Tips and Tricks/Maintenance

Some maintenance and management tasks are shown below.

Update Server IP
When the server IP adress has changed, you should update the client ssh keys with ltsp-update-sshkeys.

When using NBD, you should also update your images with ltsp-update-image.

Update a Client Image
You can perform any kind of maintenance on a client install, for instance upgrade some are all of the installed packages or add new ones for ltsp-localapps. Basically, you chroot into the environment, do the maintenance and exit.

When using NBD, you should also update your images with ltsp-update-image.

Upgrade Client Kernel
Install the new kernel

$ sudo ltsp-chroot -m $ sudo apt-get install linux-image-??? linux-headers-???

Edit the /opt/ltsp/i386/etc/ltsp/update-kernels.conf file

# Default boot options # Use a menu for booting #PXELINUX_DEFAULT=menu # Set default timeout to 10 seconds (hundreths of a second) TIMEOUT=100 # Set default boot item on timeout ONTIMEOUT=ltsp-NFS-4.9.0 # Use ifcpu64.c32 to detect 64-bit, PAE or 32-bit machines. #PXELINUX_DEFAULT=ltsp-ifcpu64-NFS PXELINUX_DEFAULT=ltsp-NFS-4.9.0 #IFCPU64=true

Update kernel (first exit chroot section)

sudo ltsp-chroot /usr/share/ltsp/update-kernels sudo ltsp-update-kernels

This should affect the /var/lib/tftpboot/ltsp/i386/pxelinux.cfg/default file.

Now to test, boot a thin client, login and check

ltsp-localapps xterm uname -a

Moving an NFS Chroot
You might want to move the client chroot installation on the server. This can be easily done with the following command. Don't forget to change to NFS entry in /etc/exports and reload it on the server prior to booting the client again.

Backup/Restore Chroot
If you want to copy the client installation to another computer or make a backup, you can archive it with tar. Remember that after copying a client installation, you will also want to ltsp-update-kernels, ltsp-update-sshkeys and ltsp-update-image if you are running NBD.

To create a tar gzip archive of a chroot, run the following command:

To restore a chroot from a tar gzip image, run the following command:

Quick lookup
If you're interested to view the machines currently logged onto the server you have several options. The first is the arp command. This shows the machines that are connected to your server:

While arp shows all connected machines, the following command only shows the ips of connected LTSP clients:

Bash script
But if you want a solution that makes it easy to check who is online and from which machine, you should write your own bash script.

First we save this as /usr/local/bin/whoison.awk BEGIN { format = "%s %-10s %-6s  %-5s   %-13s  %-20s\n" }      # on every line... /LTSP_CLIENT/ { user      = $1 PID       = $2 login_time = $9 ip_address = $13 hostname  = $14 sub(/LTSP_CLIENT=/,"",ip_address) sub(/LTSP_CLIENT_HOSTNAME=/,"",hostname) printf(format, "   :", user, PID, login_time, ip_address, hostname) }

Then we save this as /usr/local/bin/whoison (remember to chmod both files to 755) echo "Users:" echo "=================================================================" ps aux | awk -f /usr/local/bin/whoison.awk

With this done you have your very own look up command