WildFly System Properties

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Internal

Overview

System properties can be declared in the server's configuration files and are propagated to the server JVMs and implicitly to applications. For more details on how system property can be declared, see Declaration in Configuration Files below.

Declaration in Configuration Files

Standalone Mode

System properties can be declared in standalone*.xml at the top of the file, conventionally right under the <extensions> element: 

<server ...>
    <extensions>
       ...
    </extensions>

    <system-properties>
        <property name="a.system.property.available.to.the.server.instance" value="some value"/>
    </system-properties>
    ...
</server>

It seems that properties declared this way are not reported in server.log, at least not in EAP 7, under: 

2017-03-27 09:51:02,353 DEBUG [org.jboss.as.config] (MSC service thread 1-6) Configured system properties:
        [Standalone] =
        awt.toolkit = sun.lwawt.macosx.LWCToolkit
        file.encoding = UTF-8
        file.encoding.pkg = sun.io
        ...

Domain Mode

System properties declared as described below are reported in server.log, at least not in EAP 7, unlike in standalone*.xml case.

Declaration in domain.xml

Top Level

System properties can be declared in domain.xml at the top of the file, conventionally right under the <extensions> element: 

<domain ...>
    <extensions>
       ...
    </extensions>

    <system-properties>
        <property name="a.system.property.available.across.the.entire.domain" value="some value"/>
    </system-properties>
    ...
</domain>

These properties are available to all server groups, across the entire domain.

Server Group

<domain ...>
    ...
    <server-groups>
        <server-group name="server-group-one" ...>
            <system-properties>
                <property name="a.system.property.available.only.to.server.group.one" value="some value"/>
            </system-properties>
            ...
        </server-group>
    </server-groups>
</domain>

These properties are only available to servers belonging to the server group the property was declared in.

The fact that we are able to specify different properties (or same properties with different values) for different server groups allows us to use a single profile with multiple server groups, if the differences in configuration between server groups can be expressed as values of system properties. The following example shows how to declare different MDB container pool sizes for servers belonging to two different groups:

Using Same Profile but Different Configuration for Different Server Groups

Declaration in host.xml

System properties can be declared at the top of host.xml, right under the <extensions> element, applying to all servers on that host, as shown below: 

<host ...>
    <extensions>
       ...
    </extensions>

    <system-properties>
        <property name="a.system.property.available.to.servers.on.this.host" value="some value/>
    </system-properties>
    ...
</domain>

or under <servers><server> elements, applying only to the specific servers they are declared for: 

<host ...>
    ...
   <servers>
       <server name="A" group="red">
           <system-properties>
               <property name="a.system.property.available.to.serverA.only" value="something"/>
           </system-properties>
       </server>
   </servers>
</domain>

These properties are available to all servers executing on the host, and are not available to servers executed on other hosts.

System Property Reference in Configuration Files

System property references can be specified in such a way that a default value is provided. The default value is provided if the system property is not defined. 

  ...
  <backup>${jboss.messaging.hornetq.backup:false}</backup>
  ...

System Property Reference in Other System Properties

At least as per EAP 7, referring system properties from custom system properties declared in a <system-properties> block does not seem to work reliably: in the best case, properties are not replaced and left in the ${...} form, and in some cases, referring a property generates a configuration error: 

2017-03-21 13:13:51,332 ERROR [org.jboss.as.host.controller] (Controller Boot Thread) WFLYHC0008: Failed to start server (app01): java.lang.IllegalStateException: WFLYCTL0211: Cannot resolve expression 'includes ${a.domain}'
...
Caused by: org.jboss.as.controller.OperationFailedException: WFLYCTL0211: Cannot resolve expression 'includes ${a.domain}' [ "WFLYCTL0211: Cannot resolve expression 'includes ${a.domain}'" ]
        at org.jboss.as.controller.ExpressionResolverImpl.parseAndResolve(ExpressionResolverImpl.java:282)
        at org.jboss.as.controller.ExpressionResolverImpl.resolveExpressionStringRecursively(ExpressionResolverImpl.java:142)
        at org.jboss.as.controller.ExpressionResolverImpl.resolveExpressionsRecursively(ExpressionResolverImpl.java:84)
        at org.jboss.as.controller.ExpressionResolverImpl.resolveExpressions(ExpressionResolverImpl.java:66)

System Property Management with CLI

Manipulating System Properties

System Properties and Standard Paths

WildFly Standard Paths

Standard System Properties

jboss.qualified.host.name

Relevance: WildFly 9

For a host named "ap1.modcluster.local" it is set to "ap1.modcluster.local"

The value of the first segment of this system property will override the <host> element name attribute in host.xml. For more details see host.xml <host> name.

jboss.host.name

Relevance: WildFly 9

For a host named "ap1.modcluster.local" it is set to "ap1".

