Chrome 28 and newer for CentOS 6

Officially Google no longer support Chrome for CentOS 6 (ref). The recommendation (for now) is to either switch to Firefox or Chromium. I decided to go with the second option.

Obtain the YUM repository settings here: chromium-el6 repo.

First uninstall Google Chrome

# sudo yum remove google-chrome

To install:

# sudo wget -O /etc/yum.repos.d/chromium-el6.repo
# sudo yum install chromium

Do not launch Chromium immediately, if you want your Chrome settings to transfer over do the following:

# mv ~/.config/google-chrome ~/.config/chromium

(Alternatively you can copy cp -a or link ln -s)

If you want the Google Chrome PDF and/or Flash plugins (I did), then the extra step(s) are required:

# cd /tmp
# wget
# sh
# cd /tmp
# wget
# sh

I am not happy with Google’s lack of support but I have become dependent on Chrome sync across all my computers and devices. I hope that Google changes/updates their process or that RHEL7 releases soon.


Yum Groups

The Fedora 18 installer does not allow single package installations, instead it prefers to install by package groups. You can also install groups after completing installation. This is especially useful since you can only select one Desktop Environment at installation. Alternatively, to have faster installations, select as few groups as possible and then only install the ones you need later.

This is just a quick note on how yum can install by groups instead of by individual packages.

To see all of the available groups run:

$ yum groups list

Example (abbreviated) output:

Available Environment Groups:
   GNOME Desktop
   KDE Plasma Workspaces
   Xfce Desktop
Available Groups:
   Authoring and Publishing
   Books and Guides
   Development Tools

Note: Quotes below are not needed when the group name is a single word, however if the group name has spaces make sure you use quotes.

Pick a group above, example Authoring and Publishing.
To see what packages the group includes, run:

$ yum groups info 'Authoring and Publishing'

To install the entire group, run:

$ sudo yum groups install 'Authoring and Publishing'

To remove the group, run:

$ sudo yum groups remove 'Authoring and Publishing'

Note: Generally removing a group is not recommended, you may remove dependencies which may make your system unusable.

Firefox 4 for Fedora 14

Wow! That’s a lot of F’s!

Courtesy of Tom ‘spot’ Calloway, install Firefox 4 on Fedora 14 (or Fedora 13):

# su -c 'wget -P /etc/yum.repos.d/'
# su -c 'yum install firefox4'

To run:

# firefox4 &

In Gnome: System > Preferences > Preferred Applications
Change ‘Web Browser’ to Custom, and for Command: firefox4 %s

To remove Firefox 3.6:

# su -c 'yum remove firefox'


Boot Failure When Fedora 12 Grub Installs to non-MBR Partition

I prefer to keep Windows on the MBR. So I install grub to a separate partition. I then allow the Windows Loader to chainload grub (example).

I noticed a problem with the Fedora 12 Anaconda Installer. If I chose to install grub to the First sector of boot partition instead of the MBR, I get an un-bootable system.

It is easy to see the problem if you compare fdisk output. (I reduced the output for clarity)

Before I installed Fedora 12 32-bit to /dev/sda10

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        2089    16779861    7  HPFS/NTFS
/dev/sda4            6268       36479   242677890    f  W95 Ext'd (LBA)
/dev/sda10          23762       25589    14683378+  83  Linux
/dev/sda14          34076       36192    17004771   83  Linux
/dev/sda15          36193       36478     2297263+  82  Linux swap / Solaris

After I installed Fedora 12:

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1        2089    16779861    7  HPFS/NTFS
/dev/sda4            6268       36479   242677890    f  W95 Ext'd (LBA)
/dev/sda10  *       23762       25589    14683378+  83  Linux
/dev/sda14          34076       36192    17004771   83  Linux
/dev/sda15          36193       36478     2297263+  82  Linux swap / Solaris

The boot flag is set to the wrong partition.

To fix this problem

Just boot with a CD/DVD, choose “Rescue” mode and run fdisk at the shell to change the boot flag. If you need more help, details follow:

  1. Boot with the system using your Fedora DVD or CD#1.
  2. Select “Rescue installed system”. (Select the proper settings, networking is not necessary)
    At the “Rescue” screen, you can “Skip” the mounting of your installed system.
    At the “First Aid Kit quickstart” menu, Select “shell”.
  3. At the shell prompt, use fdisk (BE CAREFUL!)
    bash-4.0# fdisk /dev/sda
    Command (m for help): a        (toggle bootable flag)
    Partition number (1-15): 10    (the partition you installed Fedora)
    Command (m for help): a        (command needs to be run twice)
    Partition number (1-15): 1     (the partition with MBR)
    Command (m for help): p        (verify everything looks correct)
    Command (m for help): w        (write table to disk and exit)
    The partition table has been altered!
    Calling ioctl() to re-read partition table.
    Syncing disk.
  4. Reboot.

