VirtualExam

Virtual Exam

Please read documentation: virtual exam

In summary, logging into <class_account>vx e.g. cs1234vx starts the exam. The exam files are located in <class_account>exam e.g. cs1234exam, follow (symbolic link) currentexam. You have ssh access to both these accounts if you have ssh access to the corresponding class account.

Useful scripts

~give/stable/bin/prac-install-vx [from_prac] to_prac
- set up a standard virtual exam environment in <class_account>exam
- if from_prac != to_prac
  - copy from_prac from virtual directory if exists
  - copy from_prac from gaol directory otherwise
- else
  - copy from_prac from gaol directory
  gaol is the old exam environment.
priv passwd
- change the <class_account>vx password before and after the exam with this script

priv chown wildcard

change ownership of work directories from 90<uid> to exam account at the end of the exam to access the students' files

note that after changing ownership, students can't start the exam

marimba % ls -la exams/19T1midterm/work
total 16
drwxrwxrwt  4 en1811exam en1811exam 4096 Mar 14 21:19 .
drwxr-x---  6 en1811exam en1811exam 4096 Mar 12 17:50 ..
drwxrws--- 14     929389 en1811exam 4096 Mar 14 21:36 z5016573
drwxrws--- 13     906444 en1811exam 4096 Mar 12 20:02 z8470184

/home/vxconf/vx.conf.d is the repository for vx.conf files for commonly used products e.g. gcc, python, gedit, fluxbox

prac-install-vx creates ~/exams/<prac>/etc/vx.conf.d and fill it with symbolic links to vx.conf files in /home/vxconf/vx.conf.d

remove any sym links not needed. exam takes less time to start up if there are less software.

-rw-r--r-- 1 vxconf vxconf  433 Mar 14 21:31 000-header.conf
-rw-r--r-- 1 vxconf vxconf  220 Mar 14 21:31 100-basicx.conf
-rw-r--r-- 1 vxconf vxconf  159 Mar 14 21:31 100-fontconfig.conf
-rw-r--r-- 1 vxconf vxconf   99 Mar 14 21:31 100-rxvt.conf
-rw-r--r-- 1 vxconf vxconf  202 Mar 14 21:31 200-wm-fluxbox.conf
-rw-r--r-- 1 vxconf vxconf  351 Mar 14 21:31 200-wm-fvwm.conf
-rw-r--r-- 1 vxconf vxconf  608 Mar 14 21:31 300-interp-perl.conf
-rw-r--r-- 1 vxconf vxconf  210 Mar 14 21:31 300-interp-pylint.conf
-rw-r--r-- 1 vxconf vxconf 1894 Mar 14 21:31 300-interp-python.conf
-rw-r--r-- 1 vxconf vxconf  860 Mar 14 21:31 300-toolchain-binutils.conf
-rw-r--r-- 1 vxconf vxconf 3374 Mar 14 21:31 300-toolchain-clang.conf
-rw-r--r-- 1 vxconf vxconf 1690 Mar 14 21:31 300-toolchain-gcc.conf
-rw-r--r-- 1 vxconf vxconf  105 Mar 14 21:31 300-toolchain-gdb.conf
-rw-r--r-- 1 vxconf vxconf   79 Mar 14 21:31 300-toolchain-make.conf
-rw-r--r-- 1 vxconf vxconf  212 Mar 14 21:31 300-toolchain-valgrind.conf
-rw-r--r-- 1 vxconf vxconf   84 Mar 14 21:31 400-browser-firefox.conf
-rw-r--r-- 1 vxconf vxconf   54 Mar 14 21:31 400-browser-midori.conf
-rw-r--r-- 1 vxconf vxconf  369 Mar 14 21:31 400-browser-nautilus.conf
-rw-r--r-- 1 vxconf vxconf   84 Mar 14 21:31 400-viewer-evince.conf
-rw-r--r-- 1 vxconf vxconf  110 Mar 14 21:31 400-viewer-xpdf.conf
-rw-r--r-- 1 vxconf vxconf  328 Mar 14 21:31 500-editor-emacs.conf
-rw-r--r-- 1 vxconf vxconf  300 Mar 14 21:31 500-editor-gedit.conf
-rw-r--r-- 1 vxconf vxconf   52 Mar 14 21:31 500-editor-idle.conf
-rw-r--r-- 1 vxconf vxconf   47 Mar 14 21:31 500-editor-nedit.conf
-rw-r--r-- 1 vxconf vxconf   96 Mar 14 21:31 500-editor-spyder3.conf
-rw-r--r-- 1 vxconf vxconf   26 Mar 14 21:31 500-editor-vi.conf
-rw-r--r-- 1 vxconf vxconf  161 Mar 14 21:31 500-editor-vim.conf

thanks to Jashank for the original idea

Problems - Tips on how to solve

ensure that multiple logins are possible without files in the work directory being clobbered. use "cp -n" or "tar --keep-newer-files" or "unzip -n"

when the exam crashes after you authenticated with your zid, check stderr.log file under <exam_account>/var directory. Look at the latest directories.

marimba % ls -lt ~/var | head -5
total 988
drwxr-xr-x 2 cs9024exam cs9024exam 4096 Feb 13 06:59 marimba-25528
drwxr-xr-x 2 cs9024exam cs9024exam 4096 Feb 12 20:49 wagner-7800
drwxr-xr-x 2 cs9024exam cs9024exam 4096 Feb 12 20:33 vx4-45795
drwxr-xr-x 2 cs9024exam cs9024exam 4096 Feb 12 18:39 vx4-34624

after changing ownership of the work directories (to exam account), you can't start the exam with the same work directories.
- create a new toplevel work directory.
```
cd ~/exams/18s2supp
mv work work.19dec
mkdir work
chmod 1777 work
```
- or remove the student's work directory
```
cd ~/exams/18s2supp/work
priv chown z5555555
rm -r z5555555
```
path mounted on top of a previous mount cause the exam environment to abort on subsequent logins. The exam environment attempts to delete an existing student's gaol by unmounting directories.
```
vx08 % cat var/vx04-2104607/stderr.log
umount: /var/gaol/meicheng/usr/lib/python3/dist-packages: not mounted.
```

Manually umount "/var/gaol/meicheng/usr/lib" to allow the gaol to be removed and therefore allow student to login without exam crashing. To remove the gaol /home/virtualexam/bin/delete_gaol meicheng