Hi all. I need to run X on a headless server, and I am having a hard time configuring null devices in xorg.conf. Here are the server's vital stats as per the getinfo.sh script on centos.org: http://pastebin.centos.org/33908
When I try to start X: [root@CentOS-55-32-minimal ~]# startx xauth: creating new authority file /root/.serverauth.11196
X Window System Version 7.1.1 Release Date: 12 May 2006 X Protocol Version 11, Revision 0, Release 7.1.1 Build Operating System: Linux 2.6.18-53.el5 i686 Red Hat, Inc. Current Operating System: Linux CentOS-55-32-minimal 2.6.18-194.3.1.el5PAE #1 SMP Thu May 13 13:48:44 EDT 2010 i686 Build Date: 13 May 2010 Build ID: xorg-x11-server 1.1.1-48.76.el5_5.1 Before reporting problems, check http://wiki.x.org to make sure that you have the latest version. Module Loader present Markers: (--) probed, (**) from config file, (==) default setting, (++) from command line, (!!) notice, (II) informational, (WW) warning, (EE) error, (NI) not implemented, (??) unknown. (==) Log file: "/var/log/Xorg.0.log", Time: Mon Jul 26 01:12:22 2010 (==) Using config file: "/etc/X11/xorg.conf" (EE) NV(0): No valid initial configuration found (EE) Screen(s) found, but none have a usable configuration.
Fatal server error: no screens found XIO: fatal IO error 104 (Connection reset by peer) on X server ":0.0" after 0 requests (0 known processed) with 0 events remaining. [root@CentOS-55-32-minimal ~]#
Right now xorg.conf is stock, I have removed all my failed experiments. Should I post the logfiles? Note that my goal is to start X, then ssh in and run Firefox remotely from a Fedora desktop. The server itself has no monitor.
Thanks in advance for any advice.
On 25 July 2010 16:15, Dotan Cohen dotancohen@gmail.com wrote:
experiments. Should I post the logfiles? Note that my goal is to start X, then ssh in and run Firefox remotely from a Fedora desktop. The server itself has no monitor.
I'm not sure what you are trying to do. Using VNC server or ssh with X11 tunneling (-X or -Y) would make more sense. You don't need X itself running for either of these.
On Sun, Jul 25, 2010 at 18:26, Hakan Koseoglu hakan@koseoglu.org wrote:
I'm not sure what you are trying to do. Using VNC server or ssh with X11 tunneling (-X or -Y) would make more sense. You don't need X itself running for either of these.
Yes, my intention is to ssh in then run the app like this: local$ ssh -X user@remote remote$ firefox
However, when I do this I get no response (no firefox window opens, no terminal output), even after several minutes. I figured that was because X is not running.
Dotan,
On 25 July 2010 16:32, Dotan Cohen dotancohen@gmail.com wrote:
However, when I do this I get no response (no firefox window opens, no terminal output), even after several minutes. I figured that was because X is not running.
That's not the reason. You don't run X on the server for such purposes. You already run it on your own PC. In such cases the server runs on your PC, the client is the app you are running. I know it sounds backward but that's the case. Are you sure you have enough bandwidth? Try running something simple like xterm. Also X11 forwarding might have been turned off in sshd_config.
On Sun, Jul 25, 2010 at 18:38, Hakan Koseoglu hakan@koseoglu.org wrote:
Dotan,
On 25 July 2010 16:32, Dotan Cohen dotancohen@gmail.com wrote:
However, when I do this I get no response (no firefox window opens, no terminal output), even after several minutes. I figured that was because X is not running.
That's not the reason. You don't run X on the server for such purposes. You already run it on your own PC. In such cases the server runs on your PC, the client is the app you are running. I know it sounds backward but that's the case.
Actually, I do understand that unusual server/client relationship. But I thought that X had to be running on the remote machine too. I am happily corrected!
Are you sure you have enough bandwidth? Try running something simple like xterm. Also X11 forwarding might have been turned off in sshd_config.
I don't. After 15 minutes the square of the supposed Firefox window came up. That's painful! But therein lies the problem.
Thanks.
On Sun, Jul 25, 2010 at 07:23:03PM +0300, Dotan Cohen wrote:
I don't. After 15 minutes the square of the supposed Firefox window came up. That's painful! But therein lies the problem.
Which shows it's working... but painfully slowly. Bandwidth and especially latency is killing you.
FreeNX is designed to work around this by reducing the number of round-trips needed (amongst other things).
On Sun, Jul 25, 2010 at 19:35, Stephen Harris lists@spuddy.org wrote:
Which shows it's working... but painfully slowly. Bandwidth and especially latency is killing you.
