Friday, June 28, 2013

Relying more on Desktop Client for Emails

After switching to Akregator from Google Reader and learning to live with a little inconvenience, I was struck by a comment about the danger of email accounts being broken into by the criminal elements.

I now have setup an imap account and am using Kmail. Contents of any folder/label which need not available for easy access online, I plan to move to a local folder. I will miss out on the power of Google search, but I think, along with consuming less energy, learning to live with some technological inconveniences is the preferred/imperative option.

Update - Came across an interesting news of excessive reliance of technology -  When technology fails a news anchor, there are no words.

Thursday, June 20, 2013

Life after Google Reader - Akregator

Web based services are convenient. It is far too easy to get used to them. I tend to look at my rss feeds from at least two systems. So, it seemed that I will use one of the online services which are trying to replace Google Reader and make the transition as painless as possible.

In view of the recent disclosures about Prism, opting for a little inconvenience is not a bad idea.

I am now quite comfortable with Akregator. One advantage is that I can see and access the entries I have already read as well. The responsiveness is very good.

To switch between machines, I take a tar backup of  .kde/share/apps/akregator from one machine and restore it on the other. Since it is a bit of a nuisance, I am organizing my net activities to normally use one system only for reading rss feeds and switch rarely.

It is not a very serious constraint and probable saves me distractions.

The mail services of our ISP are very unreliable otherwise I might have seriously considered at least partially moving from gmail.

As long as software read the content, I was unaffected; hence, no impact of Microsoft's criticisms of Google. This is probably more common  than just  for me as stories about Eliza illustrate -
Another story tells of the author's secretary using Eliza when he entered the room. The secretary asked her boss to leave until she had finished her conversation.
The author also considered putting in a module that recorded peoples conversations. This was greeted with accusations that Weizenbaum was spying on their secrets and innermost thoughts.
So, humans reading our content is another issue! 

Robots, however, guide and save humanity :)

Inactive logical volume after upgrading to Fedora 19

I upgraded my netbook to Fedora 19 beta version using yum. The process was smooth and went through without a hitch.

The problem came up on rebooting. Systemd waited and finally failed to mount home, which was a logical volume. This seemed strange as root and swap were also on the same volume group and were being used.

Finally, lvscan showed that the home logical volume was inactive. The command
lvchange --activate y 
worked and it was a relief to realize that the home logical partition was perfectly fine.

Unfortunately, rebooting the system showed the same problem. The cause of the problem was that all the lvm2 services were disabled.

Enabling lvm2-monitor.service resolved the issue :)

Friday, April 12, 2013

NFS root unexpectedly squashed

While experimenting with setting up ltsp on Fedora 18, I came across a strange NFS behaviour which took quite some time to iron out.

I was already exporting /opt as a read only file system; however, with root squashed. LTSP added another export for /opt/ltsp with no_root_squash option. 
/opt *(ro,sync,no_subtree_check)
# export for LTSP version 5
/opt/ltsp   *(ro,no_root_squash,async,no_subtree_check)

Everything seemed to be sort of working with a few strange effects, e.g. I could not use passwords and some ltsp scripts were failing.
The problem was that root seemed to be still squashed:
[anil@localhost ~]$ sudo mount amd:/opt/ltsp/x86_64 /mnt
[anil@localhost ~]$ cd /mnt/home
[anil@localhost home]$ ls -l
total 8
drwxrwx--- 2 anil  anil  4096 Apr  6 13:04 anil
drwx------ 2 guest guest 4096 Apr 10 12:35 guest
[anil@localhost home]$ sudo su
[root@localhost home]# cd anil
bash: cd: anil: Permission denied
A workaround was to use fsid=0 although whatever documentation I came across seemed to suggest that it was no longer needed:
/opt/ltsp   *(ro,fsid=0,no_root_squash,sync,no_subtree_check)
Unfortunately, I had forgotten that /opt was also being exported and noticed it only after finding the work-around and getting ltsp to work on Fedora 18.

Sunday, March 31, 2013

Arch Linux installation using ipxe and a Fedora server

Arch Linux is great way to learn, e.g. installing Arch Linux booting over the network. As is usual with Arch Linux, the documentation for the process is excellent. Surprisingly, a mirror in India gave an excellent speed and low latency so even the first stage went well.

