You should not have to build a new docker container image for every possible type of configuration. Just look at any standard docker images in the public Docker registry. All configuration is driven from the environment variables. There is a multitude of examples in the public docker registry.
A new implementation of ConfigurationAdmin sounds like a good way to solve the problem. However, I don't have the expertise to build and maintain that on my own. Nor should I because this is an ubiquitous pattern for all Dockerized applications. Karaf should do this out of the box if it wants to play well with Docker. Zookeeper is great, but what about the coordinates to Zookeeper? Where do I configure that? We're back to the same problem. Also, Zookeeper is likely too heavy a solution for some people (me included). D On 01/13/2017 01:13 PM, Nick Baker wrote: Injecting configuration into a containerized app (docker) is considered standard practice. The friction here is the level of sophistication in OSGI Configuration. It seems to me what you need isn't some hack to push configurations through environment variables, but a new implementation of ConfigurationAdmin, or an agent which interacts with CM mirroring configurations in from an external system. In our usage it's common to have a "tenant", think Walmart vs Target. Setting the tenant ID as an environment variable then having the configurations loaded from Zookeeper or whatever, injected into CM seems right. -Nick ________________________________ From: Dario Amiri <[email protected]><mailto:[email protected]> Sent: Friday, January 13, 2017 3:21:17 PM To: [email protected]<mailto:[email protected]> Subject: Re: Levels of Containerization - focus on Docker and Karaf Let me expand on why this is desirable. Without the ability to set configuration through environment variables, I essentially have to create a docker image for each deployment. I have a root Dockerfile which assembles the main Karaf container image and brings in dependencies such as the JRE, then I have a Dockerfile for each deployment environment which builds on top of the root image by overriding deployment specific configuration. Automation reduces this burden but it is not ideal. If I could set the contents of a config file in an environment variable, I could just pass the configuration directly to my root karaf docker image without having to build on top of it. Being able to start Karaf as "java -jar karaf.jar" is desirable because it makes it easier to use a Karaf based application with PaaS such as Heroku and Cloud Foundry. D On 01/13/2017 12:10 PM, Dario Amiri wrote: Ideally, I want to be able to do: java -jar my-karaf.jar And I can override individual configuration files using some environment variable convention. D On 01/13/2017 11:56 AM, Brad Johnson wrote: Does it have to be an executable jar file or just a standalone executable? The static profiles actually create and zip up a full Karaf/felix/dependency/application implementation that when unzipped has all the standard bin directory items. Brad From: Dario Amiri [mailto:[email protected]] Sent: Friday, January 13, 2017 1:28 PM To: [email protected]<mailto:[email protected]> Subject: Re: Levels of Containerization - focus on Docker and Karaf 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 perspective. 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. D 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 <[email protected]><mailto:[email protected]> 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: https://github.com/apache/karaf/blob/master/demos/profiles/static/pom.xml 2017-01-11 21:07 GMT+01:00 CodeCola <[email protected]<mailto:[email protected]>>: 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 Containerization? <http://karaf.922171.n3.nabble.com/file/n4049162/Levels_of_Containerization.png> -- View this message in context: <http://karaf.922171.n3.nabble.com/Levels-of-Containerization-focus-on-Docker-and-Karaf-tp4049162.html> http://karaf.922171.n3.nabble.com/Levels-of-Containerization-focus-on-Docker-and-Karaf-tp4049162.html Sent from the Karaf - User mailing list archive at Nabble.com. -- ------------------------ Guillaume Nodet ------------------------ Red Hat, Open Source Integration Email: <mailto:[email protected]> [email protected]<mailto:[email protected]> Web: http://fusesource.com<http://fusesource.com/> Blog: http://gnodet.blogspot.com/
