Simple Computer Classroom Management System
The article was written for informatics teachers who are tired of being engaged in the constant restoration of order in the classroom and on student computers. For those who value time and health.
We will need:
1. Install on all computers class OS Linux. Distribution choose to your taste.
2. Install packages on all student computers: openbox, tint2, pcmanfm, gxkb, x11vnc (server and client), vlc
3. In addition, the RuleUser program must be installed on the teacher’s computer, more details will be given below.
4. Create guest student computers on guest.
5. Install and configure the sshd package on all computers.
6. Copy the attached configuration files to student and teacher computers.
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Note. In this example, the teacher’s computer has an ip address: 192.168.1.100/24. Student computers have addresses starting at 192.168.1.101/24.
1. We exclude the possibility of changing the desktop settings of student computers.
To do this, use the openbox bundle (for managing windows) + tint2 (taskbar) + pcmanfm (for displaying desktop icons) + gxkb (for displaying the status of the input language).
Desktop icons student computers will be located on the teacher's machine. In this way, the teacher will control what is available to the students. On student machines, you need to add a line to the / etc / fstab file to mount the nfs folder from the teacher’s car:
2. We make it possible to switch the input language by means of the X server, for this we create the file /etc/X11/xorg.conf.d/10-keymap.conf on the student computers with the following contents:
Switch by Ctrl + Shift.
3. Download configs for: openbox , tint2 , pcmanfm , gxkb . We copy them where it should. This is usually ~ / .config
I draw your attention that in the openbox configurations there is an autostart script through which the x11vnc server is launched. As well as there is a refresh script for the desktop refresh, which is launched by pressing the F7 key. Just in case there is a call for the terminal by Ctrl + Shift + T. Students can not talk about these opportunities, this is done primarily for the convenience of the teacher.
4. Using the tools of a specific Linux distribution, or manually, install the openbox window manager by default. To do this, it is enough to change the value of the Session parameter in the ~ / .dmrc file like this:
5. Check that the sshd service is installed and started when the OS boots.
6. To enable students to connect their flash drives, I use the udevmon script, which automatically mounts them in the / media directory. This script must be loaded at system startup as a daemon. I have done this through /etc/rc.d/rc.local.
1. In most Linux distributions, nfsd is installed by default, so immediately proceed to configure it:
- create the folder / mnt / nfs and give it full access rights for everyone (command chmod 777 / mnt / nfs)
- add a line to the / etc / exports file:
- See that the following lines appear in the /etc/hosts.allow file:
- check that the rpc and nfsd services start when the OS boots.
2. Install the program RuleUser . This program is an authoring development of the Alt Linux company, and you will not find it in other distributors. But as a matter of fact, it is a python skip using the pygtk libraries, gtkvnc. Install these libraries if they are missing from your system.
3. Configure remote connections in the RuleUser program. This can be done using the graphical configurator, but you can also simply edit the file ~ / .ruleuser / config.cfg.
Here is the part of the configuration file for student machines:
The line “g1 = standalone, 10.” Here, g1 is a group of computers 1, the number of computers in a group is 10. Next is a description of the individual computers of the group. To simplify the configuration, you can copy the computer description lines by changing the computer numbers, ip addresses and unique identifiers (for the first computer in this config, this is 1418361570). In the graphical configurator, it will be a little longer.
4. Configure ssh to access student computers without entering a password:
- enter the command ssh-keygen -t rsa
it will create two keys in the user's home directory, one of them needs to be copied to remote machines to which you need access.
- copy the keys to all student computers:
After that, it will be possible to enter and manage the computer through the root and guest users. You will not need to enter a password.
The teacher has full access to student ssh computers. Through the RuleUser program, you can monitor students' activities, intercept control of their computers, block input, etc. The teacher gives students access only to those programs that are necessary for a particular lesson. To do this, drag the Gnome, XFCE or KDE menu with the icon of an application to the / mnt / nfs folder and update the students' desktop (with F7, or run the ssh update script).
I looked like this:
Pupil:
Teacher:
We will need:
1. Install on all computers class OS Linux. Distribution choose to your taste.
2. Install packages on all student computers: openbox, tint2, pcmanfm, gxkb, x11vnc (server and client), vlc
3. In addition, the RuleUser program must be installed on the teacher’s computer, more details will be given below.
4. Create guest student computers on guest.
5. Install and configure the sshd package on all computers.
6. Copy the attached configuration files to student and teacher computers.
')
Note. In this example, the teacher’s computer has an ip address: 192.168.1.100/24. Student computers have addresses starting at 192.168.1.101/24.
Student computers
1. We exclude the possibility of changing the desktop settings of student computers.
To do this, use the openbox bundle (for managing windows) + tint2 (taskbar) + pcmanfm (for displaying desktop icons) + gxkb (for displaying the status of the input language).
Desktop icons student computers will be located on the teacher's machine. In this way, the teacher will control what is available to the students. On student machines, you need to add a line to the / etc / fstab file to mount the nfs folder from the teacher’s car:
192.168.1.100:/mnt/nfs /home/guest/Desktop nfs ro,nolock,nocto,actimeo=3600 0 0 2. We make it possible to switch the input language by means of the X server, for this we create the file /etc/X11/xorg.conf.d/10-keymap.conf on the student computers with the following contents:
Section "InputClass" Identifier "Keyboard settings" MatchIsKeyboard "yes" Driver "evdev" Option "XkbLayout" "us,ru" Option "XkbVariant" "" Option "XkbOptions" "grp:ctrl_shift_toggle" EndSection] Switch by Ctrl + Shift.
