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A comment on How is Docker.io different from a normal virtual machine?. Parent comment

Re:How is Docker.io different from a normal virtual machine? by seiji on Friday September 13, 2013 @12:30AM (#6378640)
Containers are not virtual.

Containers aren't emulating anything or translating anything. They let your partition out system and network resources as you see fit (or to protect users from abusing each other) without running kernels within kernels and other performance killing hokum.

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Re:How is Docker.io different from a normal virtual machine? by seldo on Friday September 13, 2013 @01:18AM (#6378803)
Indeed. One way you can use Docker in production[1] is one container per machine: even when you're not using the containers to split resources, the ability to snapshot and move an application and all of its dependencies in a single, lightweight, easily deployed package is very exciting. And because there's no translation etc. happening, running a single container is pretty much identical, performance-wise, to running it directly on the machine[2].

[1] dotCloud don't actually yet recommend running Docker in production, but if you did...

[2] This was part of what Mailgun (part of Rackspace) said in their presentation at the Docker workshop in SF today.

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Re:How is Docker.io different from a normal virtual machine? by jaytaylor on Friday September 13, 2013 @01:28AM (#6378827)
You can actually do the same thing with LXC containers; it is trivial to rsync a snapshot or compressed archive of a snapshot to another host machine and run it there.
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Re:How is Docker.io different from a normal virtual machine? by pestaa on Friday September 13, 2013 @01:55AM (#6378893)
Why the downvote? Simple tools always work well. If you want process isolation on Linux, LXC + rsync might as well be the simplest route.
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Re:How is Docker.io different from a normal virtual machine? by mritun on Friday September 13, 2013 @02:14AM (#6378950)
Docker is based on LXC containers. It bundles it's own management layer that replaces the "rsync" solution you propose.
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Re:How is Docker.io different from a normal virtual machine? by pekk on Friday September 13, 2013 @12:01PM (#6381309)
The point of Docker is the standardized container/management interface. Of course you can write your own, but then it's not too standardized is it?
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Re:How is Docker.io different from a normal virtual machine? by jaytaylor on Friday September 13, 2013 @05:52PM (#6383418)
What you describe is standardizing complexity where a simple solution is available. Naturally, when feasible, I prefer keeping things simple and straightforward enough that standardization is unnecessary.

Standardization for the sake of standardization is not defensible.

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Re:How is Docker.io different from a normal virtual machine? by jaytaylor on Friday September 13, 2013 @01:58AM (#6378904)
Anything not pro-docker usually gets downvoted by shykes and his ring of cronies.
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Re:How is Docker.io different from a normal virtual machine? by aegiso on Friday September 13, 2013 @02:22AM (#6378979)
There's definitely hype behind Docker, but this is a ridiculous accusation.
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Re:How is Docker.io different from a normal virtual machine? by jaytaylor on Friday September 13, 2013 @02:55AM (#6379057)
People do crazy things for money.
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Re:How is Docker.io different from a normal virtual machine? by pekk on Friday September 13, 2013 @12:06PM (#6381331)
You have rationalized away the people who disagree with you by making them into a conspiracy. I don't know about said ring of cronies, but I guarantee that many downvoters are not associated.
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Re:How is Docker.io different from a normal virtual machine? by jaytaylor on Friday September 13, 2013 @05:41PM (#6383364)
My claim seems validated. Just look at both of my comments in this thread; they've both been downvoted deep into the negatives.
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Re:How is Docker.io different from a normal virtual machine? by kbutler on Friday September 13, 2013 @06:36PM (#6383620)
My downvotes because the comments were disparaging and lacked proof. My only Docker affiliation is reading a bit about it lately. I had to search the page to see who shykes is.
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Re:How is Docker.io different from a normal virtual machine? by darklajid on Friday September 13, 2013 @05:23AM (#6379383)
Regarding your first footnote:

Is there an explanation why 'in production' is actively discouraged? Is that a limitation of the underlying lxc stuff?

I ask, because the interesting parts of docker _for me_ seem to be focused on the setup, deployment - and not the runtime. So if I create a working image and want to use that in production, wouldn't docker become passive as soon as I run that thing?

What's the danger here?

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Re:How is Docker.io different from a normal virtual machine? by pekk on Friday September 13, 2013 @12:08PM (#6381348)
I expect the danger is that someone will lose money and blame the developers for as-yet unforeseen issues which can only be smoked out after a few years of heavy use. But a specific danger would be interesting to hear.
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Re:How is Docker.io different from a normal virtual machine? by shykes on Friday September 13, 2013 @02:12PM (#6382085)
Docker maintainer here. That's basically it. There's no specific danger that we're worried about - just engineering best practices.

As long as we're not comfortable operating Docker at large scale ourselves (we run quite a lot of containers in production at dotCloud), we won't recommend that others do it.

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Re:How is Docker.io different from a normal virtual machine? by contingencies on Friday September 13, 2013 @05:30AM (#6379396)
Containers are not virtual.

They belong to a category of virtualization known as 'container-based virtualization' which implements virtualized perspectives of the system within the host kernel, effectively dividing the system in to multiple systems (from the perspective of the affected processes). That is unquestionably virtualization.

I believe a statement closer to what you were looking to express was containers are not running under a hypervisor.

LXC still creates a performance impact, depending upon which options are selected, with particular note for the various memory accounting options. However, that impact is far lower than a hypervisor. In addition, startup times are vastly reduced since the kernel bootstrap and hardware detection concerns are rendered unnecessary.

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Re:How is Docker.io different from a normal virtual machine? by lrem on Friday September 13, 2013 @08:32AM (#6380004)
I don't know about LXC, but back in the day, the impact of linux-vserver was within bounds of measurement error. Since then I have been using it reflexively on any server I touch, even if it ends with only one container.
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