Docker went quickly from obscurity to ubiquity. A couple years ago the company didn’t exist and now it’s established as the de facto standard for container technologies—integrated in almost every platform and supported by most major vendors. Somewhere in that meteoric rise, though, it seems like Docker veered off its original course.
When it began Docker also created the Standard Container Manifesto:
Docker: a self-sufficient runtime for linux containers
Docker is a runtime for Standard Containers. More specifically, it is a daemon which automates the creation of and deployment of linux Standard Containers (SCs) via a remote API.
Standard Containers are a fundamental unit of software delivery, in much the same way that shipping containers (http://bricks.argz.com/ins/7823-1/12) are a fundamental unit of physical delivery.
1. STANDARD OPERATIONS
Just like shipping containers, Standard Containers define a set of STANDARD OPERATIONS. Shipping containers can be lifted, stacked, locked, loaded, unloaded and labelled. Similarly, standard containers can be started, stopped, copied, snapshotted, downloaded, uploaded and tagged.
Just like shipping containers, Standard Containers are CONTENT-AGNOSTIC: all standard operations have the same effect regardless of the contents. A shipping container will be stacked in exactly the same way whether it contains Vietnamese powder coffe or spare Maserati parts. Similarly, Standard Containers are started or uploaded in the same way whether they contain a postgres database, a php application with its dependencies and application server, or Java build artifacts.
Both types of containers are INFRASTRUCTURE-AGNOSTIC: they can be transported to thousands of facilities around the world, and manipulated by a wide variety of equipment. A shipping container can be packed in a factory in Ukraine, transported by truck to the nearest routing center, stacked onto a train, loaded into a German boat by an Australian-built crane, stored in a warehouse at a US facility, etc. Similarly, a standard container can be bundled on my laptop, uploaded to S3, downloaded, run and snapshotted by a build server at Equinix in Virginia, uploaded to 10 staging servers in a home-made Openstack cluster, then sent to 30 production instances across 3 EC2 regions.
4. DESIGNED FOR AUTOMATION
Because they offer the same standard operations regardless of content and infrastructure, Standard Containers, just like their physical counterpart, are extremely well-suited for automation. In fact, you could say automation is their secret weapon.
Many things that once required time-consuming and error-prone human effort can now be programmed. Before shipping containers, a bag of powder coffee was hauled, dragged, dropped, rolled and stacked by 10 different people in 10 different locations by the time it reached its destination. 1 out of 50 disappeared. 1 out of 20 was damaged. The process was slow, inefficient and cost a fortune – and was entirely different depending on the facility and the type of goods.
Similarly, before Standard Containers, by the time a software component ran in production, it had been individually built, configured, bundled, documented, patched, vendored, templated, tweaked and instrumented by 10 different people on 10 different computers. Builds failed, libraries conflicted, mirrors crashed, post-it notes were lost, logs were misplaced, cluster updates were half-broken. The process was slow, inefficient and cost a fortune – and was entirely different depending on the language and infrastructure provider.
5. INDUSTRIAL-GRADE DELIVERY
There are 17 million shipping containers in existence, packed with every physical good imaginable. Every single one of them can be loaded on the same boats, by the same cranes, in the same facilities, and sent anywhere in the World with incredible efficiency. It is embarrassing to think that a 30 ton shipment of coffee can safely travel half-way across the World in *less time* than it takes a software team to deliver its code from one datacenter to another sitting 10 miles away.
With Standard Containers we can put an end to that embarrassment, by making INDUSTRIAL-GRADE DELIVERY of software a reality.
The core principles of the Standard Container Manifesto make sense. Organizations can embrace container technologies with greater confidence if there is a standard in place that doesn’t paint them into a proprietary corner. Vendors and platforms can support containers easier if they can support a standard rather than having to choose sides and pick winner and losers in the container market. The idea of a standard container is part of what drove Docker’s popularity in the first place.
As demand and support for Docker exploded, though, it seems like the company shifted its focus. CoreOS—a former ally-turned-competitor—noted that Docker removed the Standard Container Manifesto as it branched out to build tools for launching cloud servers, and systems for clustering containers, and a variety of other features and functions including building and running images. The net result is a gigantic binary running more or less as root on the server and providing an entire framework of capabilities. The simple Docker container quickly turned into an unwieldy Docker platform.
Whatever Docker has become, though, it has left a void where it originally started—the need to create and maintain the concept of a standard container. CoreOS took on the challenge of picking up where Docker left off. CoreOS developed its own container technology and container runtime to not only build on the basic container concept but also to improve on some areas it felt were fundamentally flawed with the Docker design.
I’m not judging. Companies adapt and evolve. Strategies change. It may have been foolish of Docker not to capitalize on its notoriety to expand its vision. The shift in focus certainly hasn’t seemed to have any impact on the popularity of Docker.