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Cheatsheet

This page lists some technical details that Judgels admins should know in order to be able to debug issues arising from a Judgels deployment.

Core VM​

  • The following Docker containers must be running (check via docker ps):
    • judgels-client
    • judgels-server
    • rabbitmq
    • phpmyadmin (optional, can be stopped)
  • To tail running container logs: docker logs --tail=100 -f <container name>
    • e.g.: docker logs --tail=100 -f judgels-server

Judgels client​

  • Judgels client serves a static React app as the contestant web interface.
  • /opt/judgels/client/var/ is a mounted volume:
    • Config file is located at /opt/judgels/client/var/conf/judgels-client.js.
      • Values are populated from vars.yml during deployment.

Judgels server​

  • Judgels server serves the admin web interface and the API server endpoints.
  • /opt/judgels/server/var/ is a mounted volume:
    • Config file is located at /opt/judgels/server/var/conf/judgels-server.yml.
      • Values are populated from vars.yml during deployment.
    • Data files are located at /opt/judgels/server/var/data/.
    • Log files are located at /opt/judgels/server/var/log/.

Nginx​

  • The site config files are located at:
    • /etc/nginx/sites-available/judgels-client
    • /etc/nginx/sites-available/judgels-server-admin
    • /etc/nginx/sites-available/judgels-server-api
    • /etc/nginx/sites-available/letsencrypt

MySQL​

  • Database name: judgels
  • Database username: vars.yml -> db_username
  • Database password: vars.yml -> db_password
  • phpMyAdmin is available at http://<core VM IP>:8080
  • To check MySQL status: service mysql status

RabbitMQ​

  • The management web interface is available at http://<core VM IP>:15672.
  • To check the current grading queue, log in to the management web interface above using the credentials from vars.yml -> {rabbitmq_username, rabbitmq_password}, then click the Queues tab.

Grader VM​

  • judgels-grader Docker container must be running (check via docker ps).
  • To tail running grader logs: docker logs --tail=100 -f judgels-grader.

Judgels grader​

  • /opt/judgels/grader/var/ is a mounted volume:
    • Config file is located at /opt/judgels/grader/var/conf/judgels-grader.yml.
      • Values are populated from vars.yml during deployment.
    • Log files are located at /opt/judgels/grader/var/log/.
  • Judgels grader uses Isolate as the sandbox for grading submissions:
    • The Isolate binaries are located at /judgels/isolate/bin in the Docker container.
    • The Isolate boxes are located at /var/local/lib/isolate/<box id> in the Docker container.
    • For example, to check active boxes:
      docker exec -it judgels-grader ls /var/local/lib/isolate