I doubt this will affect many people since most people choose to install Fedora directly to the MBR. However I am reporting here in case someone else might find this useful. I noticed this a few days ago on Fedora 12-Beta 64-bit, but I had been too busy to check the bug reports. Will do that soon.

If you run into this problem (or similar) please leave a comment or contact me.

UPDATE: Should be fixed for Fedora 13. Bug 533658

NT Bootloader Update

This post really has no purpose other than just a snapshot for me.

My current c:\boot.ini:

[boot loader]
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINNT="Microsoft Windows 2000 Professional" /noexecute=optin /fastdetect
multi(0)disk(0)rdisk(0)partition(3)\WINDOWS="Microsoft Windows XP Professional" /noexecute=optin /fastdetect
c:\linux1.bin="[ sda7]  Fedora 11   (32)  [06/2009]"
c:\linux2.bin="[ sda8]  Fedora  9   (32)  [05/2008]"
c:\linux3.bin="[ sda9]  Fedora 11   (64)  [06/2009]"
c:\linux4.bin="[sda10]  Fedora 10   (32)  [11/2008]"
c:\linux5.bin="[sda11]  CentOS 5.3  (32)  [07/2009]"
c:\linux6.bin="[sda12]  OpenSuSe 11 (32)  [10/2008]"

That F9 and F10 will be replaced with F12 (beta at the moment). I might even drop in a Ubuntu Karmic Koala in there somewhere (if I get the time).

I know, I really need to retire my Windows 2000!
I think I also need to repartition that system!

Or best idea: I should get a new computer that supports KVM and switch to virtualization instead of this octuple-boot nightmare !!!

Time to start saving …

Default Xorg Resolution

Recent versions of Linux and the Xorg X-Windows system have been engineered to require very little configuration settings to properly detect graphics options and display resolutions. In most cases graphics should “just work”.

The Xorg system stores all its configuration options in the file: xorg.conf. Many distributions including Fedora and CentOS keep this file in the /etc/X11/ directory. In the past this file would contain a great deal of information that was not easy to setup. However as of recent releases, this file is not required for graphics to work correctly. Both Fedora and CentOS will provide a very minimal xorg.conf file if required.

Typically the proper resolution for your display will be detected at run time. While this is great for most users, it often leads to strange resolutions or blank screens depending on your monitor or LCD screen.

EDIT: If you have NO file at all, on the Fedora wiki is: How to create xorg.conf. This works for both Fedora and CentOS.
There are two solutions if you have no xorg.conf. As ‘root’ run either of the following:

# yum install system-config-display
# system-config-display --noui


# yum install xorg-x11-server-Xorg
# Xorg -configure
# cp /etc/X11/xorg.conf

Whenever I install Fedora or CentOS with the X-server, I typically edit /etc/X11/xorg.conf and add the following Section (or at least the missing parts):

Section "Screen"
        Identifier "Screen0"
        Device     "Videocard0"
        DefaultDepth     24
        Subsection "Display"
                Viewport   0 0
                Depth     24
                Modes     "1024x768"

The Modes line will control the resolution. You should put the proper resolution for your display. You can also add mutiple modes if you monitor supports it. For example:

Modes     "1280x1024" "1024x768" "800x600"

If you have an LCD and Xorg does not properly detect the resolution, set the mode to the maximum resolution your LCD supports. If you have a standard CRT monitor that Xorg detects higher resolutions (with poor refresh rates) set the mode to the resolution you are comfortable. Also, if you have a CRT you can set multiple modes, then using either Gnome or KDE you can pick a resolution you prefer.

Note: This does NOT apply to everyone (most people will find the defaults correct), however many people have reported that setting a fixed resolution is helpful. Especially for some LCD’s which just seem to go blank.

For more information run man xorg.conf

Edit: 11/23/2009

All-In-One Configuration Tools

As I mentioned previously, I run many sites on my web server. Yesterday I decided to clean up some sites that their owners had neglected or not used. One such site was running Apache Tomcat Java Server, which I did not care to leave running.

Now I, like many users of commercial hosting plans, pay for cPanel/WHM which includes a myriad of options/configurations/settings to do almost everything on the server. Back in 2007, I had used the cPanel Addon to install Tomcat. It was an incredibly easy “1-click Install”. I never checked, but I just assumed it worked. Similarly I thought it would be just as easy to uninstall Tomcat. I clicked “Uninstall” and all went well and I didn’t see any immediate problems. Or so I thought …

Last night the Apache Webserver failed. I did not realize till this morning (6 hours later). After some digging I found that it was because Apache could not find some Tomcat/Java module. So much for a proper uninstall. I did not have time to debug the issue, so what did I do? I simply re-installed Tomcat. I just could not afford any more downtime! … I know, I know: Shame on me!

