Which file stops a Red Hat (or Fedora) from moving to another partition?

[saikee]

Introduction

I have an obsession of packing a large number of distros into one hard disk. Many distro installers do not like it even though their kernels can support higher number partitions. Typically an installer, say from a Debian family, would freeze when checking a hard disk that has more than 15 partitions. However if I put the same distro on a hard disk with less than 16 partition the installer will be very happy to install. I then copy the distro back to the original disk to a different partition, change the boot loader setting and fstab and the new distro will be happily working in the next hard disk that has 57 partitions.

This scheme works for any distro until recently Fedora refuses the move. I didn't investigate the cause then but I have just come up against a brick wall with the Red Hat Enterrise Linux 6. It was one out of the 4 I just moved. The others are operating happily.

The problem

The RHEL will boot to a Grub screen. When I select the user account and type in the password it just refreshes the screen as though the password could not be accepted.

Cure attempt 1

I can boot up another Linux, mount the RHEL partition, change root to it and change my normal user password. Better still why don't I create a new user and another password.

Same result. I could not pass the log in screen with revised password or from a new account which got displayed.

Cure attempt 2

How about a little trick told by Justlinux library file --> to alter the run level.

So I mounted the RHEL partition, changed root to it, edited the /etc/inittab and amended the run level from 5 (for X desktop) to 1 (single user - terminal mode).

RHEL now boots to a root terminal! Success in a sense that my RHEL boots as expected and there was never a problem with booting. However newer Linux do not permit root log on to the desktop so I cannot check the log in with the ordinary user account to X.

After I fiddled with the various files/parameters related to the gdm and X still no joy so I cut my loss and post the question here.

It could be something very simple with you guys dealing with servers all day.

[x]

My first guess is that the partition where /home resides is full, this since you can log in as root but not as user.

[saikee]

X,

Thanks for the suggestion. I am afraid this happens when the installation is new and the /home really hasn't got time to get filled up yet. I have /home as part of the / and this is what RHEL 6 is being reported

[root@saikee-desktop-ext4 /]# df
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/sda18            19228276   3136636  15114892  18% /
sysfs                 19228276   3136636  15114892  18% /sys
[root@saikee-desktop-ext4 /]#

I changed root from Ubuntu to investigate the RHEL 6 in sda18.

[x]

Hmmm tricky...
Let's see now if I get you right:
You can boot to graphic login-screeen, right? (You say "The RHEL will boot to a Grub screen. When I select the user account and type in the password " but I believe you mean gdm - no user account in grub.. )

Now I've never used RHEL, but has had similar problems a few times.
Some tips to try:
1. Can user log in to console?
If so, try issuing "startx" as user - not from runlevel 1 though. I always make runlevel 3 = everything except gdm/kdm & X, do that and run startx. (And just in case you don't know: switch runlevel with "init 3" )
If it doesn't work you'll get errors on the screen.
If it works - well, at least you've gotten somewhere... Most likely a problem w gdm then.

2. To allow root-logon to GUI you need to change config for gdm. In Ubuntu it's in the file /etc/gdm/gdm.conf guess it's the same for RHEL.
Should be a line
AllowRoot=false
change to "true" and restart gdm.
If root can logon to desktop there's probably a permission issue.

3. Check the logs. /var/log/Xorg.0.log as well as the file .xsession-errors residing in users home-dir. Could give useful info.

[saikee]

x,

I am afraid your idea is good but can't be applied to RHEL. I suppose the Red Hat Enterprise Linux doesn't get to its dominant position in the server market without some nice security features and I am probably hitting one of them.

If I cannot log in then the information of /var/log/Xorg.0.log doesn't help. my current /var/log/Xorg.0.log in the RHEL partition shows no error.

I am aware of the trick to alter the gdm.conf but RHEL does not do it or if it does it is hidden somewhere, as the my interrogation below shows

[root@saikee-desktop /]# ls /etc/gdm/*.conf
/etc/gdm/custom.conf
[root@saikee-desktop /]# cat /etc/gdm/*.conf
# GDM configuration storage

[xdmcp]

[chooser]

[security]

[debug]

I might have to dig a lot deeper.

[TheCatMan]

Just a quick thought, I know Red Hat has used SELinux for a while now, does it run it in enforcing mode by default? If so, maybe your user doesn't have any access rights to the new partition.

[saikee]

TheCatMan,

Sounds like the culprit I have been looking for. Thanks.

Will look into it and report.

Edited --------------------------------------

Hit the bull eye. It was Selinux as suggested by TheCatMan I temporarily disable it and now post this reply from RHEL-6. The file controlling it is /etc/selinux/config. It is the same for the Fedora too.

[impert]

I wonder if you could have got there by booting in single user mode and then changing the passwords (including the root password) with passwd?

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[saikee]

mpert,

I was able to boot in single user mode by altering the inittab but that does not need a password and root is automatically given.

There is nothing wrong with the password but the selinux simply shutdown everyone include root. I even created a new user in single mode but the login was denied same as other users.

Once I disabled the selinux I got everything back to normal.

Fedora and RHEL are 2 of the 30 Linux I am migrate from a 1TB hard disk to a 1.5TB hard disk. In the past before Selinux I was able freely to move them around between hard disk and partitions. I think the server grade distros are better protected with selinux.

[impert]

Saikee,
Thanks for the reply. I asked because doing this has fixed strange things for me in other distros. I have no knowledge of RHEL or selinux, but I thought the selinux config file might have been automagically updated when the root password was re-set. Apparently not, then.
Off topic, but: some day you must do a how-to on keeping all those systems up-to-date.