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mikenash
28-Nov-2014, 15:21
Fresh install.
display-manager.service - X Display Manager
Loaded: loaded (/usr/lib/systemd/system/display-manager.service; enabled)
Active: failed (Result: exit-code) since Fri 2014-11-28 08:18:44 EST; 39min ago
Process: 1594 ExecStart=/usr/lib/X11/display-manager start (code=exited, status=6)

Nov 28 08:18:44 linux-rsvc systemd[1]: Starting X Display Manager...
Nov 28 08:18:44 linux-rsvc display-manager[1594]: /etc/vconsole.conf available
Nov 28 08:18:44 linux-rsvc display-manager[1594]: KEYMAP: us
Nov 28 08:18:44 linux-rsvc display-manager[1594]: Command: localectl set-keymap us
Nov 28 08:18:44 linux-rsvc display-manager[1594]: Starting service gdm..unused
Nov 28 08:18:44 linux-rsvc systemd[1]: display-manager.service: control process exited, code=exited status=6
Nov 28 08:18:44 linux-rsvc systemd[1]: Failed to start X Display Manager.
Nov 28 08:18:44 linux-rsvc systemd[1]: Unit display-manager.service entered failed state.

x0500hl
15-Dec-2014, 14:27
Mike,

I am also running SLES 12 on System z (base install with no maintenance) but I don't have a major problem with xwindows. I was able to launch the xclock program after starting Xming on my PC. I checked the output of 'ps efH' and there aren't many entries containing 'x' and none with 'disp'. I found that I can't launch firefox. I simply get 'Killed' back a few seconds after trying to launch it.

Will xclock launch on your PC? Maybe the display-manager daemon doesn't need to be running in SLES 12. IDK.

I went to yast | System | Services Manager and Enabled then Started 'display-manager'. When I issued the Start the display showed that it was Enabled and Active. I selected Show Details and the pop-up appeared


display-manager.service - X Display Manager
Loaded: loaded (/usr/lib/systemd/system/display-manager.service; enabled)
Active: inactive (dead)


I clicked OK to save the configuration and 'ps -efH' still shows nothing. I then reentered Services Manager in yast and display-manager is Inactive.

Harley

mikenash
08-Jan-2015, 21:32
Hello Harley, I apologize for not replying but I did not have anything to add. I am a new to Linux environment and did not understand what you were doing with the xclock program. I also posted in the boot install forum with out any response that would assist me with debugging this error. Have you made any progress. Any suggestions to gather diagnostic information. Any information about how the display manager process initialization is suppose to work that may determine where it went wrong?

jmozdzen
13-Jan-2015, 11:20
Hi mikenash,

Hello Harley, I apologize for not replying but I did not have anything to add. I am a new to Linux environment and did not understand what you were doing with the xclock program. I also posted in the boot install forum with out any response that would assist me with debugging this error. Have you made any progress. Any suggestions to gather diagnostic information. Any information about how the display manager process initialization is suppose to work that may determine where it went wrong?

I'd suggest to have a look into /var/log/Xorg.0.log (or whichever log file relates to your X-server instance - use "ls -lrt /var/log" to receive a file listing with the most recently updated log files at the end of the list). That's the log file of the X server, which usually lists errors via entries marked "EE".

Regards,
Jens

mikenash
13-Jan-2015, 23:10
Hi mikenash,


I'd suggest to have a look into /var/log/Xorg.0.log (or whichever log file relates to your X-server instance - use "ls -lrt /var/log" to receive a file listing with the most recently updated log files at the end of the list). That's the log file of the X server, which usually lists errors via entries marked "EE".

Regards,
Jens
Hello Jens, thank you for your response. I do not have any Xorg log files in this directory. Is there a configuration file to turn logging/debugging on? Are there items to check with the initialization of the X display manager. This is a fresh install with YAST but could I have missed checking off something?

jmozdzen
14-Jan-2015, 00:33
Hi mikenash,

Hello Jens, thank you for your response. I do not have any Xorg log files in this directory. Is there a configuration file to turn logging/debugging on? Are there items to check with the initialization of the X display manager. This is a fresh install with YAST but could I have missed checking off something?

