Archive for the ‘CentOS’ Category

CentOS Administrator re-appears after the long dis-appearance…

August 3, 2009

Have you been using CentOS? If you have been using it then be happy, the Administrator has re-appeared and had meeting with all developers. If you decided to switch from CentOS after his disappearance then you should give it a second thought now. As CentOS has announced that the development will continue as it was and as the Administrator has reappeared the working agreement has been reached among the developers to resolve the remaining issues. The announcement also mentioned there should be no impact on CentOS users.

The copy of Open Letter to Lance Davic,

Note: The CentOS Development team had a normal meeting today and Lance Davis was in attendance. In the meeting a majority of issues were resolved right away and a working agreement was reached with deadlines for any unresolved issues. There should be no impact to any CentOS users moving forward.

July 30, 2009 04:39 UTC

This is an Open Letter to Lance Davis from fellow CentOS Developers

This is an Open Letter to Lance Davis from fellow CentOS Developers

It is regrettable that we are forced to send this letter but we are left with no other options. For some time now we have been attempting to resolve these problems:

You seem to have crawled into a hole … and this is not acceptable.

You have long promised a statement of CentOS project funds; to this date this has not appeared.

You hold sole control of the domain with no deputy; this is not proper.

You have, it seems, sole ‘Founders’ rights in the IRC channels with no deputy ; this is not proper.

When I (Russ) try to call the phone numbers for UK Linux, and for you individually, I get a telco intercept ‘Lines are temporarily busy’ for the last two weeks. Finally yesterday, a voicemail in your voice picked up, and I left a message urgently requesting a reply. Karanbir also reports calling and leaving messages without your reply.

Please do not kill CentOS through your fear of shared management of the project.

Clearly the project dies if all the developers walk away.

Please contact me, or any other signer of this letter at once, to arrange for the required information to keep the project alive at the ‘’ domain.


Russ Herrold
Ralph Angenendt
Karanbir Singh
Jim Perrin
Donavan Nelson
Tim Verhoeven
Tru Huynh
Johnny Hughes

So System Admins and Linux users, best of luck tweaking your CentOS servers. I hope CentOS will stay with us and will not go away as promised by the developers.


What to do if your Amazon EC2 instance becomes unresponsive?

October 5, 2008

I have been very badly hurt by this, as our programmers were very actively working on PHP application and all of a sudden yesterday my Aamzon EC2 instance stopped responding to all TCP/UDP communication. I tried everything including ec2-reboot but nothing worked out, there were few major changes in the code which were not backed up and I fear losing them.

The distribution was CentOS 5 and I was running apache and ha-proxy on the instance, ha-proxy was running for a possible new instance launch to accommodate the load. Thanks that I had MySQL db on a different instance. The instance was launched using RightScale (because my client wanted it). The RightScale guys had some code changes in their Dashboard but I doubt that will effect the running instance.

I am not going to terminate the instance until there is the a last ray of hope. I am posting this question to some major forums including slashdot and others in the hope that I might get some help. So, if any of you have ever faced this situation, how you dealt with it? How you recovered your data from EC2 instance? And how did you get back you instance to respond to TCP communication?

UPDATE: That was a hardware fault and after sometime the instance came back to normal without losing anything. 🙂 Thanks everyone who helped me during that time.

How to view actual physical memory available on xen host

July 19, 2008

When I was new on xen I had this very problem, that I was not able to figure out what is the actual amount of physical ram on xen host i.e Dom0. So sharing this little tip here for newbies that might be starting.

use “xm top” command to find out the actual physical ram.

Hope this will be helpful for someone.

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How You can create xen VM without installation

February 21, 2008
  1. Download the CentOS 5.1 image from jailtime.
  2. At the time of writing this howto the current image file name is: centos.5-1.20080125.img.tar.bz2

  3. Untar the image:
  4. # tar -xjf centos.5-1.20080125.img.tar.bz2

  5. Create directories under /mnt to mount image your downloaded from jailtime and in our case lvm parition.
  6. # mkdir /mnt/img
    # mkdir /mnt/vm

  7. Mount jailtime image and lvm partition image.
  8. # mount -o loop centos.5-1.img /mnt/img
    # mount /dev/vg/ComC /mnt/vm

  9. Copy the image files to our VM image i.e on lvm parition.
  10. # cp -a /mnt/img/* /mnt/vm/

  11. Configure IP for domU. I don’t think I need to explain this step.
  12. cat /mnt/vm/etc/sysconfig/network-scripts/ifcfg-eth0


