Docker

Transcript

1. Anil Wadghule
   awadghule@equalexperts.com
   February 2014 — Docker 0.8.0
   

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2. Docker
   • Docker was started by Solomon Hykes as an internal project by
   dotCloud
   • Docker makes Linux Containers easy to use
   

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3. What is Docker?
   “Docker is an open source engine to easily create lightweight,
   portable, self-sufficient containers from any application. The same
   container that a developer builds and tests on a laptop can run at
   scale, in production, on VMs, bare metal, OpenStack clusters, public
   clouds and more” - http://docker.io
   

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4. Why Docker?
   • Deploy everything (webapps, backends, sql, big data, message
   queues)
   • Deploy almost everywhere (Linux servers, VMs or bare metal, any
   distro, Kernel 3.8)
   • Deploy reliably & consistently (local and on server same)
   • Deploy easily
   • Deploy at scale
   

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5. Docker popularity
   • 330+ Contributors,
   • 50,000+ docker index pull,
   • 1000’s of Dockerized applications
   • Integration in Jenkins, Travis, Chef, Puppet, Vagrant & OpenStack
   

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6. The challenge
   • Static website, User DB, Queue, Background workers, Analytics DB,
   API endpoint, Web Frontend
   • Development VM, QA Server, Public cloud, Production Servers,
   Customer data center, Production cluster
   • Running apps in multiple environments results in N x N nightmare
   

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7. N x N compatibility nightmare
   Problem: shipping code
   

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8. Solution
   • The Linux Container
   

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9. This eliminated the N x N problem
   

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10. What is LXC?
    • Lightweight Linux Container (LXC)
    • Operating system level virtualisation method for running multiple
    isolated Linux systems
    • Provides way to run mini Linux systems within another Linux systems
    • http://en.wikipedia.org/wiki/LXC
    

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11. LXC
    • I can SSH into it
    • I have root access
    • I can apt-get/yum install packages
    • Speed: boots in seconds
    • Footprint: 100-1000 containers on one machine. Small disk
    requirements.
    

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12. Control groups & namespaces
    • LXCs makes use of control groups & namespaces
    • Linux kernel feature to limit, account and isolate resource usage,
    such as 

    — CPU 

    — Memory 

    — Disk I/O
    

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13. Docker
    • Docker is API on top of LXC
    • Docker runs as daemon
    • Docker makes Linux Containers easy to use (LXC)
    • Docker service exposes REST api that is used by Docker client
    

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14. Docker architecture
    DOCKER
    LAYER FS
    LXC
    CGROUPS
    LINUX KERNEL
    NAMESPACES
    

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15. Container vs. VMs
    

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16. Docker operating system?
    • Doesn’t include operating system
    • Relies on operating system functionality provided by underlying
    infrastructure
    

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17. Requirements
    • Linux kernel 3.8 & above
    • AUFS
    • LXC
    • 64-bit
    

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18. Installation
    • Can be directly installed on supported Linux distros.
    • Supported Ubuntu versions

    

    Ubuntu Precise 12.04 (LTS) (64-bit) 

    Ubuntu Raring 13.04 and Saucy 13.10 (64 bit)
    

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19. Installation: boot2docker
    • On Mac

    

    $ brew install boot2docker

    $ boot2docker init

    $ boot2docker up

    $ export DOCKER_HOST=tcp://

    $ docker run -i -t busybox sh

    #/
    

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20. Installation: Vagrant
    • Clone the docker repository 

    $ git clone https://github.com/dotcloud/docker.git
    • Startup the vagrant image 

    $ vagrant up
    • SSH into the image 

    $ vagrant ssh
    • Use docker in VM

    $ docker
    • Vagrant client works on Mac
    

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21. Demo
    

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22. • Downloaded the image from docker repo
    • Generated a new LXC container
    • Created a new file system
    • Mounted a read/write layer
    • Allocated network interface
    • Setup IP Setup NATing
    • Executed the bash shell in the container
    • ** All under a very few minutes
    What Docker has done?
    

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23. Advantages
    • Elegant application delivery
    • Throwable sandboxes
    • Create uniform development & production environments
    • Automated testing and continuous integration/deployments
    • Deploying and scaling web apps, databases and backend services
    

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24. Why developers care?
    • Build once, write everywhere
    • Clean, safe, hygienic and portable runtime environment for app
    • No worries about missing dependencies during subsequent
    deployments
    • Reduce / eliminate compatibility concerns on different platforms
    

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25. Recommended workflow
    • Each service will be in its own container(s)
    • Build an image for each service
    • Pin dependencies (packages etc.) accurately.
    • Link services together
    

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26. Questions
    

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27. Thank you !!!
    Follow me on Twitter
    @anildigital
    

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