Red Hat JBoss Enterprise Application Platform Administration I
- Section Running JBoss EAP as a Managed Domain
- Quiz: Managed Domains
- Assigning a Domain Controller
- Guided Exercise: Assigning a Domain Controller
- Configuring a Host Controller
- Guided Exercise: Configuring Host Controllers
- Configuring a Domain Controller
- Quiz: Configuring a Domain Controller
- Lab: Configuring JBoss EAP as a Managed Domain
- Summary
Abstract
| Goal |
Configure JBoss EAP as a Managed Domain |
| Objectives |
|
| Sections |
|
| Lab |
|
To understand Red Hat JBoss Enterprise Application Platform (JBoss EAP) managed domains, you must understand the following terms, and how they relate to each other:
- Domain
A collection of JBoss EAP server instances.
- Host controller
A process running on a host machine that relays configuration information, runtime status, and management commands to JBoss EAP server instances on that particular machine. The host controller is also referred to as a secondary host.
- Domain controller
A single process that acts as the central management control point for a domain. The domain controller is also referred to as the primary host controller.
Warning
You can find documentation, and file names, referring to the primary host controller as master controller, and secondary host controllers as slave controllers. This course uses only the inclusive terms, except to refer to the file names included in JBoss EAP 7.4.
- Server
A JBoss EAP server instance running in its own Java process. It is the application server, that runs application code.
- Process controller
A process running on a host machine that starts host controllers and server instances on that particular machine.
- Host
The set of processes started by the same process controller; a host controller and zero or more application server instances.
- Server group
A collection of servers that are managed and configured as one.
- Profile
A named set of JBoss EAP subsystem configurations.
The following figure helps to visualize the relationships between the above terms:
In the previous figure, the light gray boxes represent machines. They could be either physical or virtual machines, and could run operating systems other than Red Hat Enterprise Linux (RHEL).
Each machine corresponds to a host and runs a process controller, not visible in the figure, and a host controller. Each machine also runs two server instances, but there could be more or less of them.
In a managed domain, one of the host controller instances is configured to act as the central management point, that is, to act as the domain controller. In the previous figure, the host managed by the domain controller does not have any server instances. This is a recommended but NOT required approach because a domain controller is also a host controller that can directly manage its own server instances.
Each host controller interacts with the domain controller to ensure each server instance is configured according to the policies of the domain. All management interfaces, such as the management console and the management CLI communicate to the domain controller only. The management console runs as part of the domain controller operating system processes and JVM.
Any host controller could be configured as a replacement domain controller in case the original one is unavailable, but this promotion is not automated.
A host controller does not perform application server tasks such as serving up Jakarta EE applications and handling client requests. This is done exclusively by server instances. The host controller's sole responsibilities are to interact with the domain controller to help manage the host servers.
Hosts provide a physical grouping that impacts performance metrics such as available processor cores and RAM. Server groups provide a logical grouping that impacts configuration settings; EAP profiles are associated with server groups, not with individual server instances. Applications are also deployed and activated only to server groups and never to individual server instances in a managed domain.
The JBoss EAP managed domain start up script domain.sh starts a host process controller, and the process controller starts the host controller.
Then the host controller requests that the process controller start server instances according to the host configuration.
References
For more information about managed domains, refer to the About Managed Domains section in the Configuration Guide in the in the Red Hat JBoss EAP 7 documentation at https://access.redhat.com/documentation/en-us/red_hat_jboss_enterprise_application_platform/7.4/html-single/configuration_guide/index#about_managed_domains
