5. Troubleshooting

This document describes how can you check and troubleshooting the VPL-Jail-System. For more details about VPL, visit the VPL home page or the VPL plugin page at Moodle.

5.1. Checking your server

5.1.1. Service status

You can check the status of the service using the following command in a terminal in your server

Using systemd

systemctl status vpl-jail-system

or using system V

service vpl-jail-system status
Status of the service

Example of systemctl output for an idle service

5.1.2. Accessible from a browser

You can check the availability of your execution server using the URL

http://servername:PORT/OK and https://servername:SECURE_PORT/OK

Where “servername” is the name of your execution server. The system must return a page with OK.

Note

The server must be accessible from the browser that uses VPL.

5.1.3. Accessible from Moodle

After adding your new server to the list of execution servers in your Moodle. You may go to “Advanced settings > Check execution servers” option of a VPL activity and you must see your server with the Current status to ready.

Jail servers check

Example of “Check execution servers” output

5.2. Troubleshooting

5.2.1. Reviewing logs

You can obtain a detailed log of the execution process by changing the log level at the configuration file. Commonly The logs will be written to “/var/log/syslog”.

You may filter and explore the vpl logs with the following command

grep vpl /var/log/syslog | less

5.2.2. Reporting a bug

If you think you found a bug, please, report it at the Github repository.

Please, describe your system configuration and how to reproduce the problem. Typical system configuration contains:

  • Operating system version
  • VPL-jail-system version
  • VPL-jail-system configuration file content
  • Network configuration (how your system reach the internet)
  • Screenshots
  • Other data you think is relevant

5.2.3. Asking for help

If you don’t found the problem, ask for help in the VPL Moodle forum.

Please, describe your system configuration and how to reproduce the problem. Typical system configuration contains:

  • Operating system version
  • VPL-jail-system version
  • VPL-jail-system configuration file content
  • Network configuration (how your system reach the internet)
  • Screenshots
  • Other data you think is relevant