Welcome!

OpenStack Journal Authors: Elizabeth White, Liz McMillan, Pat Romanski, Yeshim Deniz, Michael Bushong

Related Topics: Open Source, Linux, Eclipse, Open Web, Apache, OpenStack Journal

Open Source: Article

Which Open Source Software License Should I Use?

There are different considerations for every project

I've recently been involved in several discussions that are variations on, "Which open source or free software license should I choose for my project?" Here is my way of looking at the large and growing collection of licenses in the wild. First let's make sure we all understand that I Am Not A Lawyer. This is not legal advice. Depending upon your needs and your comfort with risk around your software, you'll want to confirm your legal choices with counsel in your jurisdiction.

The first and obvious consideration is whether or not the license is approved as an open source license by the Open Source Initiative (OSI). The OSI created the Open Source Definition in the late 1990s as a set of attributes that a software license must support to be considered "open source". Anyone can take a license to the OSI for debate and discussion and if approved as meeting the OSD, then the license is added to the canonical list.

While this seems an obvious place to start, I was recently surprised to discover a license called the "Clear BSD License." It attempts to clarify explicitly that patents are not being discussed in the license. It is not on the OSI list (while the New BSD and Simplified BSD licenses are) and is therefore not worth considering. Inventing new licenses as small derivatives of existing licenses is not helpful and creates costly legal busy work. There exists a broad collection of OSI-approved licenses today. These licenses cover millions of lines of software involved in billions of dollars in procurement. One would be hard pressed to describe a serious set of circumstances that isn't already covered by an OSI-approved license.

There are several big levers available when considering an open source license:

  • How much license reciprocity is required with respect to the software, modifications, and any derivatives someone develops?
  • What is said about patent licensing and litigation?
  • What legal jurisdiction covers the license?

The reciprocity issue is all about "copyleft" and whether or not using the software source code attaches the license to the modifications and derivatives, and whether the source code to those modifications and derivatives needs to be published.

On one end of the spectrum are licenses that have no copyleft requirements. These licenses essentially allow anyone to use the software in anyway without requiring much more than maintaining copyrights. Licenses that fall into this set include the New and Simplified BSD licenses, the MIT license, and the Apache 2.0 and Microsoft Permissive licenses.

There are a set of licenses that maintain a sense of copyleft around the software itself but support the use of the software in larger works of software which may contain software that is licensed differently (e.g. closed and proprietary). These licenses include the Eclipse Public License, the newer Mozilla Public License 2.0, and the Microsoft Reciprocal License.

On the other end of the copyleft spectrum are strong copyleft licenses. Software freedom is defined by the Free Software Foundation in terms of the freedoms a user of software must have. Strong copyleft supports software freedom. Many developers support software freedom, and demonstrate this support using one of the family of GPL licenses (GPL2.0, GPL3.0, and the Affero GPL3.0) as a way to ensure the strongest copyleft and strongest license attachment when the software in question is used in building and distributing other software.

Software patents weren't really an issue when software was beginning to be widely shared on the early Internet and so weren't mentioned in the early licenses. By the late 1990s, software patents were on the rise and corporate legal teams were becoming more involved in the writing of open source licenses as they became more involved with open source software and developing the open source foundations around evolving projects. The Apache 2.0 License, Mozilla Public License 2.0, Eclipse Public License, the newer GPL licenses, and both Microsoft licenses reflect this shift in language. Each license explicitly talks about patent licenses. Each license has language that covers patent litigation to varying degrees.

I mention legal jurisdiction in the big levers category because some licenses explicitly mention it and this can be a real show stopper for some people. For that reason alone I treat it as a Big Lever. (The Mozilla Public License 2.0 specifically tries to deal with jurisdiction as one of changes from the original MPL, as that was often a criticism of the earlier license.)

Other considerations in license choice include:

  • Are there project specific affinities?
  • History of the license and foundation/corporate/commercial involvement?

The "language" projects (Perl, PHP, Python) each have their own licenses (Artistic License 2.0, PHP License 3.0, and Python License 2.0 respectively). If you are working on a project that closely ties to a specific open source programming language community then you should obviously consider that community's license as the question of mixing modules and dependencies will be simplified with respect to open source license.

