CentOS 7.4 Install SSH issues (PXE Netinstall)

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JohanElmis
Posts: 2
Joined: 2017/09/21 21:13:56
Location: Sweden

CentOS 7.4 Install SSH issues (PXE Netinstall)

Post by JohanElmis » 2017/09/21 21:49:04

Hi,

I have a quite complicated kickstart-file that I'm giving the servers during PXE booting.
Changes needed between 7.1, 7.2 and 7.3 have been minimal.
But with 7.4 it was a complete stop.

It did PXE boot, and got a IP, DNS and so on, but after the squash-image where the installation starts - it no longer had any DNS resolvers.
Figured out that I had to add this line in the kickstart-file:

network --device eth0 --bootproto=dhcp
# And this is despite setting ip:eth0:dhcp in the kopts.

The problem I have now is that I can't SSH to the box during installation ( and I do pass inst.sshd as kopts), and that it gets a different group on the ssh keys, which results in that SSHD refuses to start even if the machine completes.
During the whole installation I can see that sshd is running with the anaconda config - but it's not listening to port 22.

When creating the filesystem under /mnt/sysimage - the keys in /etc/ssh/ are owned by root:ssh_keys (group 999).
In /mnt/sysimage/etc/ssh/ the keys are also assigned the same ID's - the problem though is that group 999 belongs to 'input', and that the ssh_keys at the same time is group=996.

Having the 'input' group and 640 rights on the key-files prohibits SSHD to load them as they are too open.
If I change the group from input to ssh_keys - sshd starts just fine.

Starting to run out of ideas.
Does things get installed in the wrong order?
Why is it "ignoring" my kopts - It worked just fine in earlier CentOS 7 versions.
Why is input getting group id 999 instead of ssh_keys, alternatively - why is the installer using the squash-image groupid's to set on the files in the sysimage - when they are different.

I'm not using biosdevicename in these tests - but have servers where I need the Predictable names as well. But I have not gotten that far in my tests yet.

Thanks, Johan
Sr. Systems Administrator

pjwelsh
Posts: 2632
Joined: 2007/01/07 02:18:02
Location: Central IL USA

Re: CentOS 7.4 Install SSH issues (PXE Netinstall)

Post by pjwelsh » 2017/09/26 18:08:41

I feel your pain with the 7.4 being a bit more of a challenge. We are not able to PXE install under 7.4 kernels yet either. Running PVM CentOS VM's have required the "kernel-plus" kernel to continue to function.

JohanElmis
Posts: 2
Joined: 2017/09/21 21:13:56
Location: Sweden

Re: CentOS 7.4 Install SSH issues (PXE Netinstall)

Post by JohanElmis » 2017/10/05 22:33:22

Hi,

I have managed to sort it out. The problem described was not in CentOS 7.4, but in Cobbler.

It keeps the ssh_keys from the Squash-image to the new system, but gets a wrong group.
I have a patch for the snippet keep_files, that I will submit in the morning.

To get network working I had to add a line in the KS-file - that I didn't have in any other 7.X file.

network --device eth0 --bootproto=dhcp

Good luck.
Sr. Systems Administrator

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