Since I was experimenting with ipxe, I decided to install Arch Linux using the iso and ipxe. Using dnsmasq was no problem. However, since I use Fedora and the default is dhcpd, I wanted to make it work with dhcpd. The problem  was finding the equivalent options of dhcp-option-force.

The issue was that the client would try to search for cfg file as per its rules and ignore the specification in the dhcpd configuration file. The solution was available on the syslinux wiki in response to
Can I send information to PXELINUX via special options in the DHCP response?
It is much harder syntax than the dnsmasq's dhcp-option-force but worked.

Saturday, March 30, 2013

Install an OS from a DVD iso without booting

While experimenting with LTSP on Fedora18, I realized that I would have to have a supported environment in order to be able to understand the failure on Fedora. I had an iso file of Scientific Linux 6.3 and decided to use that.

Since ltsp-build-client installs an OS in a chroot environment while the system is operational, I decided to see if I could use a LTSP script to install the Scientific Linux on a free partition.

A python program, chroot-creator, seemed a likely prospect.
  1. Commented a few lines in chroot-creator meant specifically for LTSP clients. 
  2. Chose a suitable kickstart file 
  3. Loop mounted the iso image and used it as the yum repository
  4. Started installation on on the free partition which failed.
Installation was not possible as the partition needed to be mounted and the chroot-creator installs the OS in a directory which should not be existing. So, the installation was successfully done in a directory 'Install' under the mount point.

After the installation:
  1. In Install:
    # mv * ..
  2. Modify fstab file for Scientific Linux
  3. Run grub2-mkconfig. It should find and include the Scientific Linux partition.
  4. Chroot to the SL partition
  5. Change password for root. Create additional users if needed.
Scientific Linux should now be a usable boot option.

This process should work with any distribution which is compatible with yum on Fedora.

Note: the experimental version of LTSP scripts now uses mock and chroot-creator program is not included.

LTSP On Fedora 18 using client created on Ubuntu 12.10

Exploration of LTSP turned out to be a very interesting challenge. My motivation was to write a monthly column for Linux For You.

My primary system runs Fedora 18. I thought that I would be able to get the scripts to run on Fedora 18 in spite of the explicit caution that Fedora 15 onward is not supported. I haven't succeeded so far but I did succeed in getting an client image created on Ubuntu 12.10 to run on Fedora 18.

I installed the server scripts from the repository for experimental version of LTSP 5 for Fedora 18. This ensured that that the ldminfod version was compatible with the ldm version on Ubuntu 12.10 client.

Ubuntu uses nbd by default. Unionfs root was not working with NFS root on Ubuntu as well. So, nbd version 3.1.1 needed to be installed on Fedora. The version in Fedora repository is 2.9.20.

LTSP scripts run nbd server using xinetd while Ubuntu 12.10 runs nbd-server as a system service. Since the xinetd option did not work, nbd-server was started using a system service script. The key extract from nbd-server script is:

test -x $DAEMON || exit 0
case "$1" in
    daemon $DAEMON 10809 -C /etc/nbd-server/config
The port has to be 10809 to be compatible with the -N option used by ndb-client on Ubuntu client.

/opt/ltsp/amd64, /etc/nbd-server and  /var/lib/tftpboot/ltsp/amd64 directories was copied from Ubuntu to Fedora. The following were the final steps:

  1. Run ltsp-update-sshkeys
  2. Run ltsp-update-kernels
  3. Run ltsp-update-image amd64 -f
  4. Change the dhcpd configuration files to use the amd64 directory in tftpboot instead of i386. I modified the /etc/dhcp/dhcpd.conf file and did not use the ltsp-dhcpd script.
If all has gone well, you will get a LDM login screen with Ubuntu theme. The sessions available will be the ones on Fedora 18 and you should be able to login to a session using your Fedora 18 credentials!

Friday, February 22, 2013

Booting Porteus over the LAN from Fedora 18 server

Continuing my experiments with diskless options, I was going through RAM resident distributions on Wikipedia. Porteus appealed to me as it was able to run KDE desktop from RAM. The newly released version is packaged to boot off the network from a Porteus system with no additional effort.

