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Chapter 14. Provisioning
Apache Karaf supports the provisioning of applications and modules using the concept ofApache KarafFeatures.
14.1. Application
An application consists of all modules, configuration, and transitive applications required for a feature.
14.2. OSGi
Apache Karaf natively supports the deployment of OSGi applications.
An OSGi application is a set of OSGi bundles. An OSGi bundle is a regular jar file, with additional metadata in the jar MANIFEST.
In OSGi, a bundle can depend on other bundles. So, it means that to deploy an OSGi application, you may also need to firstly deploy a lot of other bundles required by the application.
You have to identify the dependant bundles first and install them. These dependency bundles may require other bundles to satisfy their own dependencies.
An application requires configuration. Before starting your application, in addition to the dependency bundles, you have to create or deploy the configuration.
14.3. Feature and resolver
Apache Karaf provides a simple and flexible way to provision applications.
In Apache Karaf, the application provisioning is an Apache Karaf "feature".
A feature describes an application as:
- a name
- a version
- a optional description (eventually with a long description)
- a set of bundles
- optionally a set configurations or configuration files
- optionally a set of dependency features
When you install a feature, Apache Karaf installs all resources described in the feature. Apache Karaf will automatically resolve and install all bundles, configurations, and dependency features described in the feature.
The feature resolver checks the service requirements, and install the bundles providing the services matching the requirements. The default mode enables this behavior only for "new style" features repositories (basically, the features repositories XML with schema equal or greater to 1.3.0). It doesn’t apply for "old style" features repositories (coming from Apache Karaf2 or 3).
You can change the service requirements enforcement mode in etc/org.apache.karaf.features.cfg
file, using the serviceRequirements
property.
serviceRequirements=default
The possible values are:
- disable: service requirements are completely ignored, for both old style and new style features repositories
- default: service requirements are ignored for old style features repositories, and enabled for new style features repositories.
- enforce: service requirements are always verified, for old style and new style features repositories.
Additionally, a feature can also define requirements. In that case,Apache Karafwill automatically add additional bundles or features providing the capabilities to satisfy the requirements.
A feature has a complete lifecycle: install, start, stop, update, uninstall.
14.4. Features repositories
The features are described in a features XML descriptor. This XML file contains the description of a set of features.
A features XML descriptor is named a "features repository". Before being able to install a feature, you have to register the features repository that provides the feature (using feature:repo-add
command or FeatureMBean as described later).
For instance, the following XML file (or "features repository") describes the feature1
and feature2
features:
<features xmlns="http://karaf.apache.org/xmlns/features/v1.3.0"> <feature name="feature1" version="1.0.0"> <bundle>...</bundle> <bundle>...</bundle> </feature> <feature name="feature2" version="1.1.0"> <feature>feature1</feature> <bundle>...</bundle> </feature> </features>
We can note that the features XML has a schema.
The feature1
feature is available in version 1.0.0
, and contains two bundles. The <bundle/>
element contains a URL to the bundle artifact (see [Artifacts repositories and URLs section|urls] for details). If you install the feature1
feature (using feature:install
or the FeatureMBean as described later),{Apache Karaf} will automatically installs the two bundles described. The feature2
feature is available in version 1.1.0
, and contains a reference to the feature1
feature and a bundle. The <feature/>
element contains the name of a feature. A specific feature version can be defined using the version
attribute to the <feature/>
element (<feature version="1.0.0">feature1</feature>
). If the version
attribute is not specified, Apache Karaf will install the latest version available. If you install the feature2
feature (using feature:install
or the FeatureMBean as described later), Apache Karaf will automatically installs feature1
(if it’s not already installed) and the bundle.
A feature repository is registered using the URL to the features XML file.
The features state is stored in the Apache Karaf cache (in the KARAF_DATA
folder). You can restart Apache Karaf, the previously installed features remain installed and available after restart. If you do a clean restart or you delete the Apache Karaf cache (delete the KARAF_DATA
folder), all previously features repositories registered and features installed will be lost: you will have to register the features repositories and install features by hand again. To prevent this behaviour, you can specify features as boot features.
