Update Notes (from Karaf 3.x to 4.x versions)

This section is dedicated to users of previous Apache Karaf version.

Note

For the users upgrading from Karaf 2.x, please see the "Update Notes (from 2.x to 3.x)" in the Karaf 3.x documentation first.
Note

Karaf 4.x supports Java8.

Distributions

Apache Karaf 4.x is available as tar.gz and zip archives. The content is the same and works on either Unix or Windows platforms. The bin folder contains both sh and bat scripts.

Commands

Karaf 4 commands are close to the ones provided in Karaf 3.

The sub-shell modes are the same (in etc/org.apache.karaf.shell.cfg or using shell:completion command).

However, some minor changes have been introduced and new commands available:

Apache Karaf 4.x

feature:requirement-list

feature:requirement-add

feature:requirement-remove

feature:regions

feature:start

feature:stop

jaas:group-create

jaas:group-add

jaas:group-delete

jaas:group-list

jaas:group-role-add

jaas:group-role-delete

jaas:su

jaas:sudo

shell:edit

shell:env

shell:less

shell:stack-traces-print

shell:threads

shell:while

log:list

bundle:capabilities

bundle:diag

bundle:id

bundle:load-test

bundle:requirements

bundle:resolve

system:name

We encourage the users to use the --help option to check the name and type of arguments and options.

In term of development, you can still use the blueprint definition as you do in Karaf 2.x & 3.x (with the corresponding annotations).

However, in Karaf 4.x, you can use DS and new annotations and avoid the usage of a blueprint XML.

The new annotations are available: @Service, @Completion, @Parsing, @Reference. It allows you to completely define the command in the command class directly.

To simplify the generation of the code and OSGi headers, Karaf 4.x provides the karaf-services-maven-plugin (in org.apache.karaf.tooling Maven groupId).

Take a look in the developer guide for the command development "new style" details.

Features repositories

Karaf 4.x provides:

  • mvn:org.apache.karaf.features/enterprise/4.0.x/xml/features

  • mvn:org.apache.karaf.features/framework/4.0.x/xml/features

  • mvn:org.apache.karaf.features/spring/4.0.x/xml/features

  • mvn:org.apache.karaf.features/standard/4.0.x/xml/features

  • mvn:org.apache.karaf.features/static/4.0.x/xml/features

Features resolver

Apache Karaf 4.x brings a complete new feature resolver. The purpose is to simplify the features installation and lifecycle. The new resolver now checks the feature requirements (defined directly in the features XML), and check which bundles provides the capabilities to satisfy these requirements. It allows Karaf to automatically install bundles required by features.

For "old style" feature (features XML using namespace from Karaf 2.x or 3.x), this feature is not enabled. As soon as you use a "new style" feature (with namespace 1.3.0 used by Karaf 4.x), this feature is enabled.

Namespaces

Apache Karaf 4.x brings updated version of the namespaces:

  • Supported features namespaces:

    • karaf-features-1.0.0.xsd

    • karaf-features-1.1.0.xsd

    • karaf-features-1.2.0.xsd

    • karaf-features-1.2.1.xsd

    • karaf-features-1.3.0.xsd

  • Supported jaas namespaces:

    • karaf-jaas-1.0.0.xsd

    • karaf-jaas-1.1.0.xsd

  • Supported shell namespaces:

    • karaf-shell-1.0.0.xsd

    • karaf-shell-1.1.0.xsd

Maven plugin

A cleanup of the goals provided by {{karaf-maven-plugin}} has been done.

Now the provided goals are:

  • karaf:archive to create a tar.gz or zip of a Karaf distribution

  • karaf:assembly to create a custom Karaf distribution assembly

  • karaf:kar to create a kar file

  • karaf:verify to verify and validate Karaf features

  • karaf:features-add-to-repository to recursively copy features XML and content into a folder (repository)

  • karaf:features-export-meta-data to extract the metadata from a features XML

  • karaf:features-generate-descriptor to generate a features XML

  • karaf:commands-generate-help to generate help/documentation on the commands

  • karaf:run to run a Karaf container directly from Maven

  • karaf:client to interact with a remote Karaf instance

  • karaf:deploy to deploy an application to a remote Karaf instance

Update guide

We encourage users to start a fresh Apache Karaf 4.x container.

If you upgrade an existing container, lib and system folder have to be updated (just an override copy).

For the etc folder, a diff is required as some properties have changed and new configurations are available.