High Availability, configuration and best practices .. Once a JBoss EAP 6 cluster is configured and started, a web application simply needs to. High availability for web session state via state replication. .. cluster nodes, providing high availability in case the node handling a particular session fails or is lycgodoomcari.gq Selection from JBoss EAP6 High Availability [Book] you know that Packt offers eBook versions of every book published, with PDF and ePub files available?.
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High availability is a system design approach and associated service implementation which ensures that a Leverage the power of JBoss EAP6 to successfully build high-availability clusters quickly and efficiently PDF下载地址( MB). From the basic uses of JBoss EAP6 through to advanced clustering techniques, this book is the perfect way to learn how to achieve a system. delves into the details of clustering JBoss for high availability and load balancing, as well as going into the details of setting up and managing a JBoss domain.
This is done by clicking on Conrm, as shown in the following screenshot: Finally, we can see that the project has started, as shown in the following screenshot: Now, if we check the server output from the console, we can see that clusterdemo1.
Testing Now we can try to access the deployed project to see if it's running correctly. Deployment scanner The standalone mode supports the traditional hot deployment used in the previous versions of JBoss AS. This method lets you put your copied project into a directory, and then JBoss EAP6 will scan the directory periodically to deploy the project copied into it. This function is supported by the deployment-scanner subsystem, which is dened in standalone. We can try to use the deployment scanner to deploy cluster-demo1.
Before that, we need to undeploy this project from the web management console. After the project is undeployed, we can put cluster-demo1.
This is the marker le that is created by the deployment scanner to mark the status of our project. So, it takes the action. If we delete the cluster-demo1. We can see that the cluster-demo1. All the management actions will be translated into the management commands that are encapsulated in the DMR format.
The deployment actions used by the deployment scanner or the management console are all translated into the DMR commands at last.
This means that EAP6 will rst add this project into its scope and then start it. Both the web management console and the command line interface send such kind of DMR commands to the deployment console.
When we deploy a project into a server group, all the servers in this group will get the project deployed. The management console under the domain mode is different from the standalone mode. It's shown in the following screenshot: [ 38 ] For More Information: www. There is a Server: section in the sidebar where we can check all the servers in different server groups.
The marker indicates the running status of each server.
Ports: shows the port offsets of each server. Because these servers are running on the same machine, their ports must be offset to avoid coniction. Prole: shows the proles that the server group is bound to. The servers that belong to the same group have the same colors on the management console.
We can start or stop a server in the management console.
There are two server groups by default. Let's check the main-server-group in the following section.
The main-server-group We can see that the main-server-group includes two servers by default. Let's deploy cluster-demo1. Please make sure that these two servers are started. If they are not, we can use the Start Server function that is provided by the management console. Now let's deploy cluster-demo1.
First, we need to click on the Management Deployments tab that appears on the side bar. Then click on the Content Repository tab, and click on Add. This process is shown in the following screenshot: [ 39 ] For More Information: www.
Then, we can see that the project is deployed into Content Repository. The result is shown in the following screenshot: We can see that the deployment process in the domain mode is different from the standalone mode. We don't directly deploy a project into servers. Instead, we add it into Content Repository rst and then deploy it to a server group. EAP6 will help us to deploy the project to all the servers in the group. Then, we click on Assign Name and select cluster-demo1. This is shown in the following screenshot: [ 41 ] For More Information: www.
Let's verify this. Testing Now let's try to access the two servers. The results are as follows: From the preceding screenshot, we can see that cluster-demo1.
In this section, let's have a brief discussion about CLI usages. Make sure that you have started EAP6 in the standalone mode.
Let's run the CLI command now. Type 'connect' to connect to the server or 'help' for the list of supported commands. You may have noticed that the CLI doesn't ask us to use the administrator account to log in. As we have connected to the text management console, now let's learn some basic commands.
It's similar to the ls command used in the shell environment.
This is similar to a le system and we can use the ls command to check the contents of the resources as if it's a directory. For example, we can check the resources in a subsystem, as shown in the following screenshot: cd We can use the cd command to view resources as if they were directories.
The usage is shown in the following screenshot: As shown in the preceding screenshot, we can use the cd command to traverse the resources. Basic commands The CLI provides a set of basic commands for us to use. We can press the Tab key twice to see a list of these commands, as shown in the following screenshot: [ 44 ] For More Information: www. For example, if we want to understand the usage of connect, we can use the --help option as shown in the following screenshot: Among the basic commands, I want to specically introduce echo-dmr and read-operation because they are the most frequently used ones.
This means that not all classes inside an EAR will necessarily have access to all other classes in the EAR, unless explicit dependencies have been defined. This behavior is controlled via the ear-subdeployments-isolated attribute in the EE subsystem configuration. By default, this is set to false, which allows the sub-deployments to see classes belonging to other sub-deployments within the EAR.
For example, consider the following EAR deployment: example. Similarly, classes from ejb1. If the ear-subdeployments-isolated is set to true, then no automatic module dependencies between the sub-deployments are set up. You must manually set up the dependencies with Class-Path entries or set up explicit module dependencies. This is per the specification. It is also possible to override the ear-subdeployments-isolated element value at a per-deployment level in the jboss-deployment-structure.
Manifest Entries Deployments or, more correctly, modules within a deployment may set up dependencies on other modules by adding a Dependencies: manifest entry. This entry consists of a comma separated list of module names that the deployment requires. The available modules can be seen under the modules directory in the application server distribution. For example, to add a dependency on Javassist and Apache Velocity, you can add a manifest entry as follows: Dependencies: org. If a beans. This is not commonly used.
It is also possible to add module dependencies on other modules inside the deployment using the Class-Path manifest entry. Module dependencies are separated by a comma. This command will also generate a module.
Modules can also be added manually.