14.5. Boot features
You can describe some features as boot features. A boot feature will be automatically install by Apache Karaf, even if it has not been previously installed using feature:install
or FeatureMBean.
Apache Karaf features configuration is located in the etc/org.apache.karaf.features.cfg
configuration file.
This configuration file contains the two properties to use to define boot features:
-
featuresRepositories
contains a list (comma-separated) of features repositories (features XML) URLs. -
featuresBoot
contains a list (comma-separated) of features to install at boot.
14.6. Features upgrade
You can update a release by installing the same feature (with the same SNAPSHOT version or a different version).
Thanks to the features lifecycle, you can control the status of the feature (started, stopped, etc).
You can also use a simulation to see what the update will do.
14.7. Overrides
Bundles defined in features can be overridden by using a file etc/overrides.properties. Each line in the file defines one override. The syntax is: <bundle-uri>[;range="[min,max)"] The given bundle will override all bundles in feature definitions with the same symbolic name if the version of the override is greater than the version of the overridden bundle and the range matches. If no range is given then compatibility on the micro version level is assumed.
So for example the override mvn:org.ops4j.pax.logging/pax-logging-service/1.8.5 would overide pax-logging-service 1.8.3 but not 1.8.6 or 1.7.0.
14.8. Feature bundles
14.8.1. Start Level
By default, the bundles deployed by a feature will have a start-level equals to the value defined in the etc/config.properties
configuration file, in the karaf.startlevel.bundle
property.
This value can be "overrided" by the start-level
attribute of the <bundle/>
element, in the features XML.
<feature name="my-project" version="1.0.0"> <bundle start-level="80">mvn:com.mycompany.myproject/myproject-dao</bundle> <bundle start-level="85">mvn:com.mycompany.myproject/myproject-service</bundle> </feature>
The start-level attribute insure that the myproject-dao
bundle is started before the bundles that use it.
Instead of using start-level, a better solution is to simply let the OSGi framework know what your dependencies are by defining the packages or services you need. It is more robust than setting start levels.
14.8.2. Simulate, Start and stop
You can simulate the installation of a feature using the -t
option to feature:install
command.
You can install a bundle without starting it. By default, the bundles in a feature are automatically started.
A feature can specify that a bundle should not be started automatically (the bundle stays in resolved state). To do so, a feature can specify the start
attribute to false in the <bundle/>
element:
<feature name="my-project" version="1.0.0"> <bundle start-level="80" start="false">mvn:com.mycompany.myproject/myproject-dao</bundle> <bundle start-level="85" start="false">mvn:com.mycompany.myproject/myproject-service</bundle> </feature>
14.8.3. Dependency
A bundle can be flagged as being a dependency, using the dependency
attribute set to true on the <bundle/>
element.
This information can be used by resolvers to compute the full list of bundles to be installed.
14.9. Dependent features
A feature can depend on a set of other features:
<feature name="my-project" version="1.0.0"> <feature>other</feature> <bundle start-level="80" start="false">mvn:com.mycompany.myproject/myproject-dao</bundle> <bundle start-level="85" start="false">mvn:com.mycompany.myproject/myproject-service</bundle> </feature>
When the my-project
feature is installed, the other
feature will be automatically installed as well.
It’s possible to define a version range for a dependent feature:
<feature name="spring-dm"> <feature version="[2.5.6,4)">spring</feature> ... </feature>
The feature with the highest version available in the range will be installed.
If a single version is specified, the range will be considered open-ended.
If nothing is specified, the highest available will be installed.
To specify an exact version, use a closed range such as [3.1,3.1]
.
14.9.1. Feature prerequisites
A prerequisite feature is a special kind of dependency. If you add the prerequisite
attribute to a dependant feature tag it will force installation and activation of bundles in the dependant feature before installation of the actual feature. This may be useful when bundles in the given feature are not using pre-installed URL such as wrap
or war
.
