# System Architecture
Rundeck is a server application you host on a system you designate a central administrative control point. Internally, Rundeck stores job definitions and execution history in a relational database. Output from command and job executions is saved on disk but can be forwarded to remote stores like S3 or Logstash.
Rundeck distributed command execution is performed using a pluggable node execution layer that defaults to SSH but plugins allow you to use other means like MCollective, Salt, WinRM, or your custom method. Rundeck server configuration includes settings to define the outbound user allowed by the remote hosts. Remote machines are not required to make connections back to the server.
The Rundeck application itself is a Java-based webapp. The application provides both graphical interface and network interfaces used by the Rundeck shell tools.
Access to the Rundeck application requires a login and password. The default Rundeck installation uses a flat file user directory containing a set of default logins. Logins are defined in terms of a username and password as well as one or more user groups. An alternative configuration to the flat file user directory, is LDAP (e.g., ActiveDirectory) but Rundeck authentication and authorization is customizable via JAAS. Users must also be authorized to perform actions like define a job or execute one. This is controlled by an access control facility that reads policy files defined by the Rundeck administrator. Privilege is granted if a user's group membership meets the requirements of the policy.
Two installation methods are supported:
System package: RPM and Debian packaging is intended for managed installation and provides robust tools that integrate with your environment, man pages, shell tool set in your path, init.d startup and shutdown.
Launcher: The launcher is intended for quick setup, to get you running right away. Perfect for bootstrapping a project or trying a new feature.
Rundeck can also install as a WAR file into an external container like Tomcat.
Assuming the system requirements are met, Rundeck can be installed either from source, system package or via the launcher.