At DockerCon 2015, Solomon Hykes announced that a broad coalition of vendors, users and industry leaders are coming together to form the Open Container Project (OCP) for the express purpose of defining common specifications around container format and runtime. The OCP will be run under the auspices of the Linux Foundation as a minimalist, non-profit, openly governed project.
Hykes, founder and CTO at Docker Inc., stated that Docker will be donating both the current base container format and runtime, now named runC, to the Open Container Project (OCP) in order to help form the cornerstone for the new technology. Hykes also announced that the team behind the CoreOS-driven Application Container (appc) specification are joining as co-founders of the OCP. Hykes acknowledged the work of the CoreOS team:
I am especially grateful that Alex Polvi and Brandon Phillips from CoreOS, the founders of appc, will be joining the OCP, as it speaks volumes about our common desire to help unite the industry and to take the best ideas, wherever they originated, into something that provides the best outcomes for users and the industry
The CoreOS blog states that it is expected that concepts behind the community-driven appc specification and the current ‘de facto’ Docker image specification will converge to form a new specification:
We believe most of the core concepts from App Container will form an important part of OCP. Our experience developing App Container will play a critical role as we begin collaboration on the OCP specification.
[...]
The end goal is to converge on a single unified specification of a standard container format, and the success of OCP will mean the major goals of App Container are satisfied.
Additional founding members of the OCP include more than twenty organisation, which Hykes suggested represent a ‘significant share of the container market’. Hykes mentioned the following founding members in his DockerCon keynote: Apcera, AWS, Cisco, CoreOS, Docker, EMC, Fujitsu Limited, Google, Goldman Sachs, HP, Huawei, IBM, Intel, Joyent, Pivotal, the Linux Foundation, Mesosphere, Microsoft, Rancher Labs, Red Hat, and VMware.
The Docker blog post that announced the formation of the OCP states that although Docker has changed a lot since launching in March of 2013, a few key principles have always held:
- Design based on Unix principles for composability and simplicity
- Emphasize the ecosystem
- Do what’s best for the user
The Docker blog argues that the creation of the OCP and donation of runC serves all of these goals. Firstly, there is a desire to creation simple, clear, modular, and extensible code that can be easily maintained and repurposed by developers other than its creators.
[...] by explicitly separating “the box” from the tools that build, ship, and run those boxes, we think we fundamental help preserve those values of composability and simplicity. [...] A simple runtime that is well specified that can call and manipulate a well documented, standard format speaks to this view
Second, this effort will allow the emerging container ecosystem to focus on innovation on the areas that add value, rather than wasting time fighting a low level ‘standards war’.
This is especially important at time when Docker and containers in general are expanding beyond 64 bit Linux to multiple architectures and operating systems, including 32 bit, Power, Z, Windows and SmartOS.
Third, Hykes stated that ‘this is the right thing for users’, and that users will be able to commit to Docker, CoreOS or any other vendor that creates products that are compliant of the OCP specifications without worrying about lock-in with their current choice of any particular infrastructure, vendor or tooling.
Instead, [a user’s] choices can be guided by choosing the best damn tools to build the best damn applications they can.
The Docker blog states that the entire contents of the libcontainer project, including nsinit, and all modifications needed to make it run independently of Docker have been donated to this effort. This codebase, runC, can be found at the OCP Github repository. Libcontainer will cease to operate as a separate project.
Details of the OCP initiative can be found at www.opencontainers.org. This includes both reference code and draft specifications, and also details on the proposed governance structure. More information on DockerCon, and the ability to watch the live-streamed general conference sessions, can be found on the DockerCon 2015 website.