14.10. Feature configurations
The <config/>
element in a feature XML allows a feature to create and/or populate a configuration (identified by a configuration PID).
<config name="com.foo.bar"> myProperty = myValue </config>
The name
attribute of the <config/>
element corresponds to the configuration PID (see the [Configuration section|configuration] for details).
The installation of the feature will have the same effect as dropping a file named com.foo.bar.cfg
in the etc
folder.
The content of the <config/>
element is a set of properties, following the key=value standard.
14.11. Feature configuration files
Instead of using the <config/>
element, a feature can specify <configfile/>
elements.
<configfile finalname="/etc/myfile.cfg" override="false">URL</configfile>
Instead of directly manipulating the Apache Karaf configuration layer (as when using the <config/>
element), the <configfile/>
element directly takes a file specified by a URL, and copies the file in the location specified by the finalname
attribute.
If not specified, the location is relative from the KARAF_BASE
variable. It’s also possible to use variable like ${karaf.home}, ${karaf.base}, ${karaf.etc}, or even system properties.
For instance:
<configfile finalname="${karaf.etc}/myfile.cfg" override="false">URL</configfile>
If the file is already present at the desired location it is kept and the deployment of the configuration file is skipped, as a already existing file might contain customization. This behaviour can be overriden by override
set to true.
The file URL is any URL supported by Apache Karaf (see the [Artifacts repositories and URLs|urls] of the user guide for details).
14.11.1. Requirements
A feature can also specify expected requirements. The feature resolver will try to satisfy the requirements. For that, it checks the features and bundles capabilities and will automatically install the bundles to satisfy the requirements.
For instance, a feature can contain:
<requirement>osgi.ee;filter:="(&(osgi.ee=JavaSE)(!(version>=1.8)))"</requirement>
The requirement specifies that the feature will work by only if the JDK version is not 1.8 (so basically 1.7).
The features resolver is also able to refresh the bundles when an optional dependency is satisfy, rewiring the optional import.
14.12. Commands
14.12.1. feature:repo-list
The feature:repo-list
command lists all registered features repository:
karaf@root()> feature:repo-list Repository | URL -------------------------------------------------------------------------------------- org.ops4j.pax.cdi-0.12.0 | mvn:org.ops4j.pax.cdi/pax-cdi-features/0.12.0/xml/features org.ops4j.pax.web-4.1.4 | mvn:org.ops4j.pax.web/pax-web-features/4.1.4/xml/features standard-4.0.0 | mvn:org.apache.karaf.features/standard/4.0.0/xml/features enterprise-4.0.0 | mvn:org.apache.karaf.features/enterprise/4.0.0/xml/features spring-4.0.0 | mvn:org.apache.karaf.features/spring/4.0.0/xml/features
Each repository has a name and the URL to the features XML.
karaf parses the features XML when you register the features repository URL (using feature:repo-add
command or the FeatureMBean as described later). If you want to force Apache Karaf to reload the features repository URL (and so update the features definition), you can use the -r
option:
karaf@root()> feature:repo-list -r Reloading all repositories from their urls Repository | URL -------------------------------------------------------------------------------------- org.ops4j.pax.cdi-0.12.0 | mvn:org.ops4j.pax.cdi/pax-cdi-features/0.12.0/xml/features org.ops4j.pax.web-4.1.4 | mvn:org.ops4j.pax.web/pax-web-features/4.1.4/xml/features standard-4.0.0 | mvn:org.apache.karaf.features/standard/4.0.0/xml/features enterprise-4.0.0 | mvn:org.apache.karaf.features/enterprise/4.0.0/xml/features spring-4.0.0 | mvn:org.apache.karaf.features/spring/4.0.0/xml/features
14.12.2. feature:repo-add
To register a features repository, making new features available in Apache Karaf, you have to use the feature:repo-add
command.
