Describes the cluster configuration tags.

See Also

• See the index for a list of all the tags.
• See Web Application configuration for web.xml (Servlet) configuration.
• See Environment configuration for resources: classloader, databases, connectors, and resources.
• See Log configuration for access log configuration, java.util.logging, and stdout/stderr logging.

"%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\""

"%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\""

<server>

  <access-log id='log/access.log'>
    <rollover-period>2W</rollover-period>
  </access-log>

 ...

</server>

<cluster>
  <client-live-time>30s</client-live-time>

  <srun id="a" host="192.168.0.1" port="6802" index="1"/>
  <srun id="b" host="192.168.0.2" port="6802" index="2"/>
</cluster>

<host host-name="www.foo.com">
  <host-alias>foo.com</host-alias>
  <host-alias>web.foo.com</host-alias>

  <root-directory>/opt/www/www.foo.com</root-directory>

  <web-app id="/" document-directory="webapps/ROOT">
    
  </web-app>
  ...
</host>

<host regexp="([^.]+)\.foo\.com">
  <host-name>${'${'}host.regexp[1]}.foo.com</host-name>

  <root-directory>/opt/www/www.${'${'}host.regexp[1]}.com</root-directory>

  ...
</host>

host-deploy

Configures a deploy directory for virtual host.

The host-deploy will add an EL variable \${name}, referring to the name of the host jar file.

http

Configures a HTTP port listening for HTTP requests.

When configuring multiple JVMs, each <http> will have a unique <server-id> which allows the -server command-line to select which ports the server should listen to.

The @virtual-host attribute overrides the browser's Host directive, specifying the explicit host and port for request.getServerName() and getServerPort(). It is not used in most virtual host configurations. Only IP-based virtual hosts which wish to ignore the browser's Host will use @virtual-host.

min-free-memory

For reliability, Resin periodically checks the amount of free memory available. When the free memory drops below <min-free-memory>, even after garbage collection, Resin will force a JVM restart.

In general, application developers should use a heap profiler to eliminate memory leaks and OutOfMemoryErrors. Because an OutOfMemoryError can cause severe problems with the application, Resin detects the low memory before those errors can be thrown.

openssl

Configures SSL.

More documentation is available in the Security section.

The mod_ssl documentation for Apache is a good source of information on OpenSSL.

The class that corresponds to <openssl> is com.caucho.vfs.OpenSSLFactory.

persistent-store

Defines the cluster-aware persistent store used for sharing distributed sessions. The allowed types are "jdbc", "cluster" and "file". The "file" type is only recommended in single-server configurations.

The <persistent-store> configuration is in the <server> level because it needs to share update information across the active cluster and the <cluster> definition is at the <server> level. Sessions activate the persistent store with the <use-persistent-store> tag of the <session-config>.

See Persistent sessions for more details.

<resin xmlns="http://caucho.com/ns/resin">
<cluster>
  <server id="a">
    <cluster-port address="192.168.0.1" port="6800"/>
  </server>

  <server id="b">
    <cluster-port address="192.168.0.2" port="6800"/>
  </server>

  <persistent-store type="jdbc">
    <init>
      <data-source>jdbc/session</data-source>

      <max-idle-time>24h</max-idle-time>
    </init>
  </persistent-store>

  <web-app-default>
    <session-config use-persistent-store="true"/>
  </web-app-default>
</cluster>
</resin>

ping

Starts a thread that periodically makes a request to the server, and restarts Resin if it fails. This facility is used to increase server reliability - if there is a problem with the server (perhaps from a deadlock or an exhaustion of resources), the server is restarted.

A failure occurs if a request to the url returns an HTTP status that is not 200.

Since the local process is restarted, it does not make sense to specify a url that does not get serviced by the instance of Resin that has the ping configuration. Most configurations use url's that specify 'localhost' as the host.

This pinging only catches some problems because it's running in the same process as Resin itself. If the entire JDK freezes, this thread will freeze as well. Assuming the JDK doesn't freeze, the PingThread will catch errors like deadlocks.