As software IP law has evolved and the Internet has become an enormous space for people to collaborate on software development, commercial organizations became involved. We have seen the creation of open source software foundations with specific licenses associated with them. Corporate legal teams have become involved in authoring open source licenses, and the language and structure of these licenses (e.g. terminology and definitions) reflects this involvement. Lawyers without a lot of experience in open source licenses may feel more comfortable reviewing these newer licenses.

So to recap, presuming that your primary motivation is to co-develop and collaborate on an open source project, in my way of looking at open source licenses your choices break down roughly as follows. (I'm keeping the discussion here to widely used licenses, and/or licenses where large commercial organizations with conservative counsel or neutral non-profit open source foundations had a hand in their creation.)

If you want to allow anyone to do anything at any time with the software, use the MIT or new (3-clause) BSD license, i.e. no copyleft and no discussion of patents. Both of these licenses came from the academic world, and both from a period of time where software patents were not a focus.

If you want to allow anyone to do anything with the software (so no copyleft), but feel something needs to be said about patents and license termination in the face of litigation, and/or you want a license that corporate counsel is more comfortable reading then look at either the Apache 2.0 license or possibly the Microsoft Permissive License. These licenses were written to continue to encourage a completely open sharing environment but were written with a more corporate view (note the structure and language), and both begin to cover patents with varying (and subtly different) degrees of patent retaliation built into them.

If you feel others should be able to build [possibly product] around your software, but want to ensure changes to the core software project itself remain open source (i.e. the changes must be published), you likely want to look to either the Eclipse Public License, the newer Mozilla Public License 2.0 or the Microsoft Reciprocal License. These are modern licenses developed from commercial/corporate perspectives supporting "weak" copyleft. [N.B. The EPL does name NY State as the jurisdiction.] Pay attention to patent statements in each.

If you are a firm supporter of software freedom or want to ensure that if your software source is used anywhere that the resulting derivatives are maximally published as open source ensuring software freedom then you should look to GPL2.0 or GPL3.0 depending upon your needs.

There are a couple of interesting side ideas I've come across in the open source licensing space as different projects wrestled with how best to create the "right" licensing for their software.

  • Many companies are concerned about their patent portfolios when creating open source projects. Google took an interesting approach to the problem when they released the WebM project. They chose the New BSD license and then created a very specific "Additional IP Rights Grant" to cover the patent language they needed.
  • It is the nature of IP law that the owner of the property can license it as many ways to as many people as they choose. This is why the Microsoft EULA for a personal copy of the Windows operating system is different from an Enterprise License Agreement and how MySQL AB developed a line of business around closed software licensing as well as their GPL-licensed project. In the early days (up through PHP3), the software from the PHP project was similarly "dual" licensed under both the GPL2.0 and an earlier PHP license to allow the software to be included in as many places as possible because the GPL was not directly compatible with the PHP license of the time.

I have deliberately not tried to create a table or decision tree for license choice here. I believe there are sufficient edges and nuances to license choice that it can never be properly "automated" with the licenses we have today that reflect their rich background of needs and history. There is always one more legal question of "what about the situation when ...?" Such questions will likely involve legal counsel and may be very jurisdiction sensitive.

Likewise, open source software licenses don't simply reflect a set of legal choices. In the early stage of an open source project when the author or authors are first publishing the software, the choice of license reflects as much of the social contract that is being made for the project as any legal requirements. It is the first governance document of the early possible community that comes into play long before formal governance, mission statements, and codes of conduct may be created around growing community.

Full text of all the licenses can be found on the Open Source Initiative at:http://opensource.org/licenses/alphabetical

Excellent information on how to consider various software licenses in combination with the GPL can be found here: http://www.gnu.org/licenses/license-list.html#SoftwareLicenses

If you need to get a lawyer up to speed, consider pointing them to: http://www.ifosslr.org/ifosslr

More Stories By Stephen Walli

Stephen Walli has worked in the IT industry since 1980 as both customer and vendor. He is presently the technical director for the Outercurve Foundation.

Prior to this, he consulted on software business development and open source strategy, often working with partners like Initmarketing and InteropSystems. He organized the agenda, speakers and sponsors for the inaugural Beijing Open Source Software Forum as part of the 2007 Software Innovation Summit in Beijing. The development of the Chinese software market is an area of deep interest for him. He is a board director at eBox, and an advisor at Bitrock, Continuent, Ohloh (acquired by SourceForge in 2009), and TargetSource (each of which represents unique opportunities in the FOSS world). He was also the open-source-strategist-in-residence for Open Tuesday in Finland.

