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StarExec is a cross community logic solving service


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StarExec is a cross community logic solving service developed at the University of Iowa under the direction of principal investigators Aaron Stump (Iowa), Geoff Sutcliffe (University of Miami), and Cesare Tinelli (Iowa).

Its main goal is to facilitate the experimental evaluation of logic solvers, broadly understood as automated tools based on formal reasoning. The service is designed to provide a single piece of storage and computing infrastructure to logic solving communities and their members. It aims at reducing duplication of effort and resources as well as enabling individual researchers or groups with no access to comparable infrastructure.

StarExec allows

  • community organizers to store, manage and make available benchmark libraries;
  • competition organizers to run logic solver competitions; and
  • community members to perform comparative evaluations of logic solvers on public or private benchmark problems.

Development details can be found on our public development wiki.



StarExec requires Ant to build, and has been tested with version 1.9.2. An installation guide for Ant is below, or you may use any applicable package manager.


StarExec requires Sass at build time to compile .scss stylesheets to .css. Sass depends on Ruby.

We are currently using Ruby Sass 3.4.24

Apache Tomcat

StarExec depends on Apache Tomcat 7.0.64. While newer versions may work, we have frequently seen that even minor version releases of Tomcat can have breaking changes for StarExec, so using a different version of Tomcat is not recommended.

A full release of Tomcat is included in the starexec package under the distribution/ directory. This is identical to a release that you can download from Apache, with the exception that the mysql-connector-java-5.1.22-bin.jar and file is included in the lib/ directory. This .jar file is required for StarExec to connect to its database, and as such we recommend that you install Tomcat using the provided archive. If you would like to install a clean copy of Tomcat, you will need to copy MySQL connector to the new lib directory.

PLEASE NOTE: We recently migrated our servers from centOS to Rocky8. Due to this, DRMAA is no longer a required dependency. Instead, we will be using qsub. For more information about this command, please see

If you install Tomcat using the provided archive, you may need to update permissions on the install directory to make Tomcat's scripts executable. This can be done, for example, by using chmod 700 -R tomcat_directory

MySQL and MariaDB

StarExec depends on MariaDB 5.5.56.


StarExec's backend refers to the utility that is responsible for accepting new jobs from the web app and distributing them over the available compute nodes. StarExec supports 3 different backend implementations: SGE, OAR, or a simple local backend implemented in StarExec itself.

To install SGE or OAR, you will need to refer to their documentation. In the case of OAR, the document distribution/OAR installation notes.txt describes extra installation steps you should take to configure OAR for use with StarExec.

The local backend is a primitive solution if you only want to run jobs on the same machine that StarExec is running off of. The local backend does not support multiple queues or nodes, and only a single job will run at a time.


StarExec is configured by Ant at build time.

StarExec's default configuration is specified by build/, but several properties will need to be overridden for a particular StarExec instance. These properties may be overridden in three ways:

  1. If build/ exists, any properties specified in this file will override the defaults
  2. Ant can be passed a .properties file if invoked with the -propertyfile option. Any properties specified in this file will override the defaults and any properties that exist in build/
  3. Individual properties can be set by invoking Ant with the -D<property>=<value> option. Any properties set this way will take precidence.

An empty configuration file is provided as This file also explains the properties that must be set for a particular StarExec instance.


DB.User must be set to the username of a MariaDB user that has full permissions for the database. DB.Pass must be set to the password for that user. This user will require all permissions in the StarExec database, excluding server administration permissions. If desired, a user with fewer permissions may be used by the compute nodes to report results to the database. This user only needs EXECUTE permission, and is configured via Cluster.DB.User and Cluster.DB.Pass. If unspecified, these will default to the values of DB.User and DB.Pass.


StarExec sends automated emails for several purposes, such as sending notifications when new users are registered or sending weekly status updates. To do this, StarExec requires an email account that it can send emails from. Email.User should be set to the username of the account to send from, and Email.Pass, Email.Smtp and Email.Port should be set as decribed.

StarExec is also configured to use a Email.Contact, which is intended to receive emails directed at StarExec admins. This email address will appear on the site for users who want to send bug reports or ask questions.


You will need to make sure that you have mapped the StarExec data directory, (data_dir), to a matching path on each compute node, as your compute nodes will need access to the StarExec data directory that exists on the head node.

Cluster.UserOne and Cluster.UserTwo (by default, sandbox and sandbox2 respectively) refer to users that will execute jobs on compute nodes. Ensure that these accounts exist on the head node and all compute nodes, and have appropriate permissions.

Create the star-web group.

Create the user tomcat and add this user to the star-web group, and change the primary group for tomcat to star-web. This is the user that you will need to use when starting up Tomcat using in the Tomcat bin/ folder. You should also ensure that tomcat is the owner of the entire Tomcat installation directory.

Finally, any users that are going to be administering StarExec should also be added to the star-web group. Being a member of star-web will be necessary for correctly executing the StarExec deploy scripts.

Create the sandbox group, and add Cluster.UserOne to this group. Create another group sandbox2 and add Cluster.UserTwo to this group. Add the tomcat user to both of these groups.

If you are using SGE as a backend, you need to create the user sgeadmin and ensure this user does have administrator privileges in SGE.

A sandbox directory will need to be created on the StarExec head node. This directory is used to execute user-provided scripts in a sandboxed environment, preventing them from affecting other parts of the system. You should create a directory at the location specified by sandbox_dir. Make the owner Cluster.UserOne, and make the group sandbox. Use chmod on the directory to make permissions 770. Additionally, use chmod g+s to set the GID for the directory. Finally, use the following command to ensure that new directories in the sandbox have g+rwx permissions.

setfacl -d -m g::rwx sandbox

The directory configured as Backend.WorkingDir needs to be created. tomcat should be the owner and star-web should be the group. Under this directory, create two directories named sandbox/ and sandbox2/. These should also use the tomcat user and the star-web group.

Sudo permissions need to be configured. StarExec uses sudo in several locations to execute commands as other users, most often to execute commands using the Cluster.UserOne and Cluster.UserTwo users. The tomcat user will need all of the following sudo permissions.


User tomcat may run the following commands on this host:

(root) NOPASSWD: /sbin/service tomcat7 restart, /sbin/service tomcat7 stop, /sbin/service tomcat7 start

The following entries are needed only if you are using an SGE backend. Replace /cluster/gridengine-8.1.8/bin/lx-amd64/ in each path with your install directory

(sgeadmin) NOPASSWD: /cluster/gridengine-8.1.8/bin/lx-amd64/qconf, /cluster/gridengine-8.1.8/bin/lx-amd64/qmod

COMPUTE NODE (or head node if you are using a local backend)

User tomcat may run the following commands on this host:

For all of the following, the prefix /export/starexec should be replaced with your configured value of Backend.WorkingDir, and UserOne and UserTwo should be replaced with the values of Cluster.UserOne and Cluster.UserTwo respectively.

(root) NOPASSWD: /bin/chown -R UserOne /export/starexec/sandbox, /bin/chown -R tomcat /export/starexec/sandbox, /bin/chown -R tomcat /export/starexec/sandbox/benchmark, /bin/chown tomcat
(root) NOPASSWD: /bin/chown -R UserTwo /export/starexec/sandbox2, /bin/chown -R tomcat /export/starexec/sandbox2, /bin/chown -R tomcat /export/starexec/sandbox2/benchmark, /bin/chown tomcat

The same applies as on the head node for the following commands

(sgeadmin) NOPASSWD: /cluster/gridengine-8.1.8/bin/lx-amd64/qconf, /cluster/gridengine-8.1.8/bin/lx-amd64/qmod