With the ratification of an Open Container Initiative 1.0 (OCI) specification announced today by The Linux Foundation, IT organizations now should have greater confidence in the fact that container images will be portable across multiple classes of container engines.
The OCI project came about as result of a drive by CoreOS to set create a rkt alternative to the Docker container format created by Docker Inc. Under the auspices of The Linux Foundation, it was then proposed that a specification be created to ensure the container engine playing field remains level by combining container image and runtime code contributed mainly by CoreOS and Docker Inc.
IT organizations now can mix and match container engines as they see fit and be assured that whatever container images they generate today will be able to run on any platform that support the OCI specification.
CoreOS CTO Brandon Philips says the ratification of specification is indicative of a container market that is rapidly maturing and will continue to grow for years to come. Not only can container images that comply with the specification be deployed on Linux servers, but they also will be deployable on Windows Server, various types of virtual machines and even mainframes. IT organizations will also be able to port those images between container-as-a-service (CaaS) environments and platform-as-a-service (PaaS) environments.
Most of those platforms will also have to be upgraded to meet the specifications. The Kubernetes container orchestration engine, for example, already employs some elements of OCI specification today, but will be adding further support for the OCI Image and OCI Runtime specifications in future releases. Similarly, tools used for creating container images would also need to be updated as well.
David Messina, senior vice president of marketing for Docker Inc. says the major significance of OCI for IT organizations is that it guarantees a level of future-proofing regardless of how underlying IT infrastructure architectures evolve over time. At the same time, he cautions IT organizations that even though there is now a formal certification, each vendor seeking to comply with the OCI specification will need to be certified. The tools and processes surrounding that certification process won’t be completed until later this year, he says.
Messina also notes that the OCI specification is far from complete. The initial scope was to define a narrow specification for the runtime behavior of a container as it applies to a container image. Future projects that might be addressed via an OCI working group include distribution and signing, he says.
It remains to be seen how many IT organizations will require OCI compliance as a prerequisite for deploying containers in a production environment. The specification has the backing of industry stalwarts including IBM, Red Hat, Microsoft and Google, all of whom for their own reasons will be anxious to promote adoption of an OCI specification to prevent customers from becoming locked into a proprietary platform. What remains to be seen now is just how broadly the rest of the IT industry will get behind that specification.