I wanted to boot from my existing Fedora 18 system and I wanted to avoid using tftp. The recipe I used is as follows:

In order to make sure that both tftp and html could be used:
$ sudo ln -s /var/lib/tftpboot /var/www/html/tftpboot

Obviously, httpd and dhcpd are enabled. There is no need to enable tftp in /etc/xinetd.d/tftp. The following steps were needed in the tftpboot directory:
$ sudo mount -o loop Downloads/Porteus-v2.0-x86_64.iso /mnt
$ sudo mkdir /var/lib/tftpboot/porteus
$ sudo cp -r /mnt/boot/syslinux/* /var/lib/tftpboot/porteus
Now, we need to edit /etc/dhcp/dhcpd.conf. It's content (for my network) will be:
# dhcpd.conf
# configuration for pxe from
  option space pxelinux;
  option domain-name-servers,;
  option pxelinux.magic code 208 = string;
  option pxelinux.configfile code 209 = text;
  option pxelinux.pathprefix code 210  = text;
  option pxelinux.reboottime code 211 = unsigned integer 32;

  subnet netmask {
          option routers;

          class "pxeclients" {
                  match if substring (option vendor-class-identifier, 0, 9) = "PXEClient";
                  option pxelinux.pathprefix "";
                  filename "";
 Finally, we need to copy the base os files into the http root, i.e.
$ sudo cp /mnt/porteus/base/* /var/www/html

We need to disable the welcome screen for Porteus to successfully boot from the apache server. So, comment all lines in

Now, restart the httpd and dhcpd servers.

On the client machine, I am using grub2. The client is configured as follows:
  1. Download ipxe.iso
  2. Extract ipxe.krn from the iso and copy it in /boot of the client.
  3. Edit /etc/grub.d/40_custom and add the following lines:
    menuentry "ipxe"{
          linux16 /boot/ipxe.krn
  4. Create a new grub.cfg
    Fedora:  /boot/grub2/grub.cfg using grub2-mkconfig
    Ubuntu: /boot/grub/grub.cfg using grub-mkconfig
Reboot the client. Choosing the ipxe option should bring up the Porteus boot menu and it should boot into kde or lxde depending upon the option selected.

Thursday, February 21, 2013

Booting over network - Use ipxe and forget etherboot/gpxe

I was playing around with diskless options and decided to see if I could boot Puppy Linux over the network. As usual, it was easy to find a recipe on the net. I got the gpxe boot linux kernel image for forcedeth driver.

The surprise was the terrible performance I got on a 100mbps network. I did not wait for it to finish booting! On a 1GB network, the performance was 'merely' bad. I did not expect tftp to be so bad!

Searching the net, I realized that gpxe allows html as the protocol instead. There was no change if I used pxelinux.0 and it was even worse if I used gpxelinux.0! I tried pxelinux.0 and gpxelinux.0 from version 5.01 of Syslinux with no improvement. However, the performance was better on my lenovo netbook which needed the r8169 driver. The performance using html protocol was still not any better.

The search for an answer led to the ipxe project. Mercifully, the ipxe.krn from the iso file worked for both the cards. Now, the performance over html was significantly better. It took half the time to boot Puppy Linux using html protocol.

Friday, January 18, 2013

Upgrading to Fedora 18 using Yum - Nouveau causes system freeze?

The documentation for upgrading fedora using yum seems to be much better than before. A very nice script which automates the instructions was terrific. The upgrades of my desktop and the netbook were very smooth. After the upgrade, I installed the Cinnamon desktop as well. It is very nice though I will stick to KDE as I am now comfortable with it.

There was, however, a surprise on the desktop. On booting into Fedora 18, the display vanished and the system hung. The system came up in muti-user mode but not in graphical interface. Gdm was the problem. I switched to kdm. The login screen came and was fine in KDE. However, the system again froze when I tried Cinnamon or Gnome desktops. LXDE worked but the system froze as soon as I started Firefox!

KDE desktop was working with desktop effects disabled. If I enabled them, the desktop froze.

The desktop worked fine with the nomodeset option for booting the kernel. However, it was using the vesa driver. So, the problem is with nouveau driver on "GeForce 6150SE nForce 430" hardware.

Another curious result. The system is working fine with the kernel 3.6.11-1.fc17.x86_64 from fedora 17, which has made it possible to continue with Fedora 18 on the desktop.

Need to reconfirm the problems I faced on the desktop as I did not find a bug report with similar issues.

On Lenovo S10-3, I have so far not faced any issues related to the upgrade.