, I have more information, so therefor I am editing my post completely so it's better readable and hopefully someone can provide a workable solution or workaround for this issue.
I am using an OpenVZ container and was trying to do an automated install of Debian 9 (Stretch), however that failed for numerous reasons. So I am now doing it differently. I do an automated install of Debian 8 and after that I do an in-place upgrade to Debian 9.
If I do this manually it works, but when I do it automatically it hangs on two (2) different dialog screens. When I do it manually, then I am presented with 2 dialog screens. Both these screens are simply answered with an "ENTER"-press. I don't need to fill in anything. One is purely a warning about the older kernel, but pressing "ENTER" it will make the installation continue. The other dialog screen is about wide-dhcpv6-client. Also this screen can be passed by simply pressing "ENTER".
However during an automated installation, it hangs on both of these dialogs. Since you don't get a screen with an automated install, there is no way to continue. So it waits on input, before it can continue.
I have everything related two these issues noted down below.
The first time it hangs, is on the old kernel message:
root 10918 10890 0 16:15 pts/0 00:00:00 dialog --backtitle Package configuration --title Configuring libc6 --output-fd 11 --nocancel --msgbox Kernel version not supported This version of the GNU libc requires kernel version 3.2 or later. Older versions might work but are not officially supported. Please consider upgrading your kernel. 11 75
This is purely a warning message (I cannot update the kernel, so that's not possible, because of the OpenVZ). If I run the update by hand (manually), I can simply pass this by pressing "ENTER". That's it.
The 2nd time it hangs is on wide-dhcpv6-client
root 19436 19428 0 16:44 pts/0 00:00:00 /usr/bin/dpkg --status-fd 29 --configure man-db:amd64 mlocate:amd64 wide-dhcpv6-client:amd64
root 19437 19436 6 16:44 pts/0 00:00:00 /usr/bin/perl -w /usr/share/debconf/frontend /var/lib/dpkg/info/wide-dhcpv6-client.postinst configure 20080615-12
root 19443 19437 0 16:44 pts/0 00:00:00 /bin/sh /var/lib/dpkg/info/wide-dhcpv6-client.config configure 20080615-12
root 19445 19437 0 16:44 pts/0 00:00:00 dialog --backtitle Package configuration --title Configuring wide-dhcpv6-client --output-fd 11 --nocancel --inputbox Network interfaces on which the DHCPv6 client sends requests should be specified here. Multiple interfaces are separated with spaces. An empty line temporarily disables dhcp6c. Interfaces on which the DHCPv6 client sends requests: 11 78
I can also pass this dialog, when I do the installation by hand (manually), by simply pressing "ENTER".
I also took 2 screenshots of both issues below.
- Kernel message dialog: https://i.imgur.com/26eD8uq.jpg
- wide-dhcpv6-client dialog: https://i.imgur.com/7IZD4ki.jpg
In both cases (when installing it manually) pressing "ENTER" is sufficient, or by selecting "OK" ofcourse.
I already tried many things to avoid these dialog screens during an automated install, but failed so far. I am really clueless here.
For example I tried several things with the option "debconf-set-selections" but no luck. Also I tried setting the installation to "noninteractive", but still the same results. All other options, questions, etc. are passed without issues, only these two dialogs.
I hope someone can provide a solution or a workaround for this.
