Figure : View of the JMX Management Console Web Application

Look at some of the other MBeans and their listed operations; try changing some of the configuration attributes and see what happens. With a very few exceptions, none of the changes made through the console are persistent. The original configuration will be reloaded when you restart JBoss, so you can experiment freely without doing any permanent damage.

Note

If you installed JBoss using the graphical installer, the JMX Console will prompt you for a username and password before you can access it. If you installed using other modes, you can still configure JMX Security manually. We will show you how to secure your console in “Security Service”.

Hot-deployment of services in JBoss

Hot-deployable services are those which can be added to or removed from the running server. These are placed in the JBOSS_DIST/jboss-as/server/<instance-name>/deploy directory. Let’s have a look at a practical example of hot-deployment of services in JBoss before we go on to look at server configuration issues in more detail.

Start JBoss if it isn’t already running and take a look at the server/production/deploy directory. Remove the mail-service.xml file and watch the output from the server:

13:10:05,235 INFO  [MailService] Mail service 'java:/Mail' removed from JNDI

Then replace the file and watch JBoss re-install the service:

13:58:54,331 INFO  [MailService] Mail Service bound to java:/Mail

This is hot-deployment in action.

Basic Configuration Issues

Now that we have examined the JBoss server, we will take a look at some of the main configuration files and what they are used for. All paths are relative to the server configuration directory (server/production, for example).

Core Services

The core services specified in the conf/jboss-service.xml file are started first when the server starts up. If you have a look at this file in an editor you will see MBeans for various services including logging, security, JNDI, JNDIView etc. Try commenting out the entry for the JNDIView service.

Note that because the mbeans definition had nested comments, we had to comment out the mbean in two sections, leaving the original comment as it was.

<!-- Section 1 commented out
<mbean code="org.jboss.naming.JNDIView"
    name="jboss:service=JNDIView"
    xmbean-dd="resource:xmdesc/JNDIView-xmbean.xml">
-->
    <!-- The HANamingService service name -->
<!-- Section two commented out
    <attribute name="HANamingService">jboss:service=HAJNDI</attribute></mbean>
-->
                

If you then restart JBoss, you will see that the JNDIView service no longer appears in the JMX Management Console (JMX Console) listing. In practice, you should rarely, if ever, need to modify this file, though there is nothing to stop you adding extra MBean entries in here if you want to. The alternative is to use a separate file in the deploy directory, which allows your service to be hot deployable.

Logging Service

In JBoss log4j is used for logging. If you are not familiar with the log4j package and would like to use it in your applications, you can read more about it at the Jakarta web site (http://jakarta.apache.org/log4j/).

Logging is controlled from a central conf/jboss-log4j.xml file. This file defines a set of appenders specifying the log files, what categories of messages should go there, the message format and the level of filtering. By default, JBoss produces output to both the console and a log file (log/server.log).

There are 5 basic log levels used: DEBUG, INFO, WARN, ERROR and FATAL. The logging threshold on the console is INFO, which means that you will see informational messages, warning messages and error messages on the console but not general debug messages. In contrast, there is no threshold set for the server.log file, so all generated logging messages will be logged there.

If things are going wrong and there doesn’t seem to be any useful information in the console, always check the server.log file to see if there are any debug messages which might help you to track down the problem. However, be aware that just because the logging threshold allows debug messages to be displayed, that doesn't mean that all of JBoss will produce detailed debug information for the log file. You will also have to boost the logging limits set for individual categories. Take the following category for example.

<!-- Limit JBoss categories to INFO --> 
<category name="org.jboss"> 
    <priority value="
                        INFO

                     "/> 
</category>    

This limits the level of logging to INFO for all JBoss classes, apart from those which have more specific overrides provided. If you were to change this to DEBUG, it would produce much more detailed logging output.

As another example, let’s say you wanted to set the output from the container-managed persistence engine to DEBUG level and to redirect it to a separate file, cmp.log, in order to analyze the generated SQL commands. You would add the following code to the conf/jboss-log4j.xml file:

<appender name="CMP" class="org.jboss.logging.appender.RollingFileAppender"> 
    <errorHandler class="org.jboss.logging.util.OnlyOnceErrorHandler"/> 
    <param name="File" value="${jboss.server.home.dir}/log/cmp.log"/> 
    <param name="Append" value="false"/> 
    <param name="MaxFileSize" value="500KB"/> 
    <param name="MaxBackupIndex" value="1"/> 
 
    <layout class="org.apache.log4j.PatternLayout"> 
        <param name="ConversionPattern" value="%d %-5p [%c] %m%n"/> 
    </layout> 
</appender> 
<category name="org.jboss.ejb.plugins.cmp"> 
    <priority value="DEBUG" /> 
    <appender-ref ref="CMP"/> 
</category> 

This creates a new file appender and specifies that it should be used by the logger (or category) for the package org.jboss.ejb.plugins.cmp.