This incident is like many commonly seen in the Linux world: An all-in-one graphical configuration tool can do wonders, but somewhere due to interaction between components it can causes all sorts of unforeseen problems. The root problem here is that it is incredibly difficult to know all the intricacies and nuances for administrating multiple software systems. Add to that the occasional need to manually edit config files, and you create an unmanageable mess.

Do you remember linuxconf? … Back in the day (pre-2002) Red Hat included a configuration tool called linuxconf which could manage multiple system options using a variety of graphical and non-graphical interfaces. While this worked wonders for novices performing simple tasks (mounting disk partitions, adding users, setting network addresses), it caused all sorts of issues for more complex services (web server, mail server, samba). Unfortunately at that time, there were very few complete comprehensive tools for configuring complex servers. Users who got burned using linuxconf, eventually learned that the only guaranteed way to setup things was to read man pages and documentation, and then editing config files manually.

Redhat did eventually abandon linuxconf with RH8.0. And while many users did complain, ultimately it was a smart decision. Software projects cannot be held accountable if some 3rd-party tool mangled their config files. Even more importantly, how can someone be certain the tool made the change they requested without looking at the config output? You can’t.

Sadly even though I expected cPanel to do its job (considering it is not free), I should have been more careful on a live production server. While I’m not saying that every single “all-in-one” tool is a failure, I am saying that trusting any tool without validation is a very poor choice.

Command Line DVD Burning

When I built my server, I only used a CD-RW/DVD-ROM combination drive. Whenever I remotely downloaded a ISO using wget or bittorrent, I would have to copy the 2-4GB file(s) from my server to either my desktop or laptop. I finally caved, and bought a DVD-RW drive for my server (even though it will get minimal usage).

(This was all on my CentOS 5 server, I executed these commands entirely remotely. )

After I installed the new drive, I ran dmesg to check how it was detected:

[mirandam@atlas ~]$ dmesg | grep DVD
hda: HP DVD Writer 1140d, ATAPI CD/DVD-ROM drive
hda: ATAPI 12X DVD-ROM DVD-R-RAM CD-R/RW drive, 2048kB Cache, UDMA(66)

The device is /dev/hda, which will be linked to the DVD device in /dev:

[mirandam@atlas ~]$ ls -l /dev | grep dvd
lrwxrwxrwx 1 root root         3 Aug 19 19:44 dvd -> hda
lrwxrwxrwx 1 root root         3 Aug 19 19:44 dvd-hda -> hda
lrwxrwxrwx 1 root root         3 Aug 19 19:44 dvdrw -> hda
lrwxrwxrwx 1 root root         3 Aug 19 19:44 dvdrw-hda -> hda
lrwxrwxrwx 1 root root         3 Aug 19 19:44 dvdwriter -> hda
lrwxrwxrwx 1 root root         3 Aug 19 19:44 dvdwriter-hda -> hda

Necessary Software

In order to work with DVD writing, you should have the dvd+rw-tools package installed. This will most likely be installed if you have Gnome or a CD/DVD app such as K3b. If not install via yum:

# yum install dvd+rw-tools

I wanted to erase a DVD+RW.

I had a junk DVD+RW (Memorex) laying around that I wanted quickly deleted. I used the dvd+rw-format command (it took less than 30 seconds):

[mirandam@atlas ~]$ sudo dvd+rw-format -force /dev/dvd
* BD/DVD+RW/-RAM format utility by <appro>, version 7.0.
* 4.7GB DVD+RW media detected.
* formatting 92.3\

I wanted to burn a downloaded ISO file onto the DVD+RW.

I used the growisofs command. I tried using sudo but it refused, so logged in directly as root.

[mirandam@atlas ISO]$ su -
[root@atlas ~]# cd ~mirandam/ISO/

[root@atlas ISO]# growisofs -dvd-compat -Z /dev/dvd=DVD_Image.iso -speed 2
Executing 'builtin_dd if=DVD_Image.iso of=/dev/dvd obs=32k seek=0'
/dev/dvd: restarting DVD+RW format...
/dev/dvd: "Current Write Speed" is 4.1x1352KBps.
   31490048/2530975744 ( 1.2%) @4.0x, remaining 7:56 RBU 100.0% UBU   2.4%
 2512584704/2530975744 (99.3%) @4.0x, remaining 0:03 RBU 100.0% UBU  99.8%
builtin_dd: 1235840*2KB out @ average 4.0x1352KBps
/dev/dvd: flushing cache
/dev/dvd: writing lead-out

As you can see, it took about 8 minutes (fast!) for this to finish. After it finished, I mounted the new DVD to test it (my image was udf, most linux CD/DVD images are iso9660):

[mirandam@atlas ~]$ sudo mount /dev/dvd /mnt/dvd -t udf

When I got back to the server, my DVD+RW was ready for me.

I plan to always leave a DVD+RW media in the drive so it can serve as an means for backup. Automating the process may also be a good idea.

More Info