I have to admit that I have yet to lay my hands on SLES12 - there's a chance that the file is located elsewhere or named differently. Maybe someone else with SLES12 hands-on experience could confirm this, please?

My assumption is that the desiplay manager failed to start an X server, and was after the X server's error messages. As there might be no X server log file, it might be a failure even before that. Maybe the info from https://help.gnome.org/admin/gdm/stable/troubleshooting.html.en helps debugging this? (It says that gdm error messages go to syslog, which will store those in /var/log/messages by default.)

Regrds,
Jens

mikenash
15-Jan-2015, 20:30
Hello Jens, thank you for your reply. I do not have any X server log messages. I found the /etc/gdm/custom.conf file. I add eEnable=TRUE under [DEBUG]. All other entries are empty. I then rebooted the system and still nothing. I went to the documentation that you pointed to. As I was reviewing I find that there is not /etc/gdm/autostart directory. I then tried starting xdm and display-manager from within yast and received the same error messages. The gdm service was not listed. Next was to start gdm manually. It was not in /sbin/gdm but I did find it in /usr/sbin/gdm. I then received several pages of messages on the console and then the console stall where I had to cntl-c to get out. Also found log files in /var/log/gdm. Most were of the format :0.log... There was one unreadable file called ystemd[1]: Starting X Display Manager... Probably when the terminal hung. I am not sure how to append a file but within the several pages of output I find one common error.
<7>GdmServer: Opening logfile for server /var/log/gdm/:0.log
Failed to execute child process "/usr/bin/X" (No such file or directory)
<5>Could not start the X server (your graphical environment) due to an internal error. Please contact your system administrator or check your syslog to diagnose. In the meantime this display will be disabled. Please restart GDM when the problem is corrected. So I think that missing the autostart directory the configuration was never performed? This created the missing /usr/bin/X file or directory?

jmozdzen
15-Jan-2015, 23:15
Hi Mike,

[...] I do not have any X server log messages.
Failed to execute child process "/usr/bin/X" (No such file or directory)
[...]
So I think that missing the autostart directory the configuration was never performed? This created the missing /usr/bin/X file or directory?

now this explains the missing log file from the X server... *there is no X server* :(

Going back through this thread, I noticed this is on System Z - as far as I know there is no X server on that type of Linux systems, instead you need to run that on your local machine (PC, X Station or similar). So the question is, why does your system try to start an X server at all?

As you are new to Linux, here's some background informartion:

- the X Server is a piece of software that provides facilities to display graphical content and to interact with HIDs (human interface devices, like mouse, keyboard and alike). This software runs on the machine that has graphics hardware, i.e. a PC... but not on System Z, as far as I can tell.

- the X display manager (xdm) is a piece of software that interfaces between the X server and the (Linux) system. Most notably it will present the "login screen" on an X server (not to be confused with the login on non-graphical terminals, where no xdm is involved). Xdm *can* be used to start X servers, which is a typical setup on Linux systems with graphics hardware (i.e. workstations and PCs).

- X programs (like the "xclock" program mentioned by Harley (x0500hl)) run on i.e. a Linux system (your System Z) and use an X Server to provide their graphical output. Hence Harley's mention of xclock was merely that of some simple test program, to prove the functionality of the X Server connection.

Unfortunately, my "big machines" experience ended more than 15 years ago, prior to Linux on System Z times - rather than issuing nonsense configuration recommendations here, I rather offer to ask for someone else to help out.

Are you eligible for SUSE support? In that case you might consider opening a "service request" with SuSE.

Regards,
Jens

malcolmlewis
15-Jan-2015, 23:40
Hi mikenash

Does the system have a graphics adapter as in your sitting in front of
the system with a keyboard, monitor etc?

If so, what does the following command show?


lspci

Else if your using remote access, then how are you accessing the system?