Other than getting a new ISP, is there anything that I can do about the latency?
FreeNX is designed to work around this by reducing the number of round-trips needed (amongst other things).
Great!
On Sun, Jul 25, 2010 at 08:46:08PM +0300, Dotan Cohen wrote:
On Sun, Jul 25, 2010 at 19:35, Stephen Harris lists@spuddy.org wrote:
Which shows it's working... but painfully slowly. ??Bandwidth and especially latency is killing you.
Other than getting a new ISP, is there anything that I can do about the latency?
Even another ISP may not help so much. I have Verizon FIOS and am based on the East Coast. There's a 92ms delay to reach my linode, in Fremont. Any message the X client sends to the server and then waits for a reply would have approx 200ms round trip time. I doesn't take long before these message delays add up to a real long delay.
Even my local East Coast Panix v-colo has a 15ms delay; that's a lot smaller but it still adds to the time it takes to open an application; especially one as complicated as firefox which may make thousands of requests.
Hence FreeNX which, effectively, runs an X server on your remote machine and sends screen data back to your local machine. In this case the round trip times are massively reduced to effectively "local machine" speeds.
Stephen Harris wrote:
Even another ISP may not help so much. I have Verizon FIOS and am based on the East Coast. There's a 92ms delay to reach my linode, in Fremont. Any message the X client sends to the server and then waits for a reply would have approx 200ms round trip time. I doesn't take long before these message delays add up to a real long delay.
Even my local East Coast Panix v-colo has a 15ms delay; that's a lot smaller but it still adds to the time it takes to open an application; especially one as complicated as firefox which may make thousands of requests.
Hence FreeNX which, effectively, runs an X server on your remote machine and sends screen data back to your local machine. In this case the round trip times are massively reduced to effectively "local machine" speeds.
Are there any advantages to running FreeNX over vncserver? Does it perform better?
Nataraj
From: Nataraj incoming-centos@rjl.com
Are there any advantages to running FreeNX over vncserver? Does it perform better?
Unless I am mistaken: VNC traffic is bitmap (whole screen or part of the screen, optionaly compressed) transfered at each refresh. FreeNX is compressed/cached XWindow traffic. I think, although there are bitmaps in XWindow too, you could almost think of it as bitmap (heavy) vs vectorial (light). http://en.wikipedia.org/wiki/NX_technology
JD
Nataraj wrote:
Stephen Harris wrote:
Even another ISP may not help so much. I have Verizon FIOS and am based on the East Coast. There's a 92ms delay to reach my linode, in Fremont. Any message the X client sends to the server and then waits for a reply would have approx 200ms round trip time. I doesn't take long before these message delays add up to a real long delay.
Even my local East Coast Panix v-colo has a 15ms delay; that's a lot smaller but it still adds to the time it takes to open an application; especially one as complicated as firefox which may make thousands of requests.
Hence FreeNX which, effectively, runs an X server on your remote machine and sends screen data back to your local machine. In this case the round trip times are massively reduced to effectively "local machine" speeds.
Are there any advantages to running FreeNX over vncserver? Does it perform better?
Yes, in some cases it it much better. Vnc just sends bitmaps but FreeNX uses X protocol with proxy/caching to improve it. Plus it runs over ssh by default and automatically sets up sessions per connection.
Dotan Cohen wrote:
On Sun, Jul 25, 2010 at 19:35, Stephen Harris lists@spuddy.org wrote:
Which shows it's working... but painfully slowly. Bandwidth and especially latency is killing you.
Other than getting a new ISP, is there anything that I can do about the latency?
I can smoothly run X over the Internet to the servers I look after only because I myself have a 10mbit/10mbit connection and the servers are either on 50mbit or 100mbit connections but that is not true for all X clients. X can require an incredible amount of bandwidth to be smooth.
Chan Chung Hang Christopher wrote:
Dotan Cohen wrote:
On Sun, Jul 25, 2010 at 19:35, Stephen Harris lists@spuddy.org wrote:
Which shows it's working... but painfully slowly. Bandwidth and especially latency is killing you.
Other than getting a new ISP, is there anything that I can do about the latency?
I can smoothly run X over the Internet to the servers I look after only because I myself have a 10mbit/10mbit connection and the servers are either on 50mbit or 100mbit connections but that is not true for all X clients. X can require an incredible amount of bandwidth to be smooth.
The bandwidth isn't so much a problem with X as latency - the protocol does a lot of synchronous handshakes that wait for a round trip before continuing to the next step. NX is much better because there is a proxy display to avoid waiting for the remote handshake with caching on both ends.
