Tomcat Architect

Hierarchy of nested tag representing different components in server.xml.

1 <Server>

 2     <Service>

 3         <Connector />

 4         <Connector />

 5         <Engine>

 6             <Host>

 7                 <Context />

 8             </Host>

 9         </Engine>

10     </Service>

11 </Server>

Deployment structure of tomcat

Internal structure of Engine container.

GLOSSARY

Server:  It is not a container, it’s listened by a standalone port.

Listener:  performs actions when some defined events occur

Global Naming Resources: define some initial instance created in JNDI way.

JNDI: Java Naming Directory Interface

Service: it isn’t a container, subcomponents are connectors and engine.

Connector: endpoint by which requests are received and responses are returned.

        HTTP Connector, meeting HTTP protocol , which handle request pipeline from browser;

         AJP Connector, meeting AJP protocol.

Engine: the entry point that processes every request.

Host: configure one more host when cluster deployment is required

Context: represent a web application, a host can deploy one more contexts (web application)

Valve: similar with ‘filter’, it processes common business or print log on processing request pipeline with formatted form. So the instance it works on is only container.

Realm: could be understood as ‘domain or group role’, it restrict access to ‘container’, such as engine, host, context.