1. inBloom, Inc.
Server to Cloud
Convert a legacy platform to a micro-PaaS using Docker
Todd Fritz
April 15. 2014

2. inBloom, Inc.
Agenda
• Whoami
• Important Announcement
• Background
• Containers
• Create Local Environment
• Using Vagrant
• Using Docker
• Graphical Interfaces for Docker
• Shipyard
• Two Container Example
• Advanced Docker
• Questions
• References
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3. inBloom, Inc.
Whoami
Bio: http://www.linkedin/com/in/tfritz
• Software Architect at inBloom
 The opinions contained within this presentation may not represent my employer, but
I think they should.
• Evangelist of layered, distributed, Message-oriented-Middleware
• Current focus is middleware through caching, noSQL data store
• Exposed to different companies, projects, people and technologies
• Novice bass player
• Recent father of a five month old
• Scuba diver; next adventure:
 https://www.bikiniatoll.com/divetour.html
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No sleep for you!

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Important Announcement
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5. inBloom, Inc.
Today is April 15th...
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And, I am not a Dev Ops specialist.
Just took an interest and within a few weeks this is
what I learned.
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Background
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8. inBloom, Inc.
Note: This presentation will available via slideshare after
today.
This talk is part two of:
 http://www.slideshare.net/ToddFritz/2014-04-03legacytocloud
 Presented at Great Wide Open, April 3, 2014
Some files used while compiling this presentation
 https://github.com/inbloom/AJUG-2014-04-15-docker
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Approach the Legacy Monolith
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I’m a proud stovepipe,
just bolted together,
vroom vroom vroom vroom vroom.

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Decompose the Monolith
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Oh, nooo... My
job security...

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Assemble a Decoupled, Modular System
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I have free weeknights
and weekends now...

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Replacing a legacy system. Decompose. Analyze.
Employ an iterative methodology
 Leverage existing knowledge and literature
 Some analysis before
 Decompose and modularize (scale cube)
 Separation of concerns
 Proof of concepts are your friend
Deployment environments
 Private servers
 Cloud (private, public)
 Hybrid
Platform architectures
 Legacy
 PaaS
 xPaaS
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xPaaS Topology
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https://img.en25.com/Web/RedHat/JB_xPaaS_Tech_Overview_11454037_v3_0913cd_web.pdf
Enables specialization, layering, separated concerns, decoupling

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Containers
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Container Technologies (VEs)
• Warden (Cloud Foundry)
 https://github.com/cloudfoundry/warden
• Docker (from dotCloud, cloudlets)
 https://www.docker.io/
• Google LMCTFY (let me contain that for you)
 https://github.com/google/lmctfy
 december, 2013
• OpenVZ
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Virtual Environment (Container)
vs. Virtual Machine
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http://www.slideshare.net/dotCloud/docker-intro-november

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Docker (per Wikipedia) (1/2)
Docker:
• Automates the deployment of applications inside
software containers.
• Extends Linux Containers (LXC) with a high-level API
to provide a lightweight virtualization solution that runs
processes in isolation.
• Utilizes LXC, cgroups, and the kernel itself –
• Unlike traditional virtual machines it does not include a
separate operating system.
• Kernel provides resource isolation (CPU, memory,
block I/O, network, etc.) and separate namespaces to
completely isolate application's view of the operating
environment.
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18. inBloom, Inc.
Docker (per Wikipedia) (2/2)
Docker containers can be used to extend distributed
systems so they run autonomously on a single
physical machine, or with a single instance per node.
Enables nodes to be deployed as resources are
available to provide a seamless platform as a service
(PaaS) – style deployment for systems like Apache
Cassandra, Riak and related distributed systems.’
Integrates with Chef, Puppet, Vagrant, Nova, etc.
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More
Docker is a micro container framework for PaaS
• https://www.docker.io/learn_more/
• Open-source
• Easier scalability
• Lightweight, portable, insulated containers
• Reusable from dev (“local cloud”) through production
• Can run at scale on VMs, bare metal, cloud; virtually
anywhere
• Encapsulate any payload (application)
• Run consistently on and between virtually any server
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http://www.slideshare.net/dotCloud/docker-intro-november