  13. Configure domU hostname.
  14. [root@aag ~]# cat /mnt/vm/etc/sysconfig/network


  15. For me the xm console never worked until I have used this line in /mnt/vm/etc/inittab, I hope you know where to put following line in /mnt/vm/etc/inittab, other wise learn about inittab first please.
  16. 1:2345:respawn:/sbin/mingetty console

  17. root logins are not allowed on default jailtime image, so if you need them you can enable them too, or if you change your SSH port to something unusual you can do that too in /mnt/vm/etc/ssh/sshd_config change following:
  18. Port 2023

    PermitRootLogin yes

  19. Unmount both images.
  20. # umount /mnt/img /mnt/vm

  21. Create initrd image for your domU
  22. # mkinitrd /boot/xen-guest-initrd `uname -r` --with xenblk --with xennet --preload xenblk --preload xennet

  23. Create a xen config file, as I was using LVM partition so my config file will look bit different.
  24. My domU config file looks like following:
    [root@aag xen]# cat complay.cfg

    kernel = “/boot/xen-vm-kernel”
    ramdisk = “/boot/xen-guest-initrd”
    name = “complay”
    memory = “128”
    disk = [ ‘phy:vg/ComC-swap,sda2,w’, ‘phy:vg/ComC,sda1,w’ ]
    vif = [ ‘mac=00:14:d1:3e:F9:f1’, ]
    root = “/dev/sda1 rw”
    on_reboot = ‘restart’
    on_crash = ‘destroy’

  25. Start your domU
  26. # xm create -c /etc/xen/complay.cfg

  27. You will see a nice login prompt like following:
  28. CentOS release 5 (Final)
    Kernel 2.6.18-8.1.14.el5xen on an i686

    complay login:

  29. Login as root, default root password for jailtime image is “password”
  30. Change your root password first 😉
  31. Enter nameservers in /etc/resolv.conf
  32. Now this small CentOS 5.1 image likes many usefult softwares, few of which I really like and need I will install here. If you don’t find your favourite software you know how to install it right?
  33. # yum -y install logwatch postfix vim-enhancd iptables anacron

  34. Now your VM is ready to be used.

Possible Errors

If you get following Error:

Error: destroyDevice() takes exactly 3 arguments (2 given)

Make sure you have unmounted your image: umount /mnt/vm

Happy Sysadmin Day!

July 27, 2007

SysAdmin Day
Happy Sysadmin Day to all Sysadmins out there.

So, Say thanks to your SysAdmin and if you don’t do it on 27th, you can do it on later days too. They will really appreciate it. You criticize them and call them up for you complains and problems the whole year, but this is the day to appreciate them for their work. Its always sysadmins who make programmers bad and buggy code work on systems and submit bug reports to them so they can fix it.

For more information about this day see:
System Administrator Appreciation Day
System Administrator Appreciation Day – Wikipedia

CentOS 5: Bad Expereinces

July 1, 2007

Finally after many days I am able to get some time out for my little so called blog :). I am gonna write about the experience or bad experience I had today with CentOS 5. Today I thought that I should give CentOS 5 a try. The install process was almost the same as before.

The first bad impression of CentOS 5 was the software was still the same old software i.e FireFox 1.5.x and Thunderbird 1.5.x. I don’t know the reason why these are not upgraded to the new series of 2.x, but these 2 softwares are my mostly used softwares and I can’t go back to 1.5 series without having a good strong reason. Maybe CentOS 5 borrowed this from RedHat 5.

The other very strange problem from the layman point was during installation I thought I should install Virtualization packages and should give it a try. After installation I found that CentOS 5 is somewhat slower on my home machine with 1G of Physical Ram and 2.6Ghz Intel Processor, I thought I should remove the Virtualization packages from my home machine and will try it on some other more powerfull machine. I went to Add/Remove Software and de-selected Virtualization option. The uninstallation was successfull, after uninstallation I thought I should reboot the machine so it will start from the normal kernel instead of the Xen kernel, because when you select Virtualizaiton during installation your CentOS 5 will automatically boot with Xen Kernel (no choice like SLES to boot to the normal or Xen Kernel).

I rebooted the machine and I was surprised GRUB spitted an error on the screen saying it can’t find the xen kernel.

I think CentOS 4.4 still gets my vote for being more stable and reliable then CentOS 5. I wonder about RedHat 5 do they have the same problems too. I Love CentOS 4.4 🙂

Note: The above all comments are from an end user point of view by an individual and does not represent the comments of any company or any other person except me (Hameedullah Khan).