Docker Paris meetup #1 – 10/02/2013

Victor Vieux, dotCloud Inc. @vieux

Outline

•  Intro to Docker •  Installing Docker •  Basic commands •  Demo: Simple deployment •  Questions

Quick survey

•  How many people have heard of Docker before this Meetup ?

•  How many people have tried Docker ? •  How many people are using Docker in

production ?

Introduction to Docker

Origins of Docker •  Docker is a rewrite of similar code that

currently powers the dotCloud PaaS •  Original version written in Python (like

dotCloud PaaS), now written in Go •  It’s a young project (~6 months), but with a

huge community.

Docker Timeline •  January 2013 Docker started as an internal project

inside of dotCloud •  March 21, 2013 Solomon gives Docker lightning

talk a PyCon US •  March 27, 2013 Docker 0.1 released to Public •  September 4, 2013 Docker merged into Openstack

for the Havana release •  September 19, 2013 Partnership with Red Hat

around OpenShift •  September 27, 2013 Docker 0.6.3 released

In the first 6 months

•  6000+ Github stars •  150+ Contributors •  50,000+ docker index pull •  100’s of projects built on top of Docker – UIs (DockerUI, Shipyard, Dockland…) – Open Source PaaS (DEIS, Flynn, Dokku…) – Continuous Deployment (Strider…)

•  1700’s Dockerized applications on Github

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 test on a laptop can run at scale, in production, on VMs, OpenStack cluster, public clouds and more.”

How does Docker work ?

•  LinuX Containers (LXC) •  Control Groups & Namespaces •  AUFS •  Client – Server with an HTTP API

LinuX Containers (LCX) •  Let’s your run a Linux system within another

Linux system •  A container is a group of processes on a

Linux box, put together is an isolated environment

•  From the inside, it looks like a VM •  From the outside, it looks like normal

processes •  “chroot on steroids”

Why Containers?

•  Speed: Boots in seconds •  Footprint: 100-1000 containers on one

machine. Small disk requirements

Containers vs. VMs

Control Groups & Namespaces Linux kernel feature to limit, account and isolate resource usage, such as: – CPU – Memory – Disk I/O

AUFS  •  File system that implements union mount.      •  Supports Copy On Write (COW):    

 # mount –t aufs –o br=/files1:/files2 none /files    

 # mount –t aufs –o br=/tmp=rw:/bin=ro none /files    

Installing Docker

Requirements

•  Linux Kernel 3.8 or above •  AUFS •  LXC •  64-bit

Installations

•  Ubuntu Linux •  Binaries •  Using Vagrant

More on: http://docs.docker.io/en/latest/installation

Installation: Ubuntu Linux •  AUFS support $> sudo apt-get update $> sudo apt-get intall linux-image-extra-`uname –r`

•  Add Docker repository $> sudo sh –c “curl https://get.docker.io/gpg | apt-key add -” $> sudo sh –c “echo deb http://get.docker.io/ubuntu docker \

main > /etc/apt/sources.list.d/docker.list”

•  Install $> sudo apt-get update $> sudo apt-get install lxc-docker

Installation: Binaries •  Get the docker binary $> wget –output-document=docker https://get.docker.io/builds/\

Linux/x86_64/docker-latest $> chmod +x docker

•  Run the docker daemon $> sudo ./docker –d &

•  Use your own system startup script  

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

•  Docker client works on Mac

Basic  commands  

Classic: hello world •  Get one base image (ubuntu, centos, busybox,…) $> docker pull ubuntu

•  List images on your system $> docker images

   •  Print hello world $> docker run ubuntu:12.10 echo “hello world”

 

Detached mode •  Run  in  Docker  using  the  detach  flag  (-­‐d)  $> docker run –d ubuntu sh –c “while true; do echo hello world; sleep 1; done”

•  Get  container’s  id  $> docker ps

•  A:ach  to  the  container  $> docker attach <container_id>

 •  Stop/Start/Restart  the  container  $> docker stop <container_id>

 

Containers vs Images •  Remove a file from an image $> docker run busybox rm /etc/passwd

•  The file is still there ?? $> docker run busybox cat /etc/passwd

•  Commit the newly created to an image $> docker ps –n=2 #get the container’s id $> docker commit <id> vieux/broken-busybox

 •  The file is gone $> docker run vieux/broken-busybox cat /etc/passwd

 

Public Index & Network •  Pull an apache image from the public index $> docker search apache $> docker pull creack/apache2

•  Run the image and check the ports $> docker run –d creack/apache2 $> docker ps

•  Expose public ports $> docker run –d –p 8888:80 –p 4444:443 creack/apache2 $> docker ps

 

Creating your 1st app: the interactive way

•  Using docker in interactive mode $> docker run –i –t ubuntu bash root@82c63ee50c3d:/# root@82c63ee50c3d:/# apt-get update […] root@82c63ee50c3d:/# apt-get install memcached […] root@82c63ee50c3d:/# exit

•  Commit the image $> docker commit `docker ps –q –l` vieux/memcached

•  Start the image $> docker run –d –p 11211 –u daemon vieux/memcached memcached

 

Creating your 1st app: the boring way

•  Multiple run / commit $> docker run ubuntu apt-get update $> $ID=(docker commit `docker ps –q –l`) $> docker run $ID apt-get install memcached $> docker commit `docker ps –q –l vieux/memcached

•  Define default configuration at commit $> docker commit –run=‘{“Entrypoint”: [“memcached”]}’ […]

•  Start the image $> docker run –d –p 11211 –u daemon vieux/memcached

 

Creating your 1st app: the scripted way

•  Write a Dockerfile # Memcached FROM ubuntu MAINTAINER Victor Vieux <victor@dotcloud.com> RUN apt-get update RUN apt-get install –y memcached ENTRYPOINT [“memcached”] USER daemon EXPOSE 11211

•  Buid the image $> docker build –t=vieux/memcached .

•  Start the image $> docker run –d vieux/memcached memcached

Volumes and bind mounts

•  Put your persistent data in a volume $> $ID=(docker run –d –v /var/lib/mysql vieux/mysql)

•  So you can re use it in another container $> docker run –d –volumes-from=$ID vieux/mysql

 •  Bind mounts $> docker run –d –v /home/vv:/home <image>

•  Supports read only / read write $> docker run –d –v host/path:container/path:rw <image>

Other commands

•  docker cp #copy a file from container to host

•  docker diff #print container changes

•  docker top #display running processes inside a container

•  docker rm/rmi #delete container/image

•  docker wait #wait until container stop and print exit code

More on: http://docs.docker.io/en/latest/commandline/cli

Demo: Simple deployment

Local development

•  App running in prod http://ks3100989.kimsufi.com:8080/

•  Build local  $> docker build –t=gcm .

•  Test local $> docker run –p 49200:8080 gcm  http://localhost:49200

•  Change some files •  Rebuild & test

$> docker build –t=gcm . $> docker run –p 49200:8080 gcm

Push to prod

•  Tag image in order to push it $> docker tag gcm ks3100989.kimsufi.com:5000/gcm

•  Push image to local registry $> docker push ks3100989.kimsufi.com:5000/gcm

•  On production server, download image $> docker pull ks3100989.kimsufi.com:5000/gcm

•  Restart the container $> docker stop <container_id> $> docker run –d –p 8080:8080 <image>

Questions ?

Thank you!

@vieux