The container runtime is a basic building block. If it moves too fast (and in broken ways), stuff on top of it breaks. If Intel processors came with a completely new instruction set in every generation, it'd be hell.

I don't think people are suggesting that Docker Inc. should be boring. The criticism is more targeted towards Docker Engine, the container runtime.

Personally I think the entire container space moves too quickly to be a good target for stable long lived services. Pretty much every element is under fast development.

Stability is more the attribute of more mature services like Virtual machines, which have been around as a heavily used technology for quite a long time now...

The funny part about this is CoreOS is talked about being one of the players in the article, and they are the developers of rkt.

From the article:

> Spokespeople from ... CoreOS denied any knowledge of Docker-related talks.

Indeed, I did think that was rather odd...

IMO, they shouldn't get behind rkt, because it too is owned and primarily developed by a company who uses it as a commodity to sell their own products as well, and the same concerns arising from Docker wholly owning development against Docker Engine could very easily arise against rkt as well.

I believe an independent project managed by a board of shareholders would be better for us all.

We (CoreOS) built rkt because we feel strongly that the container engine should be a stable and fundamental building block of software. By itself rkt is not a product and we want to ensure it is something that can be integrated into other systems. For example, we continue to add rkt support to Kubernetes[1] to provide a user transparent option for container engines. Similarly, there are integrations with Mesos and others.

Also, rkt has had significant external contribution like the virtual machine isolation work from Intel[2]. We have spun out independent projects like the Container Networking Interface (CNI)[3] that is now used in Kubernetes, Cloud Foundry, and Mesos.

Stable and robust components are necessary to make this ecosystem work for people operating them. And we built rkt to help the entire ecosystem (and yes ourselves) be successful with that. The product strategy ends there. If a community of folks felt putting rkt into an independently managed foundation would help achieve that goal we would be happy to do that work with others.

But, I think the project has a good track record of working with others and focusing on a narrow feature set.

[1] http://blog.kubernetes.io/2016/07/rktnetes-brings-rkt-contai... [2] https://coreos.com/blog/rkt-0.8-with-new-vm-support/ [3] https://github.com/containernetworking/cni

Out of curiousity, where do you feel that Docker has less of a focus on stability than rkt, is it just in releasing swarm or in other areas?

Whilst I'm more familiar with Docker than rkt it seems that both projects are still changing quite quickly and have a lot of movement in terms of features being added & changed...

rkt tries to stay out of the way for everything that isn't "download, validate, and execute a container". For example, it doesn't know about networks but will hook out to CNI to setup a network namespace. It isn't an init system and will instead rely on a system init system to monitor it. It doesn't do any clustering but can be used by things like Kubernetes.

I'd agree that if it seems that containerization is a fundamental part of an OS that it would make sense to have a neutral platform for it.

That said there were containerization efforts in this area in the past (e.g. LXC) which never really seemed to attract the same kind of traction as Docker.

Ultimtely if people want to create containers, it's entirely possible to do with pure linux commands and no upper-level software at all, it's just Docker makes it much easier/nicer to achieve :)

> Ultimately, if people wanted to create [text files], it's entirely possible to do with pure linux commands with no upper level software at all, it's just [Sublime Text] makes it much easier/nicer to achieve.

It's absolutely possible (see: Bocker), but not a very productive way to go about things. It's much more productive to take an existing technology and make it better than to start from scratch (yet again), especially with permissive licenses like those used in Docker Engine.

possibly although unless they got a decent number of the original developers across in a fork (Which seems somewhat unlikely) it would be a pretty difficult thing to pull off to maintain/develop the codebase.

Not sure I can think of a case where a fork has been successful without a decent percentage of the original developers supporting it.

I think that LXC was on a good path if you were an Ubuntu shop, however I think that tying LXD to Openstack was an odd choice.

How is LXD tied to openstack? You can use LXD in exactly the same way you used LXC (with a nicer CLI interface, no less).

nova-lxd adds lxd as a "hypervisor" choice for openstack, but it's a completely optional way to use it.

Try it on ubuntu right now: sudo apt-get install lxd; lxc list (yes, the client for lxd is called lxc, it's kind of confusing. Sorry.)

Disclaimer: I work for Canonical, but not on LXD (I use it daily outside of openstack though)

I don't think rkt is a valid candidate. People are already used to the basic of Docker command. There is no reason to change to something else. If rkt decides to reproduce the feature set, how is that different from a fork?

People being used to the Docker commands is a very weak reason rkt isn't a valid candidate. Let's not forget the most important aspect of rkt, and that is that it follows the container spec standard.

> People are already used to the basic of Docker command.

The tiny amount of existing early adopters can be made to adopt something else one more time.

Not to mention that they constantly break the Docker api and interactions. Knowing the commands today is not helpful in the future. Once you get past "docker run <image>" so much has changed the last couple of years that it is pointless to hold that up as a virtue.

So the challenge, to me, is that if you fork docker, then people are going to have to get used to a different command structure anyway as the forks will diverge.

One of the reasons to avoid a fork is the confusion caused by two kind of similar but not quite the same implementations that diverge slowly over time.

rkt is unlikely to just copy the feature set of Docker, but they provide competition in implementing new ideas and as it's not intended to be identical there's less confusion.