Stephen was Vice-president, Open Source Development Strategy at Optaros, Inc. through its initial 19 months. Prior to that he was a business development manager in the Windows Platform team at Microsoft working on community development, standards, and intellectual property concerns.

Cloud Expo Latest Stories
The 16th International Cloud Expo announces that its Call for Papers is now open. 16th International Cloud Expo, to be held June 9–11, 2015, at the Javits Center in New York City brings together Cloud Computing, APM, APIs, Security, Big Data, Internet of Things, DevOps and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding business opportunity. Submit your speaking proposal today!
14th International Cloud Expo, held on June 10–12, 2014 at the Javits Center in New York City, featured three content-packed days with a rich array of sessions about the business and technical value of cloud computing, Internet of Things, Big Data, and DevOps led by exceptional speakers from every sector of the IT ecosystem. The Cloud Expo series is the fastest-growing Enterprise IT event in the past 10 years, devoted to every aspect of delivering massively scalable enterprise IT as a service.
Hardware will never be more valuable than on the day it hits your loading dock. Each day new servers are not deployed to production the business is losing money. While Moore’s Law is typically cited to explain the exponential density growth of chips, a critical consequence of this is rapid depreciation of servers. The hardware for clustered systems (e.g., Hadoop, OpenStack) tends to be significant capital expenses. In his session at 15th Cloud Expo, Mason Katz, CTO and co-founder of StackIQ, to discuss how infrastructure teams should be aware of the capitalization and depreciation model of these expenses to fully understand when and where automation is critical.
Over the last few years the healthcare ecosystem has revolved around innovations in Electronic Health Record (HER) based systems. This evolution has helped us achieve much desired interoperability. Now the focus is shifting to other equally important aspects – scalability and performance. While applying cloud computing environments to the EHR systems, a special consideration needs to be given to the cloud enablement of Veterans Health Information Systems and Technology Architecture (VistA), i.e., the largest single medical system in the United States.
In his session at 15th Cloud Expo, Mark Hinkle, Senior Director, Open Source Solutions at Citrix Systems Inc., will provide overview of the open source software that can be used to deploy and manage a cloud computing environment. He will include information on storage, networking(e.g., OpenDaylight) and compute virtualization (Xen, KVM, LXC) and the orchestration(Apache CloudStack, OpenStack) of the three to build their own cloud services. Speaker Bio: Mark Hinkle is the Senior Director, Open Source Solutions, at Citrix Systems Inc. He joined Citrix as a result of their July 2011 acquisition of Cloud.com where he was their Vice President of Community. He is currently responsible for Citrix open source efforts around the open source cloud computing platform, Apache CloudStack and the Xen Hypervisor. Previously he was the VP of Community at Zenoss Inc., a producer of the open source application, server, and network management software, where he grew the Zenoss Core project to over 10...
Most of today’s hardware manufacturers are building servers with at least one SATA Port, but not every systems engineer utilizes them. This is considered a loss in the game of maximizing potential storage space in a fixed unit. The SATADOM Series was created by Innodisk as a high-performance, small form factor boot drive with low power consumption to be plugged into the unused SATA port on your server board as an alternative to hard drive or USB boot-up. Built for 1U systems, this powerful device is smaller than a one dollar coin, and frees up otherwise dead space on your motherboard. To meet the requirements of tomorrow’s cloud hardware, Innodisk invested internal R&D resources to develop our SATA III series of products. The SATA III SATADOM boasts 500/180MBs R/W Speeds respectively, or double R/W Speed of SATA II products.
As more applications and services move "to the cloud" (public or on-premise) cloud environments are increasingly adopting and building out traditional enterprise features. This in turn is enabling and encouraging cloud adoption from enterprise users. In many ways the definition is blurring as features like continuous operation, geo-distribution or on-demand capacity become the norm. NuoDB is involved in both building enterprise software and using enterprise cloud capabilities. In his session at 15th Cloud Expo, Seth Proctor, CTO at NuoDB, Inc., will discuss the experiences from building, deploying and using enterprise services and suggest some ways to approach moving enterprise applications into a cloud model.
