Building a Call Center with LTSP and Soft Phones

# su to the user and generate their SSH keys
su - "$LOGIN" -c "ssh-keygen -q -t dsa -C '' -N '' -f "$HME"/.ssh/id_dsa"
#
# cp the new public key to the authorized_keys file
cp "$HME"/.ssh/id_dsa.pub "$HME"/.ssh/authorized_keys
chown "$LOGIN":"$( echo $GID | awk '{print $2}')" "$HME"/.ssh/authorized_keys
#
# update the NIS stuff
(cd /var/yp; make > /dev/null)

Aside from configuring local applications to run on the client terminals, we also need to make sure the sound cards are active when the thin clients boot. Normally, one would set SOUND = Y, SOUND_DAEMON = <nasd or esd>, VOLUME = <default volume level> and possibly SMODULE_01 = <ISA configuration string>. However, doing so not only causes the sound driver to be loaded into the kernel, but it starts the sound dæmon, which we do not want. We need the sound card to be available for KPhone when it starts on the terminal.

What we do instead is set SOUND = N to keep the normal sound system from being activated and MODULE_01 = <kernel module for the PCI soundcard>, because LTSP does not have isapnp support, so audio needs a PCI audio device. We also set RCFILE_10 = "kphone" to run the initial configuration script to ready the system for KPhone by using the audio device. Then, in /etc/rc.d in the clients' root filesystem, we put the KPhone script (Listing 3) to enable access to the /dev/sound/* files. -rwrwrw access is not the most secure, but because only one user is running processes on the terminal at a time, it works fine. Finally, we turn on the microphone and adjust the gain and volume levels.

Now that you have the LTSP environment configured and operational, you can build the LBE. Getting LBE from CVS is as simple as:

cvs -d :pserver:anonymous@cvs.ltsp.org:/usr/local/cvsroot checkout -s

You then need to su to root—using sudo with the LBE doesn't reliably work—and run ./build_all. You can take a break here, as the build of LTSP in LBE takes some time to complete.

Once you have the new root filesystem for the terminals built, change your DHCP configuration to refer to that boot image and root filesystem, and restart your DHCP server. You probably want to move /etc/lts.conf from your old LTSP root filesystem to the new one. You also should move the system-wide SSH known-host keys—the ones you created as per the Local Applications section of the LBE document—to the new filesystem.

Now we need to build the Qt libraries and then KPhone inside the clients' root filesystem. The LTSP Build Environment (LBE) makes this much more manageable. Adding packages for building in the environment amounts to creating a package.def file in a directory named for the package. The package.def files describe how to get, verify the download, unpack, configure, build and install the package software. The build script in the ltsp-src directory then does a chroot and executes the build process.

Through trial and error and discussions on the LTSP IRC channel (see Resources), we were able to construct the required package.def files (see Resources for those files). Constructing the package.def file for building Qt, in ltsp-src/qt under the LBE root, was a straightforward process. Each build exported the same variables to the build environment. Notice, also, that threading is turned on explicitly at the CONFIGURE stage. KPhone builds much more easily if Qt has threading enabled, but it is not enabled by default in Qt.

Building KPhone was a bit more complicated. The package.def file (see Resources) works well enough, but the x-includes configuration option does not seem to change the resulting Makefiles. This would cause compilation errors when building trayicon.cpp. Manually adding -I/usr/X11R6/include to CFLAGS in kphone/kphone/kphone/Makefile (Listing 4) after the configuration stage seemed to fix the problem, however. The steps to build KPhone in LBE are then:

ltsp-src# ./build --configure --only=kphone
ltsp-src# vi kphone/kphone/kphone/Makefile
   (Add "-I/usr/X11R6/include" to CFLAGS)
ltsp-src# ./build --only=kphone

We also noticed that the icons were not being located properly by KPhone at first. Making a link to ../../share/kphone in opt/ltsp/i386/usr/share from the LBE root—/usr/share from the clients' root—allowed KPhone to find the icons correctly.