--
Cheers Malcolm °¿° LFCS, SUSE Knowledge Partner (Linux Counter #276890)
SUSE Linux Enterprise Desktop 12 GNOME 3.10.1 Kernel 3.12.28-4-default
If you find this post helpful and are logged into the web interface,
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mikenash
16-Jan-2015, 20:42
The command lspci does nothing on the putty session. I connect to the server using putty, using a PCOMM session to log onto the 3270 console and VNC. Since this is a new install I was reviewing /var/log/messages file and noticed the Failed to start X Display Manager error after the display manager started the gdm service.
Jan 15 14:35:24 linux234 display-manager[663]: Starting service gdm..unused
Jan 15 14:35:24 linux234 systemd[1]: Failed to start X Display Manager.
The reason I was reviewing the /var/log/messages file was because I was working with the VNC server. I was unable to start a second session and I made changes to the /etc/xinetd.d/vnc file to allow a second session. This worked but the vnc sessions did not logout and remain running. This behavior was the same before I made any changes. I found the display manager failure to start and started there. This message was always there. I can do another install and it will be there. So, starting gdm is something Suse does and nothing I initiated. Where would this be initiated from during the boot process?

malcolmlewis
16-Jan-2015, 21:01
On Fri 16 Jan 2015 07:44:02 PM CST, mikenash wrote:


The command lspci does nothing on the putty session. I connect to the
server using putty, using a PCOMM session to log onto the 3270 console
and VNC. Since this is a new install I was reviewing /var/log/messages
file and noticed the Failed to start X Display Manager error after the
display manager started the gdm service.
Jan 15 14:35:24 linux234 display-manager[663]: Starting service
gdm..unused
Jan 15 14:35:24 linux234 systemd[1]: Failed to start X Display Manager.
The reason I was reviewing the /var/log/messages file was because I was
working with the VNC server. I was unable to start a second session and
I made changes to the /etc/xinetd.d/vnc file to allow a second session.
This worked but the vnc sessions did not logout and remain running.
This behavior was the same before I made any changes. I found the
display manager failure to start and started there. This message was
always there. I can do another install and it will be there. So,
starting gdm is something Suse does and nothing I initiated. Where
would this be initiated from during the boot process?




Hi
Via systemd, since it's a remote session set the default to runlevel 3;


systemctl set-default multi-user.target

If you had a display etc and using a graphical desktop, the default
would be set (set-default) to graphical.target.

The command;


systemctl status display-manager.service

Should only be present if it's trying to start up a graphical session,
so this should show as dead.

You can also analyze the startup with systemd-analyze (blame and
critical-chain to see what is starting, when and how long it's taking.

Since your running vnc there should also be some sort of service file
for this.

--
Cheers Malcolm °¿° LFCS, SUSE Knowledge Partner (Linux Counter #276890)
SUSE Linux Enterprise Desktop 12 GNOME 3.10.1 Kernel 3.12.28-4-default
If you find this post helpful and are logged into the web interface,
please show your appreciation and click on the star below... Thanks!

mikenash
19-Jan-2015, 23:53
I installed a new system because I have a better understanding with describing the problem and did not want any previous changes interfer with the debug process.
The VNC server is installed to start automatically. Three consoles are defined; vnc1, vnc2, and vnc3.
The display manager starts but not without errors. I can start a vnc session and logoff will work. I cannot start a second vnc session. As soon as I log in the session will gracefully close. However, I change the config file /etc/xinetd.d/vnc and add AlwaysShared=Yes and then stop the VNC server from automatically starting at IPL. The display manager will fail to start but I am able to start two vnc sessions but logoff does not work. I still can not start a second session when the VNC server starts at IPL time. It appears to not use this config file. I have learned I can start the VNC server at IPL time and manually start a forth vnc server session.
I am going to focus on fixing the VNC server at IPL time. The first vnc session start and behave as I expect. I looked through the menus but did not find any method to change the VNC server configuration with the AlwaysShared parameter. The output for the display manager at IPL time shows probles with configuring gdm display. I will be reviewing the documentation but would not mind more
advice and directions. I did execute the systemd-analyze commands but did not see anything useful but this could be my lack of experience.

Is there a way to append text files to the forum post. I want to avoid pasting in too much information.

