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Chapter 3. Configuring the JBoss EAP for OpenShift Image for Your Java Application
The JBoss EAP for OpenShift image is preconfigured for basic use with your Java applications. However, you can configure the JBoss EAP instance inside the image. The recommended method is to use the OpenShift S2I process, together with application template parameters and environment variables.
Any configuration changes made on a running container will be lost when the container is restarted or terminated.
This includes any configuration changes made using scripts that are included with a traditional JBoss EAP installation, for example add-user.sh
or the management CLI.
It is strongly recommended that you use the OpenShift S2I process, together with application template parameters and environment variables, to make any configuration changes to the JBoss EAP instance inside the JBoss EAP for OpenShift image.
3.1. How the JBoss EAP for OpenShift S2I Process Works 复制链接链接已复制到粘贴板!
The variable EAP_HOME
is used to denote the path to the JBoss EAP installation inside the JBoss EAP for OpenShift image.
The S2I process for JBoss EAP for OpenShift works as follows:
If a
pom.xml
file is present in the source code repository, a Maven build process is triggered that uses the contents of the$MAVEN_ARGS
environment variable.Although you can specify custom Maven arguments or options with the
$MAVEN_ARGS
environment variable, Red Hat recommends that you use the$MAVEN_ARGS_APPEND
environment variable to do this. The$MAVEN_ARGS_APPEND
variable takes the default arguments from$MAVEN_ARGS
and appends the options from$MAVEN_ARGS_APPEND
to it.By default, the OpenShift profile uses the Maven
package
goal, which includes system properties for skipping tests (-DskipTests
) and enabling the Red Hat GA repository (-Dcom.redhat.xpaas.repo
).NoteTo use Maven behind a proxy on JBoss EAP for OpenShift image, set the
$HTTP_PROXY_HOST
and$HTTP_PROXY_PORT
environment variables. Optionally, you can also set the$HTTP_PROXY_USERNAME
,HTTP_PROXY_PASSWORD
, andHTTP_PROXY_NONPROXYHOSTS
variables.-
The results of a successful Maven build are copied to the
EAP_HOME/standalone/deployments/
directory inside the JBoss EAP for OpenShift image. This includes all JAR, WAR, and EAR files from the source repository specified by the$ARTIFACT_DIR
environment variable. The default value of$ARTIFACT_DIR
is the Maven target directory. -
All files in the
configuration
source repository directory are copied to theEAP_HOME/standalone/configuration/
directory inside the JBoss EAP for OpenShift image. If you want to use a custom JBoss EAP configuration file, it should be namedstandalone-openshift.xml
. -
All files in the
modules
source repository directory are copied to theEAP_HOME/modules/
directory inside the JBoss EAP for OpenShift image.
See Artifact Repository Mirrors for additional guidance on how to instruct the S2I process to utilize the custom Maven artifacts repository mirror.
Using environment variables is the recommended method of configuring the JBoss EAP for OpenShift image. See the OpenShift documentation for instructions on specifying environment variables for application containers and build containers.
For example, you can set the JBoss EAP instance’s management username and password using environment variables when creating your OpenShift application:
Available environment variables for the JBoss EAP for OpenShift image are listed in Reference Information.
3.3. Build Extensions and Project Artifacts 复制链接链接已复制到粘贴板!
The JBoss EAP for OpenShift image extends database support in OpenShift using various artifacts. These artifacts are included in the built image through different mechanisms:
- S2I artifacts that are injected into the image during the S2I process.
- Runtime artifacts from environment files provided through the OpenShift Secret mechanism.
Support for using the Red Hat-provided internal datasource drivers with the JBoss EAP for OpenShift image is now deprecated for JDK 8 image streams. It is recommended that you use JDBC drivers obtained from your database vendor for your JBoss EAP applications.
The following internal datasources are no longer provided with the JBoss EAP for OpenShift JDK 11 image:
- MySQL
- PostgreSQL
For more information about installing drivers, see Modules, Drivers, and Generic Deployments.
For more information on configuring JDBC drivers with JBoss EAP, see JDBC drivers in the JBoss EAP Configuration Guide.
3.3.1. S2I Artifacts 复制链接链接已复制到粘贴板!
The S2I artifacts include modules, drivers, and additional generic deployments that provide the necessary configuration infrastructure required for the deployment. This configuration is built into the image during the S2I process so that only the datasources and associated resource adapters need to be configured at runtime.
See Artifact Repository Mirrors for additional guidance on how to instruct the S2I process to utilize the custom Maven artifacts repository mirror.
3.3.1.1. Modules, Drivers, and Generic Deployments 复制链接链接已复制到粘贴板!
There are a few options for including these S2I artifacts in the JBoss EAP for OpenShift image:
- Include the artifact in the application source deployment directory. The artifact is downloaded during the build and injected into the image. This is similar to deploying an application on the JBoss EAP for OpenShift image.