The feature:repo-add
command requires the name/url
argument. This argument accepts:
- a feature repository URL. It’s an URL directly to the features XML file. Any URL described in the [Artifacts repositories and URLs section|urls] of the user guide is supported.
-
a feature repository name defined in the
etc/org.apache.karaf.features.repos.cfg
configuration file.
The etc/org.apache.karaf.features.repos.cfg
defines a list of "pre-installed/available" features repositories:
################################################################################ # # Licensed to the Apache Software Foundation (ASF) under one or more # contributor license agreements. See the NOTICE file distributed with # this work for additional information regarding copyright ownership. # The ASF licenses this file to You under the Apache License, Version 2.0 # (the "License"); you may not use this file except in compliance with # the License. You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. # ################################################################################ # # This file describes the features repository URL # It could be directly installed using feature:repo-add command # enterprise=mvn:org.apache.karaf.features/enterprise/LATEST/xml/features spring=mvn:org.apache.karaf.features/spring/LATEST/xml/features cellar=mvn:org.apache.karaf.cellar/apache-karaf-cellar/LATEST/xml/features cave=mvn:org.apache.karaf.cave/apache-karaf-cave/LATEST/xml/features camel=mvn:org.apache.camel.karaf/apache-camel/LATEST/xml/features camel-extras=mvn:org.apache-extras.camel-extra.karaf/camel-extra/LATEST/xml/features cxf=mvn:org.apache.cxf.karaf/apache-cxf/LATEST/xml/features cxf-dosgi=mvn:org.apache.cxf.dosgi/cxf-dosgi/LATEST/xml/features cxf-xkms=mvn:org.apache.cxf.services.xkms/cxf-services-xkms-features/LATEST/xml activemq=mvn:org.apache.activemq/activemq-karaf/LATEST/xml/features jclouds=mvn:org.apache.jclouds.karaf/jclouds-karaf/LATEST/xml/features openejb=mvn:org.apache.openejb/openejb-feature/LATEST/xml/features wicket=mvn:org.ops4j.pax.wicket/features/LATEST/xml/features hawtio=mvn:io.hawt/hawtio-karaf/LATEST/xml/features pax-cdi=mvn:org.ops4j.pax.cdi/pax-cdi-features/LATEST/xml/features pax-jdbc=mvn:org.ops4j.pax.jdbc/pax-jdbc-features/LATEST/xml/features pax-jpa=mvn:org.ops4j.pax.jpa/pax-jpa-features/LATEST/xml/features pax-web=mvn:org.ops4j.pax.web/pax-web-features/LATEST/xml/features pax-wicket=mvn:org.ops4j.pax.wicket/pax-wicket-features/LATEST/xml/features ecf=http://download.eclipse.org/rt/ecf/latest/site.p2/karaf-features.xml decanter=mvn:org.apache.karaf.decanter/apache-karaf-decanter/LATEST/xml/features
You can directly provide a features repository name to the feature:repo-add
command. For install, to install Apache Karaf Cellar, you can do:
karaf@root()> feature:repo-add cellar Adding feature url mvn:org.apache.karaf.cellar/apache-karaf-cellar/LATEST/xml/features
When you don’t provide the optional version
argument, Apache Karaf installs the latest version of the features repository available. You can specify a target version with the version
argument:
karaf@root()> feature:repo-add cellar 4.0.0.RC1 Adding feature url mvn:org.apache.karaf.cellar/apache-karaf-cellar/4.0.0.RC1/xml/features
Instead of providing a features repository name defined in the etc/org.apache.karaf.features.repos.cfg
configuration file, you can directly provide the features repository URL to the feature:repo-add
command:
karaf@root()> feature:repo-add mvn:org.apache.karaf.cellar/apache-karaf-cellar/4.0.0.RC1/xml/features Adding feature url mvn:org.apache.karaf.cellar/apache-karaf-cellar/4.0.0.RC1/xml/features
By default, the feature:repo-add
command just registers the features repository, it doesn’t install any feature. If you specify the -i
option, the feature:repo-add
command registers the features repository and installs all features described in this features repository:
karaf@root()> feature:repo-add -i cellar
14.12.3. feature:repo-refresh
Apache Karaf parses the features repository XML when you register it (using feature:repo-add
command or the FeatureMBean). If the features repository XML changes, you have to indicate to Apache Karaf to refresh the features repository to load the changes.