The file appender is set up to produce a new log file every day rather than producing a new one every time you restart the server or writing to a single file indefinitely. The current log file is cmp.log. Older files have the date they were written added to their filenames. Please note that the log directory also contains HTTP request logs which are produced by the web container.

Security Service

The security domain information is stored in the file conf/login-config.xml as a list of named security domains, each of which specifies a number of JAAS ^[1] login modules which are used for authentication purposes in that domain. When you want to use security in an application, you specify the name of the domain you want to use in the application’s JBoss-specific deployment descriptors, jboss.xml (used in defining jboss specific configurations for an application) and/or jboss-web.xml (used in defining jboss for a Web application. We'll quickly look at how to do this to secure the JMX Console application which ships with JBoss.

Almost every aspect of the JBoss server can be controlled through the JMX Console, so it is important to make sure that, at the very least, the application is password protected. Otherwise, any remote user could completely control your server. To protect it, we will add a security domain to cover the application. This can be done in the jboss-web.xml file for the JMX Console, which can be found in deploy/jmx-console.war/WEB-INF/ directory. Uncomment the security-domain in that file, as shown below.

<jboss-web>
    <security-domain>java:/jaas/jmx-console</security-domain>
</jboss-web>

This links the security domain to the web application, but it doesn't tell the web application what security policy to enforce, what URLs are we trying to protect, and who is allowed to access them. To configure this, go to the web.xml file in the same directory and uncomment the security-constraint that is already there. This security constraint will require a valid user name and password for a user in the JBossAdmin group.

<!-- 
   A security constraint that restricts access to the HTML JMX console
   to users with the role JBossAdmin. Edit the roles to what you want and
   uncomment the WEB-INF/jboss-web.xml/security-domain element to enable
   secured access to the HTML JMX console.
-->
<security-constraint>
    <web-resource-collection>
        <web-resource-name>HtmlAdaptor</web-resource-name>
        <description>
            An example security config that only allows users with the
            role JBossAdmin to access the HTML JMX console web application
        </description>

        <url-pattern>/*</url-pattern>
        <http-method>GET</http-method>
        <http-method>POST</http-method>
    </web-resource-collection>

    <auth-constraint>
        <role-name>JBossAdmin</role-name>
    </auth-constraint>
</security-constraint>

That's great, but where do the user names and passwords come from? They come from the jmx-console security domain we linked the application to. We have provided the configuration for this in the conf/login-config.xml.

<application-policy name="jmx-console">
    <authentication>
        <login-module code="org.jboss.security.auth.spi.UsersRolesLoginModule"
                     flag="required">
            <module-option name="usersProperties">

                props/jmx-console-users.properties
            </module-option>
            <module-option name="rolesProperties">
                props/jmx-console-roles.properties
            </module-option>
        </login-module>
    </authentication> 
</application-policy>

This configuration uses a simple file based security policy. The configuration files are found in the conf/props directory of your server configuration. The usernames and passwords are stored in the conf/props/jmx-console-users.properties file and take the form "username=password". To assign a user to the JBossAdmin group add "username=JBossAdmin" to the jmx-console-roles.properties file (additional roles on that username can be added comma separated). The existing file creates an admin user with the password admin. For security, please either remove the user or change the password to a stronger one.

JBoss will re-deploy the JMX Console whenever you update its web.xml. You can check the server console to verify that JBoss has seen your changes. If you have configured everything correctly and re-deployed the application, the next time you try to access the JMX Console, it will ask you for a name and password. ^[2]

The JMX Console isn't the only web based management interface to JBoss. There is also the Web Console. Although it's a Java applet, the corresponding web application can be secured in the same way as the JMX Console. The Web Console is in the file deploy/management/console-mgr.sar/web-console.war.. The only difference is that the Web Console is provided as a simple WAR file instead of using the exploded directory structure that the JMX Console did. The only real difference between the two is that editing the files inside the WAR file is a bit more cumbersome.

[1]The Java Authentication and Authorization Service. JBoss uses JAAS to provide pluggable authentication modules. You can use the ones that are provided or write your own if you have more specific requirements.