Below is the output from the IPL when the VNC server is configured to start at IPL time.

linux234:~ # systemctl status display-manager -l
display-manager.service - X Display Manager
Loaded: loaded (/usr/lib/systemd/system/display-manager.service; enabled)
Active: active (running) since Sun 2015-01-18 17:33:34 EST; 24h ago
Process: 638 ExecStart=/usr/lib/X11/display-manager start (code=exited, status=0/SUCCESS)
Main PID: 698 (gdm)
CGroup: /system.slice/display-manager.service
└─698 /usr/sbin/gdm --no-console

Jan 18 17:33:34 linux234 display-manager[638]: GdmSlaveProxy: Disposing slave proxy
Jan 18 17:33:34 linux234 display-manager[638]: GdmSlaveProxy: Killing slave
Jan 18 17:33:34 linux234 display-manager[638]: GdmDisplay: display lasted 0.017221 seconds
Jan 18 17:33:34 linux234 display-manager[638]: GdmLocalDisplayFactory: display status changed: 4
Jan 18 17:33:34 linux234 display-manager[638]: GdmDisplayStore: Unreffing display: 0x9a2ba520
Jan 18 17:33:34 linux234 display-manager[638]: GdmLocalDisplayFactory: maximum number of X display failures reached: check X server log for errors
Jan 18 17:33:34 linux234 display-manager[638]: GdmDisplay: Disposing display
Jan 18 17:33:34 linux234 display-manager[638]: GdmLocalDisplayFactory: Display 0x9a2ba520 disposed
Jan 18 17:33:34 linux234 display-manager[638]: GdmDisplay: Finalizing display: /org/gnome/DisplayManager/Displays/_5
Jan 18 17:33:34 linux234 display-manager[638]: ..done

mikenash
21-Jan-2015, 22:13
I started the first VNC session and select -> Applications - System Tools - Settings - Sharing. I turn on screen Sharing and Remote Login and save the settings. Next I start the second VNC session and logon. The session starts to open and then is gracefully close. In /var/log/messages for the first VNC session the only odd events are of missing desktop files. There are several: i.e.2015-01-21T15:21:46.674352-05:00 linux140 org.gnome.ControlCenter.SearchProvider[5911]: ** (process:6019): WARNING **: Ignoring broken panel color (missing desktop file). In /var/log/messages for the second VNC session it goes well until this message: 2015-01-21T15:28:45.817355-05:00 linux140 gnome-session[6203]: WARNING: Failed to acquire org.gnome.SessionManager
2015-01-21T15:28:45.819071-05:00 linux140 gdm-password]: pam_unix(gdm-password:session): session closed for user Michael. Not sure where to go from here. Also, is there a method to attach files to these posts? Thanks in advance.

mikenash
23-Jan-2015, 16:19
I missed a command: systemctl set-default multi-user.target
I execute this and peformed a reboot. It got me in troublr. When I start a new VNC session I receive a black screen.
So I executed systemctl set-default default.target or systemctl set-default single-user.target the target can not be found.
How do I restore the initial setting?

malcolmlewis
23-Jan-2015, 17:13
On Fri 23 Jan 2015 03:24:01 PM CST, mikenash wrote:


I missed a command: systemctl set-default multi-user.target
I execute this and peformed a reboot. It got me in troublr. When I
start a new VNC session I receive a black screen.
So I executed systemctl set-default default.target or systemctl
set-default single-user.target the target can not be found.
How do I restore the initial setting?




Hi
Try;


systemctl set-default graphical.target

Which is runlevel 5 multi-user.target is runlevel 3.

