Welcome!

Eclipse Authors: Pat Romanski, Elizabeth White, Liz McMillan, David H Deans, JP Morgenthal

Related Topics: Java IoT, Open Source Cloud, Eclipse

Java IoT: Article

OSGi: An Overview of Its Impact on the Software Lifecycle

Getting ready for OSGi will involve changes to how you write applications and how you deploy and manage those applications

OSGi technology brings a number of much needed benefits to the Java enterprise application market, and is disruptive in that it impacts the software development, deployment, and management practices of many organizations. OSGi impacts deployment given the shared, modular nature of OSGi, meaning application code must be written differently to capitalize on the benefits of OSGi. Equally important, application management processes need to be adjusted, given the highly shared nature of OSGi modules across many applications. This article provides a high-level overview of OSGi, and the impact this framework is having on the software lifecycle.

What Is OSGi?
What started life as an acronym for the telecommunication industry's Open Services Gateway initiative (OSGi) has today expanded to cover Java development across industries and enterprises. Originally conceived and designed as a Java software framework to make it easier to build modular applications able to support always on, constrained environments such as a cell tower switch, OSGi is now being adopted by all the major enterprise Java software providers including all the major Java EE application server vendors (e.g., Oracle, IBM, JBoss). But what prompted the evolution of OSGi? Much like telecommunications services providers, most, if not all, enterprises are running applications or infrastructure that must stay "on" and support dynamic updating of new versions.

The OSGi framework covers three major areas: Bundles, Lifecycle, and Services. The Bundle layer is the most visible, and most used part of the OSGi framework. In short, the Bundle layer is represented as a JAR file (Java ARchive) that includes extra information about which parts of its content can be used by other applications, as well as its dependencies. The Lifecycle layer defines a sequence of steps that the bundles (your code) go through when installed, started, updated, stopped, and uninstalled. Having the lifecycle explicitly defined allows the code in the bundle to start managing its own resources. Equally important, the Lifecycle layer helps administrators catch issues early as OSGi mandates that all external dependencies be resolved before a bundle can be used. If the dependencies cannot be resolved, an error is logged before the bundle starts. Clearly, this is a much better process than getting a phone call in the middle of the night during a critical process run. The Services layer exposes services running code objects that can be called from other code running in the OSGi server. The big difference for OSGi Services is that the framework allows the service implementation to change at runtime - the concept of dynamic updating referenced earlier.

The positive impacts of OSGi on the application development process are clear, but what about application deployment and management? And why is deployment and management even important to the developer?

For more insight into why OSGi (http://www.osgi.org/About/WhyOSGi), and the details of the OSGi specification, you should go to the OSGi Alliance site at http://www.osgi.org.

Impact on Developing Applications
The most visible OSGi change for Java developers is the OSGi Bundle layer. As indicated earlier, this is extra information that is included with the code that explicitly says which Java packages others can use (export), and which Java packages are needed at runtime from others (imports). This additional information allows a developer to be more explicit in code dependencies than ever before, making it significantly easier for teams of developers to work together, and benefitting the overall code maintenance process. In fact, OSGi has been described as providing true Java application modules.

There is also version information about imports and exports, which allows multiple versions of Java libraries (e.g., hibernate or log4j) to be deployed on the same server at the same time and not cause of the traditional conflicts which developers encountered.

As developers get more sophisticated with OSGi, they will better understand the critical importance of the Lifecycle layer. At the most basic, it's a great place to get (start) and release (stop) external resources such as database connections. This eliminates the need to generate the often complicated code required to safely manage connections in the middle of your code.

Some will eventually look at the OSGi Service layer; most to access existing capabilities such as configuration management and logging. Some will share and consume code in different bundles (modules) using OSGi services to take full advantage of runtime versioning of components. Imagine the ability to install a patch to an application module in a running system without needing to write lots of fancy code into your application. That's what OSGi services offer the enterprise developer.

Deploying an OSGi Application
We've already talked about developers putting dependency information into their code bundles, streamlining the deployment process. When you install an OSGi bundle into a server, you can ask the server if all of the dependencies are present, what those dependencies are, and if some are missing, what (and what versions) are missing. All this dependency checking happens before the code is started, so you can catch issues early (before you pager goes off). It also enables the ability to record the full dependency tree, including versions, of an application at any point so you can better track changes to your system and how that relates to application changes.

Several OSGi servers, such as Apache ServiceMix (http://servicemix.apache.org) or the productized distribution Fuse ESB (http://fusesource.com), allow OSGi bundles to be installed and upgraded from Apache Maven repositories. Maven is a build system that can keep software artifacts within a set of locations (repositories) with a number of build time advantages for automatically downloading all dependent code libraries such that a code build can run. For deployment teams, this allows for much closer coordination between themselves and the development team as all team members are working against a common repository. This allows deployment teams to update running systems with a single command once a patch has passed all QA tests.