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

<resin xmlns="http://caucho.com/ns/resin"
       xmlns:resin="http://caucho.com/ns/resin/core">
  ...
  <cluster id="app-tier">
    <ping>
      <url>http://localhost:8080/index.jsp</url>
      <url>http://localhost:8080/webapp/index.jsp</url>
      <url>http://virtualhost/index.jsp</url>
      <url>http://localhost:443/index.jsp</url>

      <sleep-time>5m</sleep-time>
      <try-count>5</try-count>
    
      <!-- a very busy server -->
      <socket-timeout>30s</socket-timeout>
    </ping>
    ...
  </cluster>
</resin>

The class that corresponds to <ping> is com.caucho.server.admin.PingThread.

Mail notification when ping fails

A refinement of the ping facility sends an email when the server is restarted.

<resin xmlns="http://caucho.com/ns/resin"
       xmlns:resin="http://caucho.com/ns/resin/core">
  ...
  <server>
    <ping resin:type="com.caucho.server.admin.PingMailer">
      <url>http://localhost:8080/index.jsp</url>
      <url>http://localhost:8080/webapp/index.jsp</url>

      <mail-to>[email protected]</mail-to>
      <mail-from>[email protected]</mail-from>
      <mail-subject>Resin ping has failed for server ${'${'}server.name}</mail-subject>
    </ping>
    ...
  </server>
</resin>

port

The port tag allows for custom protocols using Resin's thread and connection management.

The custom protocol will extend from com.caucho.server.port.Protocol.

<server>
  <port id="" host="localhost" port="8888">
    <protocol resin:type="example.Magic8BallProtocol"/>
  </port>
</server>

resin

Top-level configuration for the resin.conf file. The <resin> tag needs to specify the Resin namespace, to allow for validation of the configuration file.

The environment of the top-level <resin> is the global classpath. This environment can be important for <log> configuration for threads which run with using only the global class loader. Because the <resin> environment does not have a dynamic class loader, dynamically loaded classes, like custom jars in resin/lib are not available.

<resin xmlns="http://caucho.com/ns/resin">
  <server>
    <http id='' host='*' port='8080'/>

    <resin:import path="app-default.xml"/>

    <host id=""/>
      <web-app id="/"/>
    </host>
  </server>
</resin>

The class that corresponds to this tag is com.caucho.server.resin.ResinServer

root-directory

Specifies the root directory for the <server> and <host> contexts. All EL-style directory paths are relative to the root-directory.

security-manager

Enable the use of the security manager for the JVM.

<resin xmlns="http://caucho.com/ns/resin"
       xmlns:resin="http://caucho.com/ns/resin/core">

  ...
  <security-manager/>
  ...

See also:

• Security Manager

security-provider

Add one or more security providers. Each entry specifies the name of a security provider class. The name is used to instantiate an instance of the object, which is then passed to java.security.Security.

<resin xmlns="http://caucho.com/ns/resin"
       xmlns:resin="http://caucho.com/ns/resin/core">

  ...

  <security-provider>com.sun.net.ssl.internal.ssl.Provider</security-provider>
  <security-provider>example.MyProvider</security-provider>

  ...

server

Main configuration for the server, configuring ports, threads and virtual hosts.

• Common resources for all virtual hosts and web-apps.
• Thread pooling
• HTTP and SRUN/Cluster ports
• Caching
• virtual host configuration and common web-app-default

The <server> will generally contain a <class-loader> configuration which loads the resin/lib jars dynamically, allowing for system-wide jars to be dropped into resin/lib. <server> configures the main dynamic environment. Database pools common to all virtual hosts, for example, should be configured in the <server> block.

The <server> configures the <thread-pool> and a set of <http> and <srun> ports which share the thread pool. Requests received on those ports will use worker threads from the thread pool.

<server>
  ...
  <alternate-session-url-prefix>/~J=</alternate-session-url-prefix>
  ...

The class that corresponds to <server> is com.caucho.server.resin.ServletServer

EL variables and functions

shutdown-wait-max

Configures the maximum time Resin will wait for the server to shutdown gracefully before forcing an exit.

srun

Configures a clustered HMUX listener.

When configuring Resin in a load-balanced cluster, each Resin instance will have its own <srun> configuration, which Resin uses for distributed session management and for the load balancing itself.

When configuring multiple JVMs, each <srun> will have a unique <server-id> which allows the -server command-line to select which ports the server should listen to.

The class that corresponds to <srun> is com.caucho.server.cluster.ClusterPort