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From Dario Amiri <dariusham...@hotmail.com>
Subject Re: Levels of Containerization - focus on Docker and Karaf
Date Fri, 13 Jan 2017 19:28:14 GMT
I use Docker and Karaf. I've never had a problem creating a Docker image of my Karaf container.
What I gain is freedom from having to worry about dependency related issues such as whether
the right JRE is available.

That being said there are some challenges when using Karaf to build 12-factor apps. FWIW here's
my two item list of what would make Karaf a more attractive platform from a 12-factor app

1. The ability to inject Karaf configuration through the environment (e.g. environment variables).
Not just a single property, but an entire config admin managed configuration file if necessary.
Even the existing support for reading property values from the environment is cumbersome because
it requires having to setup that relationship as a Java system property as well.

2. The ability to package Karaf as a standalone runnable jar. Looks like Karaf boot is addressing
this. I hope it comes with tooling that makes it easy to transition to this kind of model.


On 01/12/2017 04:44 AM, Nick Baker wrote:

Thanks Guillaume!

This is perfect for our microservice/containerized Karaf. I'll give this a try and see if
we can get our features in startup. We've had issues in the past here.

-Nick Baker

From: Guillaume Nodet <gnodet@apache.org><mailto:gnodet@apache.org>
Sent: Thursday, January 12, 2017 5:55:24 AM
To: user
Subject: Re: Levels of Containerization - focus on Docker and Karaf

Fwiw, starting with Karaf 4.x, you can build custom distributions which are mostly static,
and that more closely map to micro-services / docker images.  The "static" images are called
this way because you they kinda remove all the OSGi dynamism, i.e. no feature service, no
deploy folder, read-only config admin, all bundles being installed at startup time from etc/startup.properties.
This can be easily done by using the karaf maven plugin and configuring startupFeatures and
referencing the static kar, as shown in:

2017-01-11 21:07 GMT+01:00 CodeCola <prasenjit@rogers.com<mailto:prasenjit@rogers.com>>:
Not a question but a request for comments. With a focus on Java.

Container technology has traditionally been messy with dependencies and no
easy failsafe way until Docker came along to really pack ALL dependencies
(including the JVM) together in one ready-to-ship image that was faster,
more comfortable, and easier to understand than other container and code
shipping methods out there. The spectrum from (Classical) Java EE Containers
(e.g. Tomcat, Jetty) --> Java Application Servers that are containerized
(Karaf, Wildfly, etc), Application Delivery Containers (Docker) and
Virtualization (VMWare, Hyper-V) etc. offers a different level of isolation
with different goals (abstraction, isolation and delivery).

What are the choices, how should they play together, should they be used in
conjunction with each other as they offer different kinds of


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Guillaume Nodet
Red Hat, Open Source Integration

Email: <mailto:gnodet@redhat.com> gnodet@redhat.com<mailto:gnodet@redhat.com>
Web: http://fusesource.com<http://fusesource.com/>
Blog: http://gnodet.blogspot.com/

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