server: Server tag configuration

The <server> tag configures a JVM instance in a cluster. It configures HTTP and cluster sockets, keepalives and timeouts, thread pooling, load balancing, and JVM arguments.

<user-name> configures the operating system user Resin should run as. Since the HTTP port 80 is protected in Unix, the web server needs to start as root to bind to port 80. For security, Resin should switch to a non-root user after binding to port 80.

resin.xml with user-name

<resin xmlns="http://caucho.com/ns/resin">
  <cluster id="app-tier">

    <server-default>
      <http port="80"/>

      <user-name>resin</user-name>
    </server-default>

    <server id="web-a"/>
    ...
  </cluster>
</resin>

<group-name> configures the operating system group Resin should run as. Since the HTTP port 80 is protected in Unix, the web server needs to start as root to bind to port 80. For security, Resin should switch to a non-root user after binding to port 80.

resin.xml with user-name

<resin xmlns="http://caucho.com/ns/resin">
  <cluster id="app-tier">

    <server-default>
      <http port="80"/>

      <user-name>resin</user-name>
      <group-name>www</group-name>
    </server-default>

    <server id="web-a"/>
    ...
  </cluster>
</resin>

The <watchdog-arg> configures arguments for the watchdog process. The watchdog improves reliability by monitoring the Resin instance, restarting it if necessary.

The <watchdog-arg> typically is used to enable jconsole for the watchdog JVM.

resin.xml

<resin xmlns="http://caucho.com/ns/resin">
  <cluster id="app-tier">
    <server-default>

      <watchdog-arg>-Dcom.sun.management.jmxremote</watchdog-arg>

    </server-default>

    ...
       
  </cluster>
</resin>

<watchdog-port> configures the administration port for the watchdog JVM. The watchdog launches the server JVM and monitors its health, restarting the JVM when necessary to improve site reliability. The command line arguments use the watchdog-port for the "start" and "stop" commands to tell the watchdog to start and stop the server JVM. The administration also uses the watchdog port for watchdog administration.

The watchdog port will use the same <address> as the server, so it will always be an internal network address, never an external internet address.

server: server tag configuration

<user-name>

<group-name>

<watchdog-arg>

<watchdog-port>