You can also use isolate with systemctl to restart the levels... lots
of things to learn with systemd ;)

--
Cheers Malcolm °¿° LFCS, SUSE Knowledge Partner (Linux Counter #276890)
SUSE Linux Enterprise Desktop 12 GNOME 3.10.1 Kernel 3.12.32-33-default
If you find this post helpful and are logged into the web interface,
please show your appreciation and click on the star below... Thanks!

mikenash
25-Jan-2015, 22:25
Thank you, back on track. I start a VNC session and turn on sharing. When I attempt to log onto a second session the session gracefully closes when the password is entered. If I edit the /etc/xinetd.d/vnc file and add AlwaysShared = Yes I am able to start a second session but logout does not work. Anyway, here is the output after the first session is logged in and output after the second session closes. Where would the configuration file be for the VNC server that starts at IPL time? What else can I do to debug this problem. Thanks again.
linux140:~ # systemctl status display-manager -l
display-manager.service - X Display Manager
Loaded: loaded (/usr/lib/systemd/system/display-manager.service; enabled)
Active: active (running) since Sun 2015-01-25 16:09:19 EST; 3min 10s ago
Process: 605 ExecStart=/usr/lib/X11/display-manager start (code=exited, status=0/SUCCESS)
Main PID: 662 (gdm)
CGroup: /system.slice/display-manager.service
├─ 662 /usr/sbin/gdm --no-console
└─1382 /usr/lib/gdm/gdm-simple-slave --display-id /org/gnome/DisplayManager/Displays/__1_2

Jan 25 16:09:19 linux140 display-manager[605]: Failed to execute child process "/usr/bin/X" (No such file or directory)
Jan 25 16:09:19 linux140 display-manager[605]: Could not start the X server (your graphical environment) due to an internal error. Please contact your system administrator or check your syslog to diagnose. In the meantime this display will be disabled. Please restart GDM when the problem is corrected.
Jan 25 16:09:19 linux140 display-manager[605]: GdmDisplay: display lasted 0.011153 seconds
Jan 25 16:09:19 linux140 display-manager[605]: Failed to execute child process "/usr/bin/X" (No such file or directory)
Jan 25 16:09:19 linux140 display-manager[605]: Could not start the X server (your graphical environment) due to an internal error. Please contact your system administrator or check your syslog to diagnose. In the meantime this display will be disabled. Please restart GDM when the problem is corrected.
Jan 25 16:09:19 linux140 display-manager[605]: GdmDisplay: display lasted 0.011674 seconds
Jan 25 16:09:19 linux140 display-manager[605]: GdmLocalDisplayFactory: maximum number of X display failures reached: check X server log for errors
Jan 25 16:11:55 linux140 gdm-launch-environment][1393]: pam_unix(gdm-launch-environment:session): session opened for user gdm by (uid=0)
Jan 25 16:12:16 linux140 gdm-password][1502]: pam_unix(gdm-password:session): session opened for user root by (unknown)(uid=0)
Jan 25 16:12:17 linux140 display-manager[605]: Failed to remove slave program access to the display. Trying to proceed.
linux140:~ # systemctl status display-manager -l
display-manager.service - X Display Manager
Loaded: loaded (/usr/lib/systemd/system/display-manager.service; enabled)
Active: active (running) since Sun 2015-01-25 16:09:19 EST; 4min 29s ago
Process: 605 ExecStart=/usr/lib/X11/display-manager start (code=exited, status=0/SUCCESS)
Main PID: 662 (gdm)
CGroup: /system.slice/display-manager.service
├─ 662 /usr/sbin/gdm --no-console
└─1382 /usr/lib/gdm/gdm-simple-slave --display-id /org/gnome/DisplayManager/Displays/__1_2

Jan 25 16:09:19 linux140 display-manager[605]: GdmDisplay: display lasted 0.011674 seconds
Jan 25 16:09:19 linux140 display-manager[605]: GdmLocalDisplayFactory: maximum number of X display failures reached: check X server log for errors
Jan 25 16:11:55 linux140 gdm-launch-environment][1393]: pam_unix(gdm-launch-environment:session): session opened for user gdm by (uid=0)
Jan 25 16:12:16 linux140 gdm-password][1502]: pam_unix(gdm-password:session): session opened for user root by (unknown)(uid=0)
Jan 25 16:12:17 linux140 display-manager[605]: Failed to remove slave program access to the display. Trying to proceed.
Jan 25 16:13:14 linux140 gdm-launch-environment][1763]: pam_unix(gdm-launch-environment:session): session opened for user gdm by (uid=0)
Jan 25 16:13:37 linux140 gdm-password][1841]: pam_unix(gdm-password:session): session opened for user root by (unknown)(uid=0)
Jan 25 16:13:38 linux140 display-manager[605]: Failed to remove slave program access to the display. Trying to proceed.
Jan 25 16:13:38 linux140 display-manager[605]: GLib-GObject: g_object_ref: assertion 'object->ref_count > 0' failed
Jan 25 16:13:38 linux140 display-manager[605]: GLib-GObject: g_object_unref: assertion 'object->ref_count > 0' failed