3. Download configs for: openbox , tint2 , pcmanfm , gxkb . We copy them where it should. This is usually ~ / .config
I draw your attention that in the openbox configurations there is an autostart script through which the x11vnc server is launched. As well as there is a refresh script for the desktop refresh, which is launched by pressing the F7 key. Just in case there is a call for the terminal by Ctrl + Shift + T. Students can not talk about these opportunities, this is done primarily for the convenience of the teacher.
4. Using the tools of a specific Linux distribution, or manually, install the openbox window manager by default. To do this, it is enough to change the value of the Session parameter in the ~ / .dmrc file like this:
Session=openbox 5. Check that the sshd service is installed and started when the OS boots.
6. To enable students to connect their flash drives, I use the udevmon script, which automatically mounts them in the / media directory. This script must be loaded at system startup as a daemon. I have done this through /etc/rc.d/rc.local.
Teacher's computer
1. In most Linux distributions, nfsd is installed by default, so immediately proceed to configure it:
- create the folder / mnt / nfs and give it full access rights for everyone (command chmod 777 / mnt / nfs)
- add a line to the / etc / exports file:
/mnt/nfs 192.168.1.0/24(ro,sync) - See that the following lines appear in the /etc/hosts.allow file:
nfsd: 192.168.1.0/255.255.255.0 rpcbind: 192.168.1.0/255.255.255.0 mountd: 192.168.1.0/255.255.255.0 - check that the rpc and nfsd services start when the OS boots.
2. Install the program RuleUser . This program is an authoring development of the Alt Linux company, and you will not find it in other distributors. But as a matter of fact, it is a python skip using the pygtk libraries, gtkvnc. Install these libraries if they are missing from your system.
3. Configure remote connections in the RuleUser program. This can be done using the graphical configurator, but you can also simply edit the file ~ / .ruleuser / config.cfg.
Here is the part of the configuration file for student machines:
[group] group_list = 1 g1 = standalone,10 g1_1 = 1,guest,pc2,192.168.1.101,192.168.1.101,standalone,1418361570,,xfce,standalone,22,22,guest,guest,static,,/home/guest/.vnc/passwd,vncviewer -geometry 1366x768,vncviewer -fullscreen -MenuKey none,False,True,False,100,x11vnc -noxdamage -scale 1024x768,5900,$HOME/.ssh/authorized_keys,$HOME/.ssh/authorized_keys,,:0,,,,$HOME/.ssh/authorized_keys,/tmp,False,default,False,True,False,False,False,False,,x11vnc -noxdamage -scale 640x480,vncviewer -MenuKey none,False,x11vnc -noxdamage -defer 3000,False,False,True,,,,,,,,,,,,,,,,default,True,,,,,,,,,,,,,,False,10,mpgv,800x600,640x480,False,300,False,False,,False,vlc --network-caching=100 --qt-minimal-view --no-qt-error-dialogs --no-qt-privacy-ask,,,,,,,, g1_2 = 2,guest,pc3,192.168.1.102,192.168.1.102,standalone,1418361573,,xfce,standalone,22,22,guest,guest,static,,/home/guest/.vnc/passwd,vncviewer -geometry 1366x768,vncviewer -fullscreen -MenuKey none,False,True,False,100,x11vnc -noxdamage -scale 1024x768,5900,$HOME/.ssh/authorized_keys,$HOME/.ssh/authorized_keys,,:0,,,,$HOME/.ssh/authorized_keys,/tmp,False,default,False,True,False,False,False,False,,x11vnc -noxdamage -scale 640x480,vncviewer -MenuKey none,False,x11vnc -noxdamage -defer 3000,False,False,True,,,,,,,,,,,,,,,,default,True,,,,,,,,,,,,,,False,10,mpgv,800x600,640x480,False,300,False,False,,False,vlc --network-caching=100 --qt-minimal-view --no-qt-error-dialogs --no-qt-privacy-ask,,,,,,,, The line “g1 = standalone, 10.” Here, g1 is a group of computers 1, the number of computers in a group is 10. Next is a description of the individual computers of the group. To simplify the configuration, you can copy the computer description lines by changing the computer numbers, ip addresses and unique identifiers (for the first computer in this config, this is 1418361570). In the graphical configurator, it will be a little longer.
4. Configure ssh to access student computers without entering a password:
- enter the command ssh-keygen -t rsa
it will create two keys in the user's home directory, one of them needs to be copied to remote machines to which you need access.
- copy the keys to all student computers:
for i in 101..110; do ssh-copy-id -i ~/.ssh/id_rsa.pub guest@192.168.1.$i ; done for i in 101..110; do ssh-copy-id -i ~/.ssh/id_rsa.pub root@192.168.1.$i ; done After that, it will be possible to enter and manage the computer through the root and guest users. You will not need to enter a password.
Total
The teacher has full access to student ssh computers. Through the RuleUser program, you can monitor students' activities, intercept control of their computers, block input, etc. The teacher gives students access only to those programs that are necessary for a particular lesson. To do this, drag the Gnome, XFCE or KDE menu with the icon of an application to the / mnt / nfs folder and update the students' desktop (with F7, or run the ssh update script).
I looked like this:
Pupil:
Teacher:
Source: https://habr.com/ru/post/272475/
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