Managing an OSGi Application
One of the biggest advantages, and potential challenges, for managing an OSGi-based application is the amount of code (bundle) sharing between applications. This can present a challenge for traditional management processes as extra consideration must be given to updating a bundle. For example, how will one update impact other bundle(s)? The good news is that there are a growing number of tools for OSGi that make it much easier to understand the dependencies, and the potential impact, of updating or removing code bundles from a system.

Another advantage of OSGi-based applications is the ability to leverage the OSGi Configuration Admin service, which allows systems administrators to package, change and audit changes to the configuration of bundle properties. For example, the host name and port of the database that a given bundle should access can be managed as OSGi configuration properties giving the administrator a common way to see those properties, make runtime changes, and audit changes.

Summary
This article provides a high-level overview of the impact of OSGi to the enterprise software development, deployment, and management lifecycle. The impact of OSGi across the software development lifecycle means that applications can be more robust and dynamic than ever before, including to the ability to develop and deploy applications that never, ever are unavailable. Getting ready for OSGi will involve changes to how you write applications and how you deploy and manage those applications, so try to think of both technology and process changes as you learn more about OSGi.

More Stories By Scott Cranton

Scott Cranton is a Principle Solutions Engineer at 
FuseSource (http://fusesource.com). He is a veteran in the enterprise software field with more than 20 years of experience as an architect, consultant, and product manager. Scott has worked with many Fortune 100 enterprises in many industries, including Telecommunications, Financial Services, Energy, and Retail.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


IoT & Smart Cities Stories
Dynatrace is an application performance management software company with products for the information technology departments and digital business owners of medium and large businesses. Building the Future of Monitoring with Artificial Intelligence. Today we can collect lots and lots of performance data. We build beautiful dashboards and even have fancy query languages to access and transform the data. Still performance data is a secret language only a couple of people understand. The more busine...
Nicolas Fierro is CEO of MIMIR Blockchain Solutions. He is a programmer, technologist, and operations dev who has worked with Ethereum and blockchain since 2014. His knowledge in blockchain dates to when he performed dev ops services to the Ethereum Foundation as one the privileged few developers to work with the original core team in Switzerland.
René Bostic is the Technical VP of the IBM Cloud Unit in North America. Enjoying her career with IBM during the modern millennial technological era, she is an expert in cloud computing, DevOps and emerging cloud technologies such as Blockchain. Her strengths and core competencies include a proven record of accomplishments in consensus building at all levels to assess, plan, and implement enterprise and cloud computing solutions. René is a member of the Society of Women Engineers (SWE) and a m...
Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life settlement products to hedge funds and investment banks. After, he co-founded a revenue cycle management company where he learned about Bitcoin and eventually Ethereal. Andrew's role at ConsenSys Enterprise is a mul...
Whenever a new technology hits the high points of hype, everyone starts talking about it like it will solve all their business problems. Blockchain is one of those technologies. According to Gartner's latest report on the hype cycle of emerging technologies, blockchain has just passed the peak of their hype cycle curve. If you read the news articles about it, one would think it has taken over the technology world. No disruptive technology is without its challenges and potential impediments t...
If a machine can invent, does this mean the end of the patent system as we know it? The patent system, both in the US and Europe, allows companies to protect their inventions and helps foster innovation. However, Artificial Intelligence (AI) could be set to disrupt the patent system as we know it. This talk will examine how AI may change the patent landscape in the years to come. Furthermore, ways in which companies can best protect their AI related inventions will be examined from both a US and...
In his general session at 19th Cloud Expo, Manish Dixit, VP of Product and Engineering at Dice, discussed how Dice leverages data insights and tools to help both tech professionals and recruiters better understand how skills relate to each other and which skills are in high demand using interactive visualizations and salary indicator tools to maximize earning potential. Manish Dixit is VP of Product and Engineering at Dice. As the leader of the Product, Engineering and Data Sciences team at D...
Bill Schmarzo, Tech Chair of "Big Data | Analytics" of upcoming CloudEXPO | DXWorldEXPO New York (November 12-13, 2018, New York City) today announced the outline and schedule of the track. "The track has been designed in experience/degree order," said Schmarzo. "So, that folks who attend the entire track can leave the conference with some of the skills necessary to get their work done when they get back to their offices. It actually ties back to some work that I'm doing at the University of San...
When talking IoT we often focus on the devices, the sensors, the hardware itself. The new smart appliances, the new smart or self-driving cars (which are amalgamations of many ‘things'). When we are looking at the world of IoT, we should take a step back, look at the big picture. What value are these devices providing. IoT is not about the devices, its about the data consumed and generated. The devices are tools, mechanisms, conduits. This paper discusses the considerations when dealing with the...
Bill Schmarzo, author of "Big Data: Understanding How Data Powers Big Business" and "Big Data MBA: Driving Business Strategies with Data Science," is responsible for setting the strategy and defining the Big Data service offerings and capabilities for EMC Global Services Big Data Practice. As the CTO for the Big Data Practice, he is responsible for working with organizations to help them identify where and how to start their big data journeys. He's written several white papers, is an avid blogge...