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How it Works
• Docker builds on lxc which offers system-level virtualization and has existed since
linux 2.6.32 (December, 2009) – but prefer kernel 3.8+
• Docker has three parts
 docker daemon runs as root to manage containers
 docker containers spawn from images, which are tiny and can be versioned
 docker repository allows images to be exchanged and versioned like code
(public or private)
• Each container has its own ip address
• Link exposed ports and variables across containers through configuration using
abassador containers to avoid hard coding (svendowideit):
 consumer  redis-ambassador  redis
• Port and pipework to expose containers outside host
• Can share volumes, multi home, integrate containers into host network, and much
more (ajug)
• Continuous integration can generate versioned docker images, web hooks, repo
notifications
• Supervisor management tool to manage processes within container
(http://supervisord.org/introduction.html)
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Docker Uses
• Common use cases:
 Automate application packaging and deployment
 Lightweight PaaS environments
 Automate testing, continuous integration, and deployment
 Deploy and scale web apps, databases, backend services
• Growing adoption since dec 2013
• Red Hat fast-tracks Docker apps for enterprise Linux
 http://www.infoworld.com/t/application-virtualization/red-
hat-fast-tracks-docker-apps-enterprise-linux-238122
• Production ready deployment planned for December, 2014.
 Support services planned for early 2015
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Reusable Containers and Cook Books
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http://www.slideshare.net/dotCloud/docker-intro-november
A Docker container image may already exist

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Docker Basics
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http://www.slideshare.net/dotCloud/docker-intro-november
Artifactory for virtualization images?

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Docker Images
• The basic building block of a Docker container
• Analogous to a slice of a VM image, containing
application code or binaries, as well as the execution
environment and dependencies
• Images may be built atop each other
• An image contains only the incremental changes
required to transform its base image to the state
required by the image
• May contain metadata, such as how to run what is
inside the image, expose ports, etc
• Acts as an instantiable container template
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Docker Containers
• The result of starting a running process from an
image and its dependencies
• Represent a single process or service
• Intra-container communication via sockets (Docker
links). Containers can talk to each other.
• Familiar lifecycle: started, stopped, or kill
• Can create images from previously run
containers, to persist changes made while
container was executing
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New in Docker 0.9
• Execution driver API
 Customize execution environment around container; enables
use of other isolation tools
• Built in execution container – libcontainer
 Alongside LXC, boosts stability, insulates Docker from different
versions of LXC
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But...we have Chef (or <other>)...
(Do not upset Dev Ops, ever...)
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Step Away from the Ledge...
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Image from the movie “The Lair of Filth” – no pun intended...

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Chef & Docker
• Docker is new and not ready for Production (yet)
• Docker is for light Virtual Images
• Chef for Virtual Machines
• Chef is tried and true
• Chef proven for provisioning VMs or changes to
existing machines (small or complex)
• Chef and Docker can be used together
 Example: The Deis framework scales Chef nodes and
Docker containers. But both are new.
 Several other options including Tsuru (open source PaaS)
• Docker useful to encapsulate applications or services
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“The Docker Book”
Not yet released, but available for pre-order
http://www.dockerbook.com/
1. Introduction to Docker
2. Installing Docker
3. Getting started with Docker
4. Working with Docker images and repositories
5. Testing with Docker
6. Building services with Docker
7. Using the Docker API
8. Extending Docker
Also useful
http://kencochrane.net/blog/2013/08/the-docker-guidebook/
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Docker Deep Dive

