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Chapter 2. Applying Hotfix Patch to Fuse on Apache Karaf
2.1. Patching Features and Bundles
Patches are ZIP archives that contain the updated versions of files present in Fuse on Apache Karaf installation. These include:
- Bundles: These are the most common and in the simplest case, hotfix patch may include single bundle.
Configuration files and scripts that are present respectively in
Libraries that are not ordinary bundles and reside in
Feature definition changes: Normally Karaf features are included in descriptors available in the
$FUSE_HOME/systemdirectory, but hotfix patches do not change these files. Instead, hot fix patch may alter feature override file which is
$FUSE_HOME/etc/org.apache.karaf.features.xml. This allows you to alter feature definitions in hotfix manner by upgrading given feature’s bundles or even make given feature use additional bundle.
Difference between Upgrading and Hotfix Patches
- Hotfix Patch: A hotfix patch contains fixes for only one or more critical bugs. These are intended to be applied on top of your current Red Hat Fuse distribution. Its main purpose is to update some of the bundles and librabies in an existing distribution.
- Upgrading: The Fuse on Apache Karaf upgrade mechanism enables you apply fixes to an Apache Karaf container without needing to reinstall an updated version of Fuse on Karaf. It also allows you to roll back the upgrade, if the upgrade causes problems with your deployed applications. The Fuse on Apache Karaf upgrade process updates any files, including bundle JARs, configuration files, and any static files.
For Fuse on Apache Karaf Standalone you can apply the patch using commands from the Karaf console’s patch shell. This approach is non-destructive and reversible. Following procedure can also be used for upgrading Red Hat Fuse on Apache Karaf. For more information of upgrading see Upgrading Fuse on Apache Karaf.
2.2. Applying a Hotfix Patch to Red Hat Fuse on Apache Karaf
You can use the hotfix mechanism to update the available feature definitions and bundles at the same time. The procedure to apply a hotfix patch to the Fuse on Apache Karaf installation is as follows.
- Download the required patch from the Customer Portal.
- Make a full backup of your Fuse on Apache Karaf installation before upgrading.
Open the terminal and start Fuse on Apache karaf server.
[user@FUSE_HOME/bin ~] $ ./fuse
Add the patch to the container’s environment by entering the
patch:addcommand. For example, to add the patch-xxx.zip patch file, enter:
karaf@root()> patch:add 'file:///Downloads/patch-xxx.zip' [name] [installed] [rollup] [description] my-patch-x false false my-patch-x
Simulate installing the patch by entering the
This generates a log of the changes that will be made to the container when the patch is installed, but will not make any actual changes to the container. Review the simulation log to understand these changes.
patch:listcommand to view a list of added patches. In this list, the entries under the [name] heading are patch IDs.
patch:list [name] [installed] [description] my-patch-x false
Apply a patch to the container by entering the
patch:installcommand and specifying the patch ID for the patch that you want to apply.
2.3. Rolling back a Patch
You can rollback the installed hotfix patch and restore it to pre-patch behavior using the
patch:rollback command, as follows:
patch:listcommand to obtain the patch ID of the most recently installed patch.
To rollback the updated bundle enter the following command:
karaf@root()> patch:rollback my-patch-x INFO : org.jboss.fuse.modules.patch.patch-management (2): Rolling back non-rollup patch "my-patch-x" removing overriden feature: hawtio-rbac/2.0.0.fuse-000117 refreshing features Enter feature:info command to view the information about the feature.
karaf@root()> feature:info hawtio-rbac Feature hawtio-rbac 2.0.0.fuse-000117 Details: Installs the hawtio RBAC enabler bundle(s) Feature has no configuration Feature has no configuration files Feature has no dependencies. Feature contains followed bundles: mvn:io.hawt/hawtio-osgi-jmx/2.0.0.fuse-000117 Feature has no conditionals.