Include the
CUSTOM_INSTALL_DIRECTORIES
environment variable, a list of comma-separated list of directories used for installation and configuration of artifacts for the image during the S2I process. There are two methods for including this information in the S2I:An
install.sh
script in the nominated installation directory. The install script executes during the S2I process and operates with impunity.install.sh
Script ExampleCopy to Clipboard Copied! Toggle word wrap Toggle overflow The
install.sh
script is responsible for customizing the base image using APIs provided byinstall-common.sh
.install-common.sh
contains functions that are used by theinstall.sh
script to install and configure the modules, drivers, and generic deployments.Functions contained within
install-common.sh
:-
install_modules
-
configure_drivers
install_deployments
Modules
A module is a logical grouping of classes used for class loading and dependency management. Modules are defined in the
EAP_HOME/modules/
directory of the application server. Each module exists as a subdirectory, for exampleEAP_HOME/modules/org/apache/
. Each module directory then contains a slot subdirectory, which defaults to main and contains themodule.xml
configuration file and any required JAR files.For more information about configuring
module.xml
files for MySQL and PostgreSQL JDBC drivers, see the Datasource Configuration Examples in the JBoss EAP Configuration Guide.Example
module.xml
FileCopy to Clipboard Copied! Toggle word wrap Toggle overflow Example
module.xml
File for PostgreSQL DatasourceCopy to Clipboard Copied! Toggle word wrap Toggle overflow Example
module.xml
File for MySQL Connect/J 8 DatasourceCopy to Clipboard Copied! Toggle word wrap Toggle overflow NoteThe ".Z" in
mysql-connector-java-8.0.Z.jar
indicates the version of theJAR
file downloaded. The file can be renamed, but the name must match the name in themodule.xml
file.The
install_modules
function ininstall.sh
copies the respective JAR files to the modules directory in JBoss EAP, along with themodule.xml
.Drivers
Drivers are installed as modules. The driver is then configured in
install.sh
by theconfigure_drivers
function, the configuration properties for which are defined in a runtime artifact environment file.Example
drivers.env
FileCopy to Clipboard Copied! Toggle word wrap Toggle overflow The MySQL and PostgreSQL datasources are no longer provided as pre-configured internal datasources. However, these drivers can still be installed as modules as described in Modules, Drivers, and Generic Deployments.
The mechanism follows the
Derby
driver example and uses S2I artifacts. Create adrivers.env
file for each datasource to be installed.Example
drivers.env
File for MySQL DatasourceCopy to Clipboard Copied! Toggle word wrap Toggle overflow Example
drivers.env
File for PostgreSQL DatasourceCopy to Clipboard Copied! Toggle word wrap Toggle overflow For information about download locations for various drivers, such as MySQL or PostgreSQL, see JDBC Driver Download Locations in the Configuration Guide.
-
Generic Deployments
Deployable archive files, such as JARs, WARs, RARs, or EARs, can be deployed from an injected image using the install_deployments
function supplied by the API in install-common.sh
.
If the
CUSTOM_INSTALL_DIRECTORIES
environment variable has been declared but noinstall.sh
scripts are found in the custom installation directories, the following artifact directories will be copied to their respective destinations in the built image:-
modules/*
copied to$JBOSS_HOME/modules/system/layers/openshift
-
configuration/*
copied to$JBOSS_HOME/standalone/configuration
-
deployments/*
copied to$JBOSS_HOME/standalone/deployments
This is a basic configuration approach compared to the
install.sh
alternative, and requires the artifacts to be structured appropriately.-
3.3.2. Runtime Artifacts 复制链接链接已复制到粘贴板!
3.3.2.1. Datasources 复制链接链接已复制到粘贴板!
There are three types of datasources:
- Default internal datasources. These are PostgreSQL, MySQL, and MongoDB. These datasources are available on OpenShift by default through the Red Hat Registry and do not require additional environment files to be configured for JDK 8 image streams. Set the DB_SERVICE_PREFIX_MAPPING environment variable to the name of the OpenShift service for the database to be discovered and used as a datasource.
- Other internal datasources. These are datasources not available by default through the Red Hat Registry but run on OpenShift. Configuration of these datasources is provided by environment files added to OpenShift Secrets.
- External datasources that are not run on OpenShift. Configuration of external datasources is provided by environment files added to OpenShift Secrets.
Example: Datasource Environment File
The DATASOURCES
property is a comma-separated list of datasource property prefixes. These prefixes are then appended to all properties for that datasource. Multiple datasources can then be included in a single environment file. Alternatively, each datasource can be provided in separate environment files.
Datasources contain two types of properties: connection pool-specific properties and database driver-specific properties. Database driver-specific properties use the generic XA_CONNECTION_PROPERTY
, because the driver itself is configured as a driver S2I artifact. The suffix of the driver property is specific to the particular driver for the datasource.
In the above example, ACCOUNTS
is the datasource prefix, XA_CONNECTION_PROPERTY
is the generic driver property, and DatabaseName
is the property specific to the driver.