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Create Local Environment
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Install Prerequisites
• Talk will focus on VM which fits more deployment scenarios
• Install VirtualBox (4.3.x)
 https://www.virtualbox.org/
 Download and install into Host OS
• Github repo for demo
 https://github.com/inbloom/AJUG-2014-04-15-docker.git
• Install Vagrant (1.5.x) – used for this talk
 http://www.vagrantup.com/
 Download and install into Host OS
 Available Boxes: http://www.vagrantbox.es/
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Running Docker
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Common use case is to run within a VM
 Optional if host OS is Linux (e.g. Ubuntu)
 Benefit: A configured VM can be exported
 OS X users can try boot2docker
• “lighter” than VM, uses tiny core linux (24 Mb)
• brew install boot2docker
• https://github.com/boot2docker/boot2docker/
• Has limitations so not used in this talk (better for PoCs)
• https://github.com/boot2docker/boot2docker/blob/master/
README.md

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Create an Account with the Docker Index
https://index.docker.io/account/signup/
Sure looks like Maven Central. Versioned containers.
From a host with Docker installed:
$ docker login
Username (): myusername
Password:
Email (): myusername@example.com
Login Succeeded
credentials are stored after login
~/.dockercfg
/var/lib/docker/.dockercfg
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Search the Index
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Search the Docker Index for images to reuse. (You may find places to contribute
back images to the open source public repository.)

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Command Line Search
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Use search and be curious, for example, what has the founder of Docker pushed?
You can download containers to reuse or examine contents for ideas.

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Pull an Image
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The index figures out the details.
Can also push images, etc.