Until recently, many organizations required specialized departments to perform mapping and geospatial analysis, and they used Esri on-premise solutions for that work. In his session at 15th Cloud Expo, Dave Peters, author of the Esri Press book Building a GIS, System Architecture Design Strategies for Managers, will discuss how Esri has successfully included the cloud as a fully integrated SaaS expansion of the ArcGIS mapping platform. Organizations that have incorporated Esri cloud-based applications and content within their business models are reaping huge benefits by directly leveraging cloud-based mapping and analysis capabilities within their existing enterprise investments. The ArcGIS mapping platform includes cloud-based content management and information resources to more widely, efficiently, and affordably deliver real-time actionable information and analysis capabilities to your organization.
Almost everyone sees the potential of Internet of Things but how can businesses truly unlock that potential. The key will be in the ability to discover business insight in the midst of an ocean of Big Data generated from billions of embedded devices via Systems of Discover. Businesses will also need to ensure that they can sustain that insight by leveraging the cloud for global reach, scale and elasticity. In his session at Internet of @ThingsExpo, Mac Devine, Distinguished Engineer at IBM, will discuss bringing these three elements together via Systems of Discover.
Cloud and Big Data present unique dilemmas: embracing the benefits of these new technologies while maintaining the security of your organization’s assets. When an outside party owns, controls and manages your infrastructure and computational resources, how can you be assured that sensitive data remains private and secure? How do you best protect data in mixed use cloud and big data infrastructure sets? Can you still satisfy the full range of reporting, compliance and regulatory requirements? In his session at 15th Cloud Expo, Derek Tumulak, Vice President of Product Management at Vormetric, will discuss how to address data security in cloud and Big Data environments so that your organization isn’t next week’s data breach headline.
The cloud is everywhere and growing, and with it SaaS has become an accepted means for software delivery. SaaS is more than just a technology, it is a thriving business model estimated to be worth around $53 billion dollars by 2015, according to IDC. The question is – how do you build and scale a profitable SaaS business model? In his session at 15th Cloud Expo, Jason Cumberland, Vice President, SaaS Solutions at Dimension Data, will give the audience an understanding of common mistakes businesses make when transitioning to SaaS; how to avoid them; and how to build a profitable and scalable SaaS business.
SYS-CON Events announced today that Gridstore™, the leader in software-defined storage (SDS) purpose-built for Windows Servers and Hyper-V, will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Gridstore™ is the leader in software-defined storage purpose built for virtualization that is designed to accelerate applications in virtualized environments. Using its patented Server-Side Virtual Controller™ Technology (SVCT) to eliminate the I/O blender effect and accelerate applications Gridstore delivers vmOptimized™ Storage that self-optimizes to each application or VM across both virtual and physical environments. Leveraging a grid architecture, Gridstore delivers the first end-to-end storage QoS to ensure the most important App or VM performance is never compromised. The storage grid, that uses Gridstore’s performance optimized nodes or capacity optimized nodes, starts with as few a...
SYS-CON Events announced today that Solgenia, the global market leader in Cloud Collaboration and Cloud Infrastructure software solutions, will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Solgenia is the global market leader in Cloud Collaboration and Cloud Infrastructure software solutions. Designed to “Bridge the Gap” between personal and professional social, mobile and cloud user experiences, our solutions help large and medium-sized organizations dramatically improve productivity, reduce collaboration costs, and increase the overall enterprise value by bringing collaboration and infrastructure solutions to the cloud.
Cloud computing started a technology revolution; now DevOps is driving that revolution forward. By enabling new approaches to service delivery, cloud and DevOps together are delivering even greater speed, agility, and efficiency. No wonder leading innovators are adopting DevOps and cloud together! In his session at DevOps Summit, Andi Mann, Vice President of Strategic Solutions at CA Technologies, will explore the synergies in these two approaches, with practical tips, techniques, research data, war stories, case studies, and recommendations.
Enterprises require the performance, agility and on-demand access of the public cloud, and the management, security and compatibility of the private cloud. The solution? In his session at 15th Cloud Expo, Simone Brunozzi, VP and Chief Technologist(global role) for VMware, will explore how to unlock the power of the hybrid cloud and the steps to get there. He'll discuss the challenges that conventional approaches to both public and private cloud computing, and outline the tough decisions that must be made to accelerate the journey to the hybrid cloud. As part of the transition, an Infrastructure-as-a-Service model will enable enterprise IT to build services beyond their data center while owning what gets moved, when to move it, and for how long. IT can then move forward on what matters most to the organization that it supports – availability, agility and efficiency.