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How is Docker.io different from a normal virtual machine?

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Re: How is Docker.io different from a normal virtual machine?

#91

Post by pekk »

jaytaylor wrote: post #26
seldo wrote: post #23

Earlier quoted context omitted.

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…

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.

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?

Re: How is Docker.io different from a normal virtual machine?

#92

Post by pekk »

jaytaylor wrote: post #35
jaytaylor wrote: post #26

Earlier quoted context omitted.

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.

Anything not pro-docker usually gets downvoted by shykes and his ring of cronies.

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.

Re: How is Docker.io different from a normal virtual machine?

#93

Post by wmf »

shykes wrote: post #31
est wrote: post #29

I always wanted to ask a question about docker, if the local devel machine is ubuntu 12.04, I can not deploy my docker image build to a 10.04 ubuntu server, right? (Unless you run a 12.04 virtual machine or something.)

Yes you can. Docker doesn't care about the underlying distro, as long as it can run on it. You can build a container on a Red Hat host machine, and transfer it to an Ubuntu host machine - it will run just fine on both.

But Docker can't run on 10.04, right?

Re: How is Docker.io different from a normal virtual machine?

#94

Post by pekk »

darklajid wrote: post #66
seldo wrote: post #23

Earlier quoted context omitted.

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…

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 he…

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.

Re: How is Docker.io different from a normal virtual machine?

#95

Post by kordless »

microtonal wrote: post #61
FreeBSD-user wrote: post #46

Earlier quoted context omitted.

To be honest I've never worked out why Docker gets so much press. If you use the Ezjail utility to configure and manage FreeBSD jails you have been able to do most of the things Docker does for years (stacked fs using unionfs, templates/flavours, snapshots, export/import etc) and this seems like a much simpler and more stable solution. The networking stuff is also easy using pf.

There's also Solaris Containers, which leverages ZFS snapshots, etc.: http://en.wikipedia.org/wiki/Solaris_Containers Of course, Solaris is even more despised by some people since they changed hands. I think Docker appeals more to people, because: - It's on Linux, which is more popular than FreeBSD or Solaris. - It's very easy to set up and configure. - Integration with Puppet et al. - The have great marketing :).

All hail the whale.

Re: How is Docker.io different from a normal virtual machine?

#96

Post by shykes »

pekk wrote: post #94
darklajid wrote: post #66

Earlier quoted context omitted.

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 he…

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.

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.

Re: How is Docker.io different from a normal virtual machine?

#97

Post by jessaustin »

wmf wrote: post #93
shykes wrote: post #31

Earlier quoted context omitted.

Yes you can. Docker doesn't care about the underlying distro, as long as it can run on it. You can build a container on a Red Hat host machine, and transfer it to an Ubuntu host machine - it will run just fine on both.

But Docker can't run on 10.04, right?

It depends on the kernel version rather than the distro version. So if the 3.8 kernel is compatible with the 10.04 distro, you'd be fine.

Sorry I don't actually know if that kernel is compatible with such an old distro. I sort of doubt many people would have been interested enough to do the backport...

Re: How is Docker.io different from a normal virtual machine?

#98

Post by passfree »

mtam wrote: post #54
bobf wrote: post #7

Docker doesn't add a whole lot over what basic Linux containers (lxc and vserver) have offered for years. Having said that, the main benefit to Docker is a change in viewpoint from "virtual machine" to "application". Docker aims to make applications portably deployable to any Docker-machine. Since Docker uses lxc (aka Linux containers), it helps to understand a little how containers are different from other virtualiz…

Yes, Docker builds on top Linux containers but they seem to be releasing some neat features that make containers easier to use, manage, and reuse. For example: The docker-cluster project, https://github.com/globocom/docker-cluster seems very interesting as it might allow you to abstract the host with a cluster/logical group. Having this abstraction is key if you are running docker on a non-virtualized (bare metal) ho…

You can also have a look at VxDocker https://github.com/websecurify/node-vxdocker

Re: How is Docker.io different from a normal virtual machine?

#100

Post by jaytaylor »

jaytaylor wrote: post #35
jaytaylor wrote: post #26

Earlier quoted context omitted.

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.

Anything not pro-docker usually gets downvoted by shykes and his ring of cronies.

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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