The feature:repo-refresh
command refreshes the features repository.
Without argument, the command refreshes all features repository:
karaf@root()> feature:repo-refresh Refreshing feature url mvn:org.ops4j.pax.cdi/pax-cdi-features/0.12.0/xml/features Refreshing feature url mvn:org.ops4j.pax.web/pax-web-features/4.1.4/xml/features Refreshing feature url mvn:org.apache.karaf.features/standard/4.0.0/xml/features Refreshing feature url mvn:org.apache.karaf.features/enterprise/4.0.0/xml/features Refreshing feature url mvn:org.apache.karaf.features/spring/4.0.0/xml/features
Instead of refreshing all features repositories, you can specify the features repository to refresh, by providing the URL or the features repository name (and optionally version):
karaf@root()> feature:repo-refresh mvn:org.apache.karaf.features/standard/4.0.0/xml/features Refreshing feature url mvn:org.apache.karaf.features/standard/4.0.0/xml/features
karaf@root()> feature:repo-refresh cellar Refreshing feature url mvn:org.apache.karaf.cellar/apache-karaf-cellar/LATEST/xml/features
14.12.4. feature:repo-remove
The feature:repo-remove
command removes a features repository from the registered ones.
The feature:repo-remove
command requires a argument:
-
the features repository name (as displayed in the repository column of the
feature:repo-list
command output) -
the features repository URL (as displayed in the URL column of the
feature:repo-list
command output)
karaf@root()> feature:repo-remove karaf-cellar-4.0.0.RC1
karaf@root()> feature:repo-remove mvn:org.apache.karaf.cellar/apache-karaf-cellar/LATEST/xml/features
By default, the feature:repo-remove
command just removes the features repository from the registered ones: it doesn’t uninstall the features provided by the features repository.
If you use -u
option, the feature:repo-remove
command uninstalls all features described by the features repository:
karaf@root()> feature:repo-remove -u karaf-cellar-4.0.0.RC1
14.12.5. feature:list
The feature:list
command lists all available features (provided by the different registered features repositories):
Name | Version | Required | State | Repository | Description ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- pax-cdi | 0.12.0 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Provide CDI support pax-cdi-1.1 | 0.12.0 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Provide CDI 1.1 support pax-cdi-1.2 | 0.12.0 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Provide CDI 1.2 support pax-cdi-weld | 0.12.0 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Weld CDI support pax-cdi-1.1-weld | 0.12.0 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Weld CDI 1.1 support pax-cdi-1.2-weld | 0.12.0 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Weld CDI 1.2 support pax-cdi-openwebbeans | 0.12.0 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | OpenWebBeans CDI support pax-cdi-web | 0.12.0 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Web CDI support pax-cdi-1.1-web | 0.12.0 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Web CDI 1.1 support ...
If you want to order the features by alphabetical name, you can use the -o
option:
karaf@root()> feature:list -o Name | Version | Required | State | Repository | Description ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- deltaspike-core | 1.2.1 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Apache Deltaspike core support deltaspike-data | 1.2.1 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Apache Deltaspike data support deltaspike-jpa | 1.2.1 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Apache Deltaspike jpa support deltaspike-partial-bean | 1.2.1 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Apache Deltaspike partial bean support pax-cdi | 0.12.0 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Provide CDI support pax-cdi-1.1 | 0.12.0 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Provide CDI 1.1 support pax-cdi-1.1-web | 0.12.0 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Web CDI 1.1 support pax-cdi-1.1-web-weld | 0.12.0 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Weld Web CDI 1.1 support pax-cdi-1.1-weld | 0.12.0 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Weld CDI 1.1 support pax-cdi-1.2 | 0.12.0 | | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Provide CDI 1.2 support ...
