11. Deploying Applications on Application Servers

The assumption is that the JBoss ON agent and resources like a JBoss server or Tomcat server run as the same system user. This allows the agent and the application server itself to manage resource content and configuration simultaneously.

However, if the agent user is different than the resource user, then there can be problems when one entity makes a configuration change and the other attempts a change later.

For example, when deploying an application, the deployment operation is initiated by the agent and the content is supplied through the agent, and then the application server completes the actual deployment. When deleting an application, the application server handles the undeployment by itself.

If a WAR file is deployed exploded without a MANIFEST.MF file, the agent creates one when it writes the SHA-256 value for the package. When the JBoss AS server tries to remove the WAR application later (and the JBoss AS user is different than the agent user), then the removal fails. The JBoss AS server cannot delete the MANIFEST.MF file. The agent then rediscovers the application directory and re-initiates the deployment operation for the removed WAR.

This situation can be avoided. If the agent user and resource user are different, then change the system settings: