Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Docker interactive tutorial

blog.docker.io

Post reply on HN
Print view View original

21–30 of 48 posts

Re: Docker interactive tutorial

#21

Post by jtreminio »

tootie wrote: post #16
csears wrote: post #14

Earlier quoted context omitted.

Regarding who is supposed to use it... If you like deploying your apps to a Platform-as-a-Service (PaaS) like Heroku, Google AppEngine, or DotCloud, but wanted to run it on your own infrastructure, then Docker could be for you! It's designed to be a key building block for anyone who wants to create their own PaaS-like service or environment. Why would you need your own PaaS? You might have unique security requirement…

So I'm used to configuring stuff by hand, and now I see a lot of buzz around docker, vagrant, chef, puppet, salt and they seem like glorified shell scripts. Am I missing something?

Vagrant is a little bit different - it takes the process of booting up a new VM instance (think VirtualBox/VMWare) and automates much of the process of:

1. Choosing OS / flavor / architecture (Debian 7 x64),

2. Setting up networking (private network with its own IP address),

3. Setting up SSH access ($ vagrant ssh),

4. Kicking off provisioning (Chef/Puppet/Salt/Ansible/Bash)

With Vagrant, if you're playing around in your VM and accidently screw something up and can't recover [0], you simply "$ vagrant destroy" and "$ vagrant up" and you'll have a working VM again.

Couple Vagrant with Puppet, and if you destroy/up you'll have your VM go through the process of installing all software and settings and everything for you, meaning your full, working environment is back up and running within minutes, just as it was before you screwed it up.

[0] I experienced this several times when my apt-get stuff would screw up and I couldn't install/remove/purge anything. Google and #debian never let me recover.

Re: Docker interactive tutorial

#22

Post by shykes »

tootie wrote: post #16
csears wrote: post #14

Earlier quoted context omitted.

Regarding who is supposed to use it... If you like deploying your apps to a Platform-as-a-Service (PaaS) like Heroku, Google AppEngine, or DotCloud, but wanted to run it on your own infrastructure, then Docker could be for you! It's designed to be a key building block for anyone who wants to create their own PaaS-like service or environment. Why would you need your own PaaS? You might have unique security requirement…

So I'm used to configuring stuff by hand, and now I see a lot of buzz around docker, vagrant, chef, puppet, salt and they seem like glorified shell scripts. Am I missing something?

The big difference with just scripts is that you can "freeze" the state of your deployment with strong guarantees that 1) it will not change and 2) it will behave the same way across machines.

Another advantage of containers is that deployment can be made atomic: either container A is running, or container B. You can't end up with a half-finished upgrade which leaves your server in an undefined, broken state. That property becomes very important when you deploy to a large number of servers.

Re: Docker interactive tutorial

#23

Post by shykes »

jpetazzo wrote: post #6
zhemao wrote: post #3

Haha, I had a good laugh upon hearing that Docker cannot run inside of itself. Is this an LXC limitation? Clearly the solution was to run Docker inside of KVM inside of Docker. But seriously, nice job. I haven't used docker yet because I want to play around with the standard lxc utilities first. But this is pretty awesome.

Actually, I've ran Docker within QEMU within Docker (using v9fs so that QEMU could use the container's FS as root FS). Works, but painfully slow and not very resource-efficient :-)

I will add that Docker is getting an architecture upgrade, and in the future will support nesting :)

Re: Docker interactive tutorial

#24

Post by buster »

dhrp wrote: post #17
simonebrunozzi wrote: post #11

Earlier quoted context omitted.

Hi dhrp, I assume you work for Dotcloud? Nice job so far. Where do you see this heading to? What's your view of what will happen in the virtualization world? Best,

Hi. Thanks! My personal take on where Docker is heading to? There are so many things people can do with this, it's hard to summarize. What I personally care most about? As a designer ex-entrepreneur and front-end developer, the thing that gets me going most is the idea that I'm able to "just run" an application. No more difficult than from the Mac store. For example Trac (a wiki system), Wordpress, Django apps, Mails…

Absolutely love docker, hope to see it mature even more :)

I am currently playing around with it and building a messaging platform playground. One "pain" so far is that docker's IPAddress assignment is not very flexible. Will it be possible to assign IP addresses to containers (e.g. from "docker run")? Or have a better control what IPAddresses are used (like giving a network range on docker -d)?

If i am not mistaken docker saves changes in containers through aufs and keeps those changes as separate images on disk, right? I'm currently working with containers which keep their state on the host OS (by mount bindings) and thus, i don't want to keep old images of not-running containers. Will there be some switch to disable that or clean up old ones? Maybe i am misinterpreting something, but i'm new to docker ;)

Anyway, keep up the great work, i am very impressed with docker, kudos!!

Re: Docker interactive tutorial

#26

Post by zhemao »

jpetazzo wrote: post #6
zhemao wrote: post #3

Haha, I had a good laugh upon hearing that Docker cannot run inside of itself. Is this an LXC limitation? Clearly the solution was to run Docker inside of KVM inside of Docker. But seriously, nice job. I haven't used docker yet because I want to play around with the standard lxc utilities first. But this is pretty awesome.

Actually, I've ran Docker within QEMU within Docker (using v9fs so that QEMU could use the container's FS as root FS). Works, but painfully slow and not very resource-efficient :-)

Yeah, I was kidding about Docker in KVM in Docker. I know it would be a lot of overhead.

Re: Docker interactive tutorial

#27

Post by shykes »

seiji wrote: post #25

Why is the docker hype machine cranked up to 11?

Hi seiji, I'm the author of Docker.

There is hype around docker, for sure. The optimist in me likes to think that it's because people find the project useful and are excited about the possibilities of containers in general - which I believe are huge.

Me and the dotCloud team have been working on container technology since 2008. For a long time it felt like preaching in the desert - mostly because it required exotic patches to the kernel which made widespread adoption difficult. So it's very rewarding to see more people adopt containers, and of course it's great to be on the right side of the hype for a change. But if we hadn't been at the right place at the right time, someone else would have done it instead. Containers are just too important and useful to not blow up.

Re: Docker interactive tutorial

#28

Post by dhrp »

agumonkey wrote: post #5

Enjoyed it, more would be welcome, only if you have more time to give of course. ps: especially on committing and layering.

Yeah. The committing and layering stuff is not the easiest to grasp. There is actually a section on the docs that does a decent job explaining these concepts but it is a bit hidden: http://docs.docker.io/en/latest/terms/

Re: Docker interactive tutorial

#29

Post by ams6110 »

zhemao wrote: post #3

Haha, I had a good laugh upon hearing that Docker cannot run inside of itself. Is this an LXC limitation? Clearly the solution was to run Docker inside of KVM inside of Docker. But seriously, nice job. I haven't used docker yet because I want to play around with the standard lxc utilities first. But this is pretty awesome.

Would there be a useful reason to actually do this (run Docker in Docker), or is it more just a novelty?

Re: Docker interactive tutorial

#30

Post by shykes »

ams6110 wrote: post #29
zhemao wrote: post #3

Haha, I had a good laugh upon hearing that Docker cannot run inside of itself. Is this an LXC limitation? Clearly the solution was to run Docker inside of KVM inside of Docker. But seriously, nice job. I haven't used docker yet because I want to play around with the standard lxc utilities first. But this is pretty awesome.

Would there be a useful reason to actually do this (run Docker in Docker), or is it more just a novelty?

If anything, it's needed for the development of docker itself. We already build docker with docker (https://github.com/dotcloud/docker/blob/master/Dockerfile), but we can't yet test docker with docker because of the nesting problem.
Post reply on HN