By default, the feature:list
command displays all features, whatever their current state (installed or not installed).
Using the -i
option displays only installed features:
karaf@root()> feature:list -i Name | Version | Required | State | Repository | Description ------------------------------------------------------------------------------------------------------------------- aries-proxy | 4.0.0 | | Started | standard-4.0.0 | Aries Proxy aries-blueprint | 4.0.0 | x | Started | standard-4.0.0 | Aries Blueprint feature | 4.0.0 | x | Started | standard-4.0.0 | Features Support shell | 4.0.0 | x | Started | standard-4.0.0 | Karaf Shell shell-compat | 4.0.0 | x | Started | standard-4.0.0 | Karaf Shell Compatibility deployer | 4.0.0 | x | Started | standard-4.0.0 | Karaf Deployer bundle | 4.0.0 | x | Started | standard-4.0.0 | Provide Bundle support config | 4.0.0 | x | Started | standard-4.0.0 | Provide OSGi ConfigAdmin support diagnostic | 4.0.0 | x | Started | standard-4.0.0 | Provide Diagnostic support instance | 4.0.0 | x | Started | standard-4.0.0 | Provide Instance support jaas | 4.0.0 | x | Started | standard-4.0.0 | Provide JAAS support log | 4.0.0 | x | Started | standard-4.0.0 | Provide Log support package | 4.0.0 | x | Started | standard-4.0.0 | Package commands and mbeans service | 4.0.0 | x | Started | standard-4.0.0 | Provide Service support system | 4.0.0 | x | Started | standard-4.0.0 | Provide System support kar | 4.0.0 | x | Started | standard-4.0.0 | Provide KAR (KARaf archive) support ssh | 4.0.0 | x | Started | standard-4.0.0 | Provide a SSHd server on Karaf management | 4.0.0 | x | Started | standard-4.0.0 | Provide a JMX MBeanServer and a set of MBeans in wrap | 0.0.0 | x | Started | standard-4.0.0 | Wrap URL handler
14.12.6. feature:install
The feature:install
command installs a feature.
It requires the feature
argument. The feature
argument is the name of the feature, or the name/version of the feature. If only the name of the feature is provided (not the version), the latest version available will be installed.
karaf@root()> feature:install eventadmin
We can simulate an installation using -t
or --simulate
option: it just displays what it would do, but it doesn’t do it:
karaf@root()> feature:install -t -v eventadmin Adding features: eventadmin/[4.0.0,4.0.0] No deployment change. Managing bundle: org.apache.felix.metatype / 1.0.12
You can specify a feature version to install:
karaf@root()> feature:install eventadmin/4.0.0
By default, the feature:install
command is not verbose. If you want to have some details about actions performed by the feature:install
command, you can use the -v
option:
karaf@root()> feature:install -v eventadmin Adding features: eventadmin/[4.0.0,4.0.0] No deployment change. Done.
If a feature contains a bundle which is already installed, by default, Apache Karaf will refresh this bundle. Sometime, this refresh can cause issue to other running applications. If you want to disable the auto-refresh of installed bundles, you can use the -r
option:
karaf@root()> feature:install -v -r eventadmin Adding features: eventadmin/[4.0.0,4.0.0] No deployment change. Done.
You can decide to not start the bundles installed by a feature using the -s
or --no-auto-start
option:
karaf@root()> feature:install -s eventadmin
14.12.7. feature:start
By default, when you install a feature, it’s automatically started. However, you can specify the -s
option to the feature:install
command so that is it not started on installation.
As soon as you install a feature (started or not), all packages provided by the bundles defined in the feature will be available, and can be used for the wiring in other bundles.