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Create a Private Repo
https://github.com/dotcloud/docker-registry
git clone https://github.com/dotcloud/docker-registry.git
cd docker-registry
cp config_sample.yml config.yml
pip install -r requirements.txt
gunicorn --access-logfile - --log-level debug --debug -b
0.0.0.0:5000 -w 1 wsgi:application
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Configure Private Repo
https://github.com/dotcloud/docker-registry/blob/master/README.md
http://blog.docker.io/2013/07/how-to-use-your-own-registry/
cp config/config_sample.yml config/config.yml
Example config:
prod:
loglevel: warn
storage: s3
s3_access_key: _env:AWS_S3_ACCESS_KEY
s3_secret_key: _env:AWS_S3_SECRET_KEY
s3_bucket: _env:AWS_S3_BUCKET
storage_path: /srv/docker
smtp_host: localhost
from_addr: docker@myself.com
to_addr: my@myself.com
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43. inBloom, Inc.
Pull from Public Push to Private Repo
# First, make sure you have the "ubuntu" repository:
docker pull ubuntu
# Find the image id that corresponds to the ubuntu repository
docker images | grep ubuntu | grep latest
ubuntu latest 8dbd9e392a96 12 weeks ago 263 MB (virtual
263 MB)
# Tag to create a repository with the full registry location.
# The location becomes a permanent part of the repository
name.
docker tag 8dbd9e392a96 localhost.localdomain:5000/ubuntu
# Finally, push the new repository to its home location.
docker push localhost.localdomain:5000/ubuntu
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44. inBloom, Inc.
Dockerfiles
• Dockerfiles are used to build containers by scripting
actions to make up each layer of an image
• Not as powerful as traditional configuration
management software
• For example, in discrete steps you can instruct Docker
to build an image by taking a default Ubuntu image,
apt-get installing several dependencies, and then
adding your application code. Each Dockerfile
command creates a new image layer, and clever
structuring of the commands will allow them to
becached and re-used.
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45. inBloom, Inc.
Anatomy of a Dockerfile (1/2)
https://www.docker.io/learn/dockerfile/level1/
# Always comment your code
FROM ubuntu
MAINTAINER Uncle Sam, uncle.sam@irs.gov
RUN echo "deb http://archive.ubuntu.com/ubuntu precise main
universe" > /etc/apt/sources.list
RUN apt-get update
RUN apt-get install -y memcached
The first line in a Dockerfile is FROM, which defines the base image (e.g.
obtained via a docker search).
RUN instructions execute any command against the current image and
commits. Commands can be layered to conform to version control paradigms.
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46. inBloom, Inc.
Anatomy of a Dockerfile (2/2)
https://www.docker.io/learn/dockerfile/level2/
The ENTRYPOINT instruction triggers a command when the container
starts
# Launch memcached when launching the container
ENTRYPOINT ["memcached", "-u", "daemon"]
May want ENTRYPOINT instructions to run as user other than root.
ENTRYPOINT ["memcached"]
USER daemon
The EXPOSE instruction exposes a port outside the container
EXPOSE 11211
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Building an Image from a Dockerfile
If Dockerfile is in current directory
docker build .
From stdin
docker build - < Dockerfile
From github
docker build github.com/creack/docker-firefox
Then, do a “docker images” to view
REPOSITORY TAG ID CREATED SIZE
ubuntu 12.04 8dbd9e392a96 4 months ago 131.5 MB
(virtual 131.5 MB)
<none> <none> 1dcfa24c8ca6 About a minute ago 52.27 MB
(virtual 183.8 MB)
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Name the New Image
The new image lacks a name, so give it one
docker tag 1dcfa24c8ca6 memcached
Using the –t with build removes the added step
docker build -t memcached .
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49. inBloom, Inc.
Create VM
clone git repo for this talk (OS X example)
$ cd ~/Projects
$ git clone git://github.com/inbloom/AJUG-2014-04-
15-docker.git
$ cd AJUG-2014-04-15-docker/01_create_env
Create VM using provided Vagrantfile
 Preconfigured to setup Docker
 Vagrant’s Docker Provisioner is your friend
• http://docs.vagrantup.com/v2/provisioning/docker.html
 http://blog.phusion.nl/2013/11/08/docker-friendly-vagrant-boxes/
$ vagrant up
$ vagrant ssh
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Vagrantfile (1/2)
# -*- mode: ruby -*-
# vi: set ft=ruby :
# Vagrantfile API/syntax version. Don't touch unless you know
what you're doing!
VAGRANTFILE_API_VERSION = "2"
Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
config.vm.box = "phusion-open-ubuntu-12.04-amd64"
config.vm.box_url = "https://oss-
binaries.phusionpassenger.com/vagrant/boxes/ubuntu-12.04.3-
amd64-vbox.box"
config.vm.box_check_update = true
config.vm.provider "virtualbox" do |v|
v.name = "docker1"
v.memory = 8192
v.cpus = 4
end
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Vagrantfile (2/2)
if
Dir.glob("#{File.dirname(__FILE__)}/.vagrant/machines/default/*/id").empty?
# Install Docker
pkg_cmd = "wget -q -O - https://get.docker.io/gpg | apt-key add -;"
"echo deb http://get.docker.io/ubuntu docker main >
/etc/apt/sources.list.d/docker.list;"
"apt-get update -qq; apt-get install -q -y --force-yes lxc-docker; ”
# Add vagrant user to the docker group
pkg_cmd << "usermod -a -G docker vagrant; ”
config.vm.provision :shell, :inline => pkg_cmd
end
end
Vagrant.configure("2") do |config|
for i in 8000..9000
config.vm.network "forwarded_port", guest: i, host: i
end
end
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Using Vagrant
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Vagrant CLI (1/4)
A brief overview of Vagrant commands; not intended
to replace other Production tools.
Usage
$ vagrant [options] <command> [<args>]