At Mon, 26 Jul 2010 07:17:45 +0800 CentOS mailing list centos@centos.org wrote:
Dotan Cohen wrote:
On Sun, Jul 25, 2010 at 19:35, Stephen Harris lists@spuddy.org wrote:
Which shows it's working... but painfully slowly. Bandwidth and especially latency is killing you.
Other than getting a new ISP, is there anything that I can do about the latency?
I can smoothly run X over the Internet to the servers I look after only because I myself have a 10mbit/10mbit connection and the servers are either on 50mbit or 100mbit connections but that is not true for all X clients. X can require an incredible amount of bandwidth to be smooth.
About the *only* X11 client that works well over *dial-up* (or other low-speed and/or high-latency connections) is the old XAW-flavored xterm (I use it all of the time). For pretty much all other X11 clients, you really need a local LAN connection (eg 10BaseT or better). This is partitularly true for any sort of non-trivial GUI (like a graphical web browser for example).
X11 is not really designed for truely 'remote' usage. X11's idea of 'remote' is like 'down the hall' or 'across the room' or 'down in the basement server room of the building your office workstation is in'.
Unless of course you have a 100mbit fiberoptic link to the Internet backbone. :-)
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Dotan Cohen wrote:
On Sun, Jul 25, 2010 at 18:26, Hakan Koseoglu hakan@koseoglu.org wrote:
I'm not sure what you are trying to do. Using VNC server or ssh with X11 tunneling (-X or -Y) would make more sense. You don't need X itself running for either of these.
Yes, my intention is to ssh in then run the app like this: local$ ssh -X user@remote remote$ firefox
However, when I do this I get no response (no firefox window opens, no terminal output), even after several minutes. I figured that was because X is not running.
I think you need to use -Y instead of -X these days but I've never understood which apps care. Also, firefox is unusual in that if it is already running for a user it will try to tell the running copy to open a new window in its existing context instead of opening a new one that can be forwarded (but you'd only see that if you had X running elsewhere).
What you are trying should work without running X at the console, but you might like the freenx/NX client even better. That gives you a complete remote X desktop with very good performance that you can disconnect and reconnect with everything still running. See www.nomachine.com for the client (linux/windows/mac) details but you can get freenx from the epel repo.
On Sun, Jul 25, 2010 at 9:10 AM, Les Mikesell lesmikesell@gmail.com wrote:
What you are trying should work without running X at the console, but you might like the freenx/NX client even better. That gives you a complete remote X desktop with very good performance that you can disconnect and reconnect with everything still running. See www.nomachine.com for the client (linux/windows/mac) details but you can get freenx from the epel repo.
I would also recommend NX. CentOS supplies freenx/nx, no need to go to EPEL. :-)
Please follow the instructions here:
http://wiki.centos.org/HowTos/FreeNX
Akemi
On Sun, Jul 25, 2010 at 19:14, Akemi Yagi amyagi@gmail.com wrote:
On Sun, Jul 25, 2010 at 9:10 AM, Les Mikesell lesmikesell@gmail.com wrote:
What you are trying should work without running X at the console, but you might like the freenx/NX client even better. That gives you a complete remote X desktop with very good performance that you can disconnect and reconnect with everything still running. See www.nomachine.com for the client (linux/windows/mac) details but you can get freenx from the epel repo.
I would also recommend NX. CentOS supplies freenx/nx, no need to go to EPEL. :-)
Please follow the instructions here:
Thanks for the suggestion, I will give it a try. I have heard of FreeNX, but never used it.
Have a great week!
Akemi Yagi wrote:
On Sun, Jul 25, 2010 at 9:10 AM, Les Mikesell lesmikesell@gmail.com wrote:
What you are trying should work without running X at the console, but you might like the freenx/NX client even better. That gives you a complete remote X desktop with very good performance that you can disconnect and reconnect with everything still running. See www.nomachine.com for the client (linux/windows/mac) details but you can get freenx from the epel repo.
I would also recommend NX. CentOS supplies freenx/nx, no need to go to EPEL. :-)
You need to be somewhat careful these days about things that came from centos-testing or extras as some now also appear in epel with the same names and version number that aren't likely to be coordinated. I haven't seen anything actually break from this yet but have been surprised to see things originally installed from CentOS updating from EPEL.
On Sun, Jul 25, 2010 at 9:42 AM, Les Mikesell lesmikesell@gmail.com wrote:
You need to be somewhat careful these days about things that came from centos-testing or extras as some now also appear in epel with the same names and version number that aren't likely to be coordinated. I haven't seen anything actually break from this yet but have been surprised to see things originally installed from CentOS updating from EPEL.