The datasources environment files are added to the OpenShift Secret for the project. These environment files are then called within the template using the ENV_FILES
environment property, the value of which is a comma-separated list of fully qualified environment files as shown below.
{ “Name”: “ENV_FILES”, “Value”: “/etc/extensions/datasources1.env,/etc/extensions/datasources2.env” }
{
“Name”: “ENV_FILES”,
“Value”: “/etc/extensions/datasources1.env,/etc/extensions/datasources2.env”
}
3.3.2.2. Resource Adapters 复制链接链接已复制到粘贴板!
Configuration of resource adapters is provided by environment files added to OpenShift Secrets.
Attribute | Description |
---|---|
PREFIX_ID | The identifier of the resource adapter as specified in the server configuration file. |
PREFIX_ARCHIVE | The resource adapter archive. |
PREFIX_MODULE_SLOT |
The slot subdirectory, which contains the |
PREFIX_MODULE_ID | The JBoss Module ID where the object factory Java class can be loaded from. |
PREFIX_CONNECTION_CLASS | The fully qualified class name of a managed connection factory or admin object. |
PREFIX_CONNECTION_JNDI | The JNDI name for the connection factory. |
PREFIX_PROPERTY_ParentDirectory | Directory where the data files are stored. |
PREFIX_PROPERTY_AllowParentPaths |
Set |
PREFIX_POOL_MAX_SIZE | The maximum number of connections for a pool. No more connections will be created in each sub-pool. |
PREFIX_POOL_MIN_SIZE | The minimum number of connections for a pool. |
PREFIX_POOL_PREFILL | Specifies if the pool should be prefilled. Changing this value requires a server restart. |
PREFIX_POOL_FLUSH_STRATEGY |
How the pool should be flushed in case of an error. Valid values are: |
The RESOURCE_ADAPTERS
property is a comma-separated list of resource adapter property prefixes. These prefixes are then appended to all properties for that resource adapter. Multiple resource adapter can then be included in a single environment file. In the example below, MYRA
is used as the prefix for a resource adapter. Alternatively, each resource adapter can be provided in separate environment files.
Example: Resource Adapter Environment File
The resource adapter environment files are added to the OpenShift Secret for the project namespace. These environment files are then called within the template using the ENV_FILES
environment property, the value of which is a comma-separated list of fully qualified environment files as shown below.
{ "Name": "ENV_FILES", "Value": "/etc/extensions/resourceadapter1.env,/etc/extensions/resourceadapter2.env" }
{
"Name": "ENV_FILES",
"Value": "/etc/extensions/resourceadapter1.env,/etc/extensions/resourceadapter2.env"
}
3.4.1. Scaling Up and Persistent Storage Partitioning 复制链接链接已复制到粘贴板!
There are two methods for deploying JBoss EAP with persistent storage: single-node partitioning, and multi-node partitioning.
Single-node partitioning stores the JBoss EAP data store directory, including transaction data, in the storage volume.
Multi-node partitioning creates additional, independent split-n
directories to store the transaction data for each JBoss EAP pod, where n
is an incremental integer. This communication is not altered if a JBoss EAP pod is updated, goes down unexpectedly, or is redeployed. When the JBoss EAP pod is operational again, it reconnects to the associated split directory and continues as before. If a new JBoss EAP pod is added, a corresponding split-n
directory is created for that pod.
To enable the multi-node configuration you must set the SPLIT_DATA
parameter to true
. This results in the server creating independent split-n
directories for each instance within the persistent volume which are used as their data store.
This is now the default setting in the eap72-tx-recovery-s2i
template.
Due to the different storage methods of single-node and multi-node partitioning, changing a deployment from single-node to multi-node results in the application losing all data previously stored in the data directory, including messages, transaction logs, and so on. This is also true if changing a deployment from multi-node to single-node, as the storage paths will not match.
3.4.2. Scaling Down and Transaction Recovery 复制链接链接已复制到粘贴板!
When the JBoss EAP for OpenShift image is deployed using a multi-node configuration, it is possible for unexpectedly terminated transactions to be left in the data directory of a terminating pod if the cluster is scaled down.
In order to prevent transactions from remaining within the data store of the terminating pod until the cluster next scales up, the eap72-tx-recovery-s2i
JBoss EAP template creates a second deployment containing a migration pod that is responsible for managing the migration of transactions. The migration pod scans each independent split-n
directory within the JBoss EAP persistent volume, identifies data stores associated with the pods that are terminating, and continues to run until all transactions on the terminating pod are completed.
Since the persistent volume needs to be accessed in read-write mode by both the JBoss EAP application pod and the migration pod, it needs to be created with the ReadWriteMany
access mode. This access mode is currently only supported for persistent volumes using GlusterFS
and NFS
plug-ins. For details, see the Supported Access Modes for Persistent Volumes table.
For more information, see Example Workflow: Automated Transaction Recovery Feature When Scaling Down a Cluster, which demonstrates the automated transaction recovery feature of the JBoss EAP for OpenShift image when scaling down a cluster.