The value of this system property will override the <host> element name attribute in host.xml. For more details see host.xml <host> name.

jboss.server.name

Relevance: WildFly 9

For a host named "ap1.modcluster.local" it is set to "ap1"

jboss.node.name

Relevance: WildFly 9

Set externally with -Djboss.node.name in the startup script.

Related:

jboss.server.config.dir

Used by:

jboss.bind.address

Represents the value of the instance's public interface. The default value is 127.0.0.1. Also see

Public Interface Configuration

jboss.bind.address for Standalone Node

One common method of externalizing this operationally is to define it as a system property at the bottom of $JBOSS_HOME/bin/standalone.conf: 

...
JAVA_HOME="${JAVA_HOME} -Djboss.bind.address=192.168.1.15"

The same result can be achieved by specifying the system property as a -D argument for the start script: 

./standalone.sh -Djboss.bind.address=192.168.1.10

jboss.bind.address for Host Controller

One common method to externalize the value operationally for host controllers is to define it as a system property at the bottom of $JBOSS_HOME/bin/domain.conf as follows: 

...
HOST_CONTROLLER_JAVA_OPTS="${HOST_CONTROLLER_JAVA_OPTS} -Djboss.bind.address=1.2.3.4"

The value propagates as system property to the process controller, host controller and servers: 

eap 13556 13457 java -D[Process Controller] ... -Djboss.bind.address=1.2.3.4 ...
eap 13595 13556 java -D[Host Controller] ... -Djboss.bind.address=1.2.3.4 ...
eap 13750 13556 /usr/lib/jvm/java-1.7.0-openjdk-1.7.0.79.x86_64/jre/bin/java -D[Server:ri2] ... -Djboss.bind.address=1.2.3.4 ...

Also see

Public Interface Configuration

jboss.bind.address.management

The value of the instance's management interface bind address. The default value is 127.0.0.1.

jboss.bind.address.management for Standalone Node

One common method of externalizing this operationally is to define it as a system property at the bottom of $JBOSS_HOME/bin/standalone.conf: 

...
JAVA_HOME="${JAVA_HOME} -Djboss.bind.address.management=192.168.1.15"

The same result can be achieved by specifying the system property as a -D argument for the start script: 

./standalone.sh -Djboss.bind.address.management=192.168.1.10

jboss.bind.address.management for Host and Domain Controller

One common method to externalize the value operationally for host and domain controllers is to define it as a system property at the bottom of $JBOSS_HOME/bin/domain.conf as follows: 

...
HOST_CONTROLLER_JAVA_OPTS="${HOST_CONTROLLER_JAVA_OPTS} -Djboss.bind.address.management=1.2.3.4"

Note that an attempt to set jboss.bind.address.management in the <system-properties> section of host.xml did not seem to work.

jboss.bind.address.private

The value to bind the "private" interface to. By default 127.0.0.1.

jboss.bind.address.private for Standalone Node

Define it as a system property at the bottom of $JBOSS_HOME/bin/standalone.conf: 

...
JAVA_HOME="${JAVA_HOME} -Djboss.bind.address.private=192.168.1.15"

The same result can be achieved by specifying the system property as a -D argument for the start script: 

./standalone.sh -Djboss.bind.address.private=192.168.1.10

jboss.bind.address.private for Host Controller

One common method to externalize the value operationally for host controllers is to define it as a system property at the bottom of $JBOSS_HOME/bin/domain.conf as follows: 

...
HOST_CONTROLLER_JAVA_OPTS="${HOST_CONTROLLER_JAVA_OPTS} -Djboss.bind.address.private=1.2.3.4"

The value propagates as system property to the process controller, host controller and servers.

jboss.bind.address.unsecure

The value to bind the "unsecure" interface to. By default 127.0.0.1.

jboss.domain.master.address

The hostname of the domain controller.

It is actually not a good idea to externalize the master domain controller address as a system property. For more explanations see:

Subordinate Host Controller Post-Install

jboss.domain.master.port

The port of the domain controller process.

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