mikenash
03-Feb-2015, 23:11
I search for a vnc configuration file that would help manually change the vnc sessions configuration without any success. Are there any configuration files for the multi-display target that would prevent a black screen? What else can be done to obtain information to debug this problem? Suggestions please.

mikenash
10-Feb-2015, 01:17
Still looking for some information, techniques, and assistance to solve this problem. I have been told the the VNC server is vino and not tigervnc. Can anyone verify which VNC server is started at IPL time. Would it be a different from the vnc server that is started from a ssh session? I follow the Suse documentation to turn sharing on but this did not work. Where are the configuration files. With vncconfig I can get the status for AlwaysShared but fails when I attempt to change it. I have tried to use yast and change the network sevices xinetd for xvnc1. This will have an effect on the vnc session but will not accept the AlwaysShared parameter.

malcolmlewis
17-Feb-2015, 17:17
On Tue 10 Feb 2015 12:24:01 AM CST, mikenash wrote:


Still looking for some information, techniques, and assistance to solve
this problem. I have been told the the VNC server is vino and not
tigervnc. Can anyone verify which VNC server is started at IPL time.
Would it be a different from the vnc server that is started from a ssh
session? I follow the Suse documentation to turn sharing on but this did
not work. Where are the configuration files. With vncconfig I can get
the status for AlwaysShared but fails when I attempt to change it. I
have tried to use yast and change the network sevices xinetd for xvnc1.
This will have an effect on the vnc session but will not accept the
AlwaysShared parameter.




Hi
The vino server is for the desktop, tigervnc is still present..

You can check the desktop settings (as set) via dconf-editor from a GUI
or gsettings from the command line on the host;


gsettings list-keys org.gnome.Vino

gsettings get org.gnome.Vino enabled

gsettings set org.gnome.Vino enabled true


Make sure the firewall is down to exclude that, the other option is to
run wireshark to see what's happening traffic wise.

--
Cheers Malcolm °¿° LFCS, SUSE Knowledge Partner (Linux Counter #276890)
SUSE Linux Enterprise Desktop 12 GNOME 3.10.1 Kernel 3.12.36-38-default
If you find this post helpful and are logged into the web interface,
please show your appreciation and click on the star below... Thanks!

mikenash
19-Feb-2015, 19:52
Hello Malcolm, thank you for your reply. I listed the parameters and values but I do not find anything that may help me start a second VNC session.
I am able to this on RedHat Enterprise and on other levels of Suse Enterprise. With other versions of Suse I can go into Applications -> System Tools -> Settings -> Sharing and turn on Screen Sharing and Remote Login. Where are these parameters and values stored? What can I do to gather diagnostics to determine what the problem? What the parameter values are? Where and how to change them?
linux234:~ # gsettings list-recursively org.gnome.Vino
org.gnome.Vino alternative-port uint16 5900
org.gnome.Vino authentication-methods ['vnc']
org.gnome.Vino disable-background false
org.gnome.Vino disable-xdamage false
org.gnome.Vino enabled true
org.gnome.Vino icon-visibility 'client'
org.gnome.Vino lock-screen-on-disconnect false
org.gnome.Vino mailto ''
org.gnome.Vino network-interface ''
org.gnome.Vino notify-on-connect true
org.gnome.Vino prompt-enabled true
org.gnome.Vino require-encryption true
org.gnome.Vino use-alternative-port false
org.gnome.Vino use-upnp false
org.gnome.Vino view-only false
org.gnome.Vino vnc-password 'c2VzMDNwd2Q='