Good point. While centos-testing and centosplus repos are disabled by default, extras is shipped enabled. So, any 3rd party repo (including EPEL) must be used with proper setup (priority plugin, include/exclude lines, etc). I have added a note to the EPEL section at:
http://wiki.centos.org/AdditionalResources/Repositories
EPEL is generally known to not overwrite distro files, but when it starts showing conflicts with the CentOS extras repo, that needs an additional note.
Akemi
Akemi Yagi wrote:
On Sun, Jul 25, 2010 at 9:42 AM, Les Mikesell lesmikesell@gmail.com wrote:
You need to be somewhat careful these days about things that came from centos-testing or extras as some now also appear in epel with the same names and version number that aren't likely to be coordinated. I haven't seen anything actually break from this yet but have been surprised to see things originally installed from CentOS updating from EPEL.
Good point. While centos-testing and centosplus repos are disabled by default, extras is shipped enabled. So, any 3rd party repo (including EPEL) must be used with proper setup (priority plugin, include/exclude lines, etc). I have added a note to the EPEL section at:
http://wiki.centos.org/AdditionalResources/Repositories
EPEL is generally known to not overwrite distro files, but when it starts showing conflicts with the CentOS extras repo, that needs an additional note.
I think the point is that CentOS isn't 'the distro' that epel doesn't overwrite. And it really makes more sense for most additional content to be maintained in epel where it is available and compatible for RHEL and Scientific Linux users as well as CentOS. And since you are fairly likely to need at least some of the extensive content from epel, you might as well treat the centos plus/extras/testing repos as the 3rd party addons that they are, particularly in light of the frequent comments here that their only priority is compatibility with upstream.
On Sun, Jul 25, 2010 at 20:29, Les Mikesell lesmikesell@gmail.com wrote:
Akemi Yagi wrote:
On Sun, Jul 25, 2010 at 9:42 AM, Les Mikesell lesmikesell@gmail.com wrote:
You need to be somewhat careful these days about things that came from centos-testing or extras as some now also appear in epel with the same names and version number that aren't likely to be coordinated. I haven't seen anything actually break from this yet but have been surprised to see things originally installed from CentOS updating from EPEL.
Good point. While centos-testing and centosplus repos are disabled by default, extras is shipped enabled. So, any 3rd party repo (including EPEL) must be used with proper setup (priority plugin, include/exclude lines, etc). I have added a note to the EPEL section at:
http://wiki.centos.org/AdditionalResources/Repositories
EPEL is generally known to not overwrite distro files, but when it starts showing conflicts with the CentOS extras repo, that needs an additional note.
I think the point is that CentOS isn't 'the distro' that epel doesn't overwrite. And it really makes more sense for most additional content to be maintained in epel where it is available and compatible for RHEL and Scientific Linux users as well as CentOS. And since you are fairly likely to need at least some of the extensive content from epel, you might as well treat the centos plus/extras/testing repos as the 3rd party addons that they are, particularly in light of the frequent comments here that their only priority is compatibility with upstream.
Ooff, that sounds familiar. I jumped ship from Fedora around FC6, one of the reasons was constant dependency hell. I don't remember the details, but I really needed packages from both the Livna and Dag camps.
Dotan Cohen wrote:
EPEL is generally known to not overwrite distro files, but when it starts showing conflicts with the CentOS extras repo, that needs an additional note.
I think the point is that CentOS isn't 'the distro' that epel doesn't overwrite. And it really makes more sense for most additional content to be maintained in epel where it is available and compatible for RHEL and Scientific Linux users as well as CentOS. And since you are fairly likely to need at least some of the extensive content from epel, you might as well treat the centos plus/extras/testing repos as the 3rd party addons that they are, particularly in light of the frequent comments here that their only priority is compatibility with upstream.
Ooff, that sounds familiar. I jumped ship from Fedora around FC6, one of the reasons was constant dependency hell. I don't remember the details, but I really needed packages from both the Livna and Dag camps.
EPEL is "better" in that they make an effort to never replace base packages, but they consider RHEL as the base. You are usually safe leaving epel enabled for updates - but for a few things you may want newer packages from other repos where you have to be more careful.
Am 25.07.2010 17:15, schrieb Dotan Cohen:
Note that my goal is to start X, then ssh in and run Firefox remotely from a Fedora desktop. The server itself has no monitor.
Thanks in advance for any advice.
For that you do not need an X server on the remote machine all you need is X11 Forwarding in SSH. It needs to be enabled on the SSH Server (X11Forwarding option) and on the SSH client (command line options -Y or -X)
You only need to run an X server on the remote machine if you want to do XDMCP
+C
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Akemi Yagi -
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Chan Chung Hang Christopher -
Christoph Maser -
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Hakan Koseoglu -
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Robert Heller -
Stephen Harris