Policies
The following policies are available when you build a virtual application by using Application Pattern Type for Java™: JVM policy, Routing Policy, and Scaling Policy
JVM policy
A Java virtual machine (JVM) policy controls the features and the configuration of the underlying JVM. Attach the JVM policy to configure the Java runtime environment. For example, you can enable IBM® Monitoring and Diagnostic Tools for Java - Health Center, for monitoring the application, and you can debug the application by using an integrated development environment (IDE) such as IBM Rational® Application Developer.
- Set minimum and maximum JVM heap size (in MB)
- Specifies the minimum and maximum heap size of the JVM, in megabytes (MB).
- Enable debug
- Specifies whether the JVM is in debug mode.
- Debug port
- Specifies the port that the JVM uses to listen for remote connections. The default value is 7777. If you select Enable debug but do not specify a value for the debug port, the default value is used.
- Client (IP or IP/netmask)
- Specifies an optional address of the debug client. This setting is used to restrict source access to the debug port. The value is an IP address, for example 1.2.3.4, or a combination of an IP address and netmask, for example 1.2.0.0/255.255.0.0. This example combination of IP address and netmask matches anything in the 1.2. network.
- Enable Health Center
- Specifies whether the JVM is started with the Health Center monitoring agent enabled. The default value is true.
- Health Center port
- Specifies the port that the Health Center agent uses to listen
for remote connections. The default value is 1972.
If you select Enable Health Center but do not
specify a value for the Health Center port, the default value is used.Note: This value specifies the first port that the Health Center agent attempts to use. If the agent cannot use the port, it increments the port number and tries again. For more information, see the Health Center documentation in the IBM Monitoring and Diagnostic Tools for Java documentation.
- Health Center Client (IP or IP/netmask)
- Specifies an optional address of the Health Center client. This setting is used to restrict source access to the Health Center agent port. The value is an IP address, for example, 1.2.3.4, or a combination of an IP address and netmask, for example 1.2.0.0/255.255.0.0. This example combination of IP address and netmask matches anything in the 1.2. network.
- Generic JVM arguments
- Any additional JVM configuration arguments.
The applicable component, which you can attach this policy to, is Java application (IBM Java Runtime Version 7).
When you enable debugging, the JVM is started in debug mode, and is listening on the specified port. A debug program on any client machine can attach to the JVM by default. You can specify a client IP address, or a combination of IP address and netmask, to restrict access to the JVM. A client IP address, such as 10.2.3.5, allows a specific client machine to debug. An IP address and netmask combination, such as 10.2.3.5/255.255.0.0, allows any machine on the specified network, 10.2 in this example, to attach to the JVM.
Routing Policy
The routing policy has the following attributes:
- Type
- Specifies the type of web traffic that is being routed by the HTTP Listener. Currently only HTTP traffic is supported. This attribute is required.
- Virtual Hostname
- Specifies the name of the virtual host for the routing policy. This attribute is required.
- Context Root
- Specifies the context root for the application that is being routed. This attribute is required.
- Use ODR Load Balancer Service
- Check this checkbox to use the ODR Load Balancer Service. Uncheck this box to use Elastic Load Balancer Proxy Service.
Scaling Policy
A Scaling Policy can be assigned to the Java application component. A scaling policy defines the ability for an application to add and remove instances of an application in response to load and responsiveness conditions. Currently only static (manual) scaling is supported.