The only package specific configuration is given through the command line options. You may however want to run a more ‘robust’ setup then simply starting the application in a screen session. In order to do so, we will use systemd for starting our application and use apache2 as a reverse proxy. We recommend not running this system on a broad subnet, because it is broadcasting over UDP, use a private subnet for the nodes if possible.

python3.7 on Ubuntu 18

Install python 3.7 on Ubuntu from source (or from your package manager if it’s included), you need the development headers (Python.h):

update-alternatives --install /usr/bin/python python /usr/bin/python2.7 1
update-alternatives --install /usr/bin/python python /usr/bin/python3.6 2
update-alternatives --install /usr/bin/python python /usr/bin/python3.7 3

Now run update-alternatives –config python and select 3.7 as the default interpreter. You need to install pip, so run:

curl -o

You should now be able to install dcron from pip.


Download our systemd example service file dcron.service from the repository and adapt where necessary. Note that the most important thing is the user the service runs as, the user will need full application access for the cronlike jobs.

The usual spot for the file is /etc/systemd/system/dcron.service. After downloading and editing run systemctl daemon-reload for the service to show up. Now run systemctl start dcron to check if everything is working. The webservice should be available under port 8080 (or whatever you configured).


Our system doesn’t do any authentication, so we will configure apache2 as a reverse proxy with authentication.

Install apache2: apt install apache2

Configure apach2 modules:

a2enmod proxy
a2enmod ssl
a2enmod proxy_http
a2ensite default-ssl.conf
systemctl restart apache2

Edit /etc/apache2/sites-available/default-ssl.conf:

<IfModule mod_ssl.c>
   <VirtualHost _default_:443>

           ErrorLog ${APACHE_LOG_DIR}/error.log
           CustomLog ${APACHE_LOG_DIR}/access.log combined

           SSLEngine on
           SSLCertificateFile /etc/ssl/certs/ssl-cert-snakeoil.pem
           SSLCertificateKeyFile /etc/ssl/private/ssl-cert-snakeoil.key

           <FilesMatch "\.(cgi|shtml|phtml|php)$">
                           SSLOptions +StdEnvVars
           <Directory /usr/lib/cgi-bin>
                           SSLOptions +StdEnvVars
           BrowserMatch "MSIE [2-6]" \
                           nokeepalive ssl-unclean-shutdown \
                           downgrade-1.0 force-response-1.0
           BrowserMatch "MSIE [17-9]" ssl-unclean-shutdown

           ProxyRequests On
           ProxyPreserveHost On

           <Proxy />
               Order deny,allow
               Allow from all

           <Location />
             Order deny,allow
             Allow from all

             ProxyPass http://localhost:8080/
             ProxyPassReverse http://localhost:8080/

             AuthType Basic
             AuthName "dcron"
             AuthBasicProvider file
             AuthUserFile /etc/apache2/.htpasswd

             Require valid-user

Edit /etc/apache2/sites-available/000-default.conf:

<VirtualHost *:80>

   ServerAdmin webmaster@localhost

   ErrorLog ${APACHE_LOG_DIR}/error.log
   CustomLog ${APACHE_LOG_DIR}/access.log combined

   Redirect / https://external.machine.address

For every user you want to give access, run the following command:

htpasswd -c /etc/apache2/.htpasswd <user>

and enter a password.

Log file rotation

Check if logrotate is installed on your system, if not install it apt-get install logrotate. Create the file /etc/logrotate.d/dcron:

/var/log/dcron.log {
    size 100M
    rotate 12
    create 644 root root

You should now be good to go.