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Launching environment

DoDWAN

The DoDWAN platform

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Launching environment

 The JVM that hosts DoDWAN needs to know minimal information to function properly, namely the name of the DoDWAN host and the name of some working directories. The pieces of information needed take the form of Java properties that are typically passed to the JVM as arguments. Note that a default value exists for each of them, so explicit definitions for the properties are actually optional.

DoDWAN host

The name of the DoDWAN host is usually the actual name of the host running DoDWAN but you may use any another name (for simulation purposes for example), provided that it is unique among the participants in the network.

For setting the DoDWAN host, Java property dodwan.host is looked for at startup, when launching the JVM. If no such property is found, the hostname (as found in the $HOSTNAME shell variable in Linux systems) is taken as a default value.

DoDWAN working directories

DoDWAN uses three working directories:

  • The DoDWAN home directory: this is the directory where are placed the JAR file containing the code of DoDWAN (in subdirectory lib) and the default connfiguration file (in subdirectory conf).
  • The DoDWAN var directory: this is the directory in which DoDWAN stores its cache and other internal information.
  • The DoDWAN base directory: this is the directory in which the user data is stored (eg the user preferences for DoDWAN configuration).

Note that the DoDWAN var and the DoDWAN base directories may not exist when DoDWAN starts. In this case, they will be automatically created.

Files are not stored directly under the DoDWAN var and the DoDWAN base directories. They are actually placed in a subdirectory that has the name of the DoDWAN host, so that multiple instances of DoDWAN can run concurrently on the same machine for simulation purposes.

DoDWAN in a user-only environment

In the simplest deployment configuration, all DoDWAN files are placed in a unique tree in a user directory, typically where the DoDWAN package was unzipped. The root of this tree is passed to the JVM in the dodwan.root property.

If no dodwan.root property is found (and the properties presented in the next section are not all defined), the default value $HOME/DoDWAN is taken.

Here is an example of a set of arguments passed to the JVM when launching DoDWAN on Linux:

java -Ddodwan.host=zeus \
 -Ddodwan.root=$HOME/my_dodwan \
 ...

In this case, the DoDWAN home, DoDWAN var and DoDWAN base directories are expected to be respectively $HOME/my_dodwan/home, $HOME/my_dodwan/var, and $HOME/my_dodwan/base, with a subdirectory zeus in the last two ones.

DoDWAN in a user and admin environment

Alternatively, DoDWAN may be deployed in a environment mixing user directory and non-user directory (i.e. directories with distinct access rights). In this case, instead of only one root directory, the JVM must be passed three distinct directories:

The DoDWAN home directory (property dodwan.home). It may be only readable by the JVM that runs DoDWAN. The DoDWAN var directory (property dodwan.var). It should be writeable by the JVM that runs DoDWAN. The DoDWAN base directory (property dodwan.base). It should be writeable by the JVM that runs DoDWAN.

Here is an example of a set of arguments passed to the JVM when launching DoDWAN, provided that the DoDWAN package has been installed in /usr/local:

java -Ddodwan.host=zeus \
 -Ddodwan.home=/usr/local/DoDWAN/home \
 -Ddodwan.var=/var/DoDWAN \
 -Ddodwan.base=$HOME/.dodwan \
 ...