When starting a feature, all bundles are started, and so, the feature also exposes the services.
14.12.8. feature:stop
You can also stop a feature: it means that all services provided by the feature will be stop and removed from the service registry. However, the packages are still available for the wiring (the bundles are in resolved state).
14.12.9. feature:uninstall
The feature:uninstall
command uninstalls a feature. As the feature:install
command, the feature:uninstall
command requires the feature
argument. The feature
argument is the name of the feature, or the name/version of the feature. If only the name of the feature is provided (not the version), the latest version available will be installed.
karaf@root()> feature:uninstall eventadmin
The features resolver is involved during feature uninstallation: transitive features installed by the uninstalled feature can be uninstalled themselves if not used by other feature.
14.13. Deployer
You can hot deploy a feature XML by dropping the file directly in the deploy
folder. See Section 4.1, “Hot Deployment”. When you drop a features XML in the deploy folder, the features deployer does: * register the features XML as a features repository * the features with install
attribute set to "auto" will be automatically installed by the features deployer.
For instance, dropping the following XML in the deploy folder will automatically install feature1 and feature2, whereas feature3 won’t be installed:
<?xml version="1.0" encoding="UTF-8"?> <features name="my-features" xmlns="http://karaf.apache.org/xmlns/features/v1.3.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://karaf.apache.org/xmlns/features/v1.3.0 http://karaf.apache.org/xmlns/features/v1.3.0"> <feature name="feature1" version="1.0" install="auto"> ... </feature> <feature name="feature2" version="1.0" install="auto"> ... </feature> <feature name="feature3" version="1.0"> ... </feature> </features>
14.14. JMX FeatureMBean
On the JMX layer, you have a MBean dedicated to the management of the features and features repositories: the FeatureMBean.
The FeatureMBean object name is: org.apache.karaf:type=feature,name=*
.
14.14.1. Attributes
The FeatureMBean provides two attributes:
-
Features
is a tabular data set of all features available. -
Repositories
is a tabular data set of all registered features repositories.
The Repositories
attribute provides the following information:
-
Name
is the name of the features repository. -
Uri
is the URI to the features XML for this repository. -
Features
is a tabular data set of all features (name and version) provided by this features repository. -
Repositories
is a tabular data set of features repositories "imported" in this features repository.
The Features
attribute provides the following information:
-
Name
is the name of the feature. -
Version
is the version of the feature. -
Installed
is a boolean. If true, it means that the feature is currently installed. -
Bundles
is a tabular data set of all bundles (bundles URL) described in the feature. -
Configurations
is a tabular data set of all configurations described in the feature. -
Configuration Files
is a tabular data set of all configuration files described in the feature. -
Dependencies
is a tabular data set of all dependent features described in the feature.
14.14.2. Operations
-
addRepository(url)
adds the features repository with theurl
. Theurl
can be aname
as in thefeature:repo-add
command. -
addRepository(url, install)
adds the features repository with theurl
and automatically installs all bundles ifinstall
is true. Theurl
can be aname
like in thefeature:repo-add
command. -
removeRepository(url)
removes the features repository with theurl
. Theurl
can be aname
as in thefeature:repo-remove
command. -
installFeature(name)
installs the feature with thename
. -
installFeature(name, version)
installs the feature with thename
andversion
. -
installFeature(name, noClean, noRefresh)
installs the feature with thename
without cleaning the bundles in case of failure, and without refreshing already installed bundles. -
installFeature(name, version, noClean, noRefresh) ` installs the feature with the `name
andversion
without cleaning the bundles in case of failure, and without refreshing already installed bundles. -
uninstallFeature(name)
uninstalls the feature with thename
. -
uninstallFeature(name, version)
uninstalls the feature with thename
andversion
.
14.14.3. Notifications
The FeatureMBean sends two kind of notifications (on which you can subscribe and react):
- When a feature repository changes (added or removed).
- When a feature changes (installed or uninstalled).