-v, --version Print the version and exit.
-h, --help Print this help.
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Vagrant CLI (2/4)
Common commands
box manages boxes: installation, removal, etc.
connect connect to a remotely shared Vagrant environment
destroy stops and deletes all traces of the vagrant machine
halt stops the vagrant machine
help shows the help for a subcommand
init initializes a new Vagrant environment by creating a Vagrantfile
login log in to Vagrant Cloud
package packages a running vagrant environment into a box
plugin manages plugins: install, uninstall, update, etc.
provision provisions the vagrant machine
reload restarts vagrant machine, loads new Vagrantfile configuration
resume resume a suspended vagrant machine
share share your Vagrant environment with anyone in the world
ssh connects to machine via SSH
ssh-config outputs OpenSSH valid configuration to connect to the machine
status outputs status of the vagrant machine
suspend suspends the machine
up starts and provisions the vagrant environment
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Vagrant CLI (3/4)
For help on any individual command
vagrant <command> -h
Or to see subcommand features
vagrant box <subcommand> -h
To see all subcommands
vagrant list-commands
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Vagrant CLI (4/4)
$ vagrant package –h
Usage: vagrant package [options] [name]
Options:
--base NAME Name of a VM in virtualbox to package as a base box
--output NAME Name of the file to output
--include FILE... Additional files to package with the box
--vagrantfile FILE Vagrantfile to package with the box
-h, --help Print this help
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Vagrant Plugins
vagrant plugin install --plugin-source
https://rubygems.org --plugin-
prerelease vagrant-vbguestvagrant
vagrant plugin install vagrant-winnfsd
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Export a Vagrant Box
Once your VM is setup and configured, you can create
an image from it
$ vagrant package --base my_base_box
To export a Vagrant box
$ vagrant box add my_box package.box
$ mkdir test_environment
$ cd test_environment
$ vagrant init my_box
$ vagrant up
$ vagrant ssh
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Install Docker
whale you be my container?
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Installation
It already is...
(starting with a “bare” base box may required more
effort to setup the OS, install components)
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Verify the Installation
vagrant@ubuntu-12:/vagrant$ docker info
Containers: 0
Images: 0
Storage Driver: aufs
Root Dir: /var/lib/docker/aufs
Dirs: 0
Execution Driver: native-0.1
Kernel Version: 3.8.0-35-generic
vagrant@ubuntu-12:/vagrant$ docker pull busybox
vagrant@ubuntu-12:/vagrant$ docker info
Containers: 0
Images: 4
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Testing Docker
Hello World
http://docs.docker.io/en/latest/examples/hello_world/
vagrant@ubuntu-12:/vagrant$ sudo docker pull busybox
docker run busybox /bin/echo hello world
C1=$(sudo docker run -d ubuntu /bin/sh -c "while
true; do echo hello world; sleep 1; done”)
docker ps list
docker logs `C1`
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Docker Container Lifecycle
docker run creates a container.
docker stop stops it.
docker start will start it again.
docker restart restarts a container.
docker rm deletes a container.
docker kill sends a SIGKILL to a container. Has issues.
docker attach will connect to a running container.
docker wait blocks until container stops.
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Container Info
Info
docker ps shows running containers.
docker inspect looks at all the info on a container (including IP address).
docker logs gets logs from container.
docker events gets events from container.
docker port shows public facing port of container.
docker top shows running processes in container.
docker diff shows changed files in the container's FS.
Import / Export
No easy way to use Docker to import files into a container filesystem
• Could use something like Cargo within a container to push in artifacts
docker cp copies files or folders out of container filesystem
docker export creates tarball from container filesystem
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Docker Image Lifecycle
docker images shows all images
docker import creates an image from a tarball
docker build creates image from Dockerfile
docker commit creates image from a container
docker rmi removes an image
docker insert inserts a file from URL into image. (kind of odd, you'd think
images would be immutable after create)
docker load loads an image from a tar archive as STDIN, including images and
tags (as of 0.7)
docker save saves an image to a tar archive stream to STDOUT with all parent
layers, tags & versions (as of 0.7)
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15 Docker Tips
http://www.centurylinklabs.com/15-quick-docker-tips
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Graphical Interfaces for Docker
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Two main options for a graphical UI to manage
Docker
 Shipyard
• https://github.com/shipyard/shipyard/wiki/QuickStart
 DockerUI
• https://github.com/crosbymichael/dockerui
Shipyard allows containers to be
managed, linked, and inspected via a UI
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Shipyard
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Shipyard features
• Multiple host support
• Create / Delete containers
• View Images
• Build Images (via uploaded Dockerfile or URL)
• Import repositories
• Private containers
• Container metadata (description, etc.)
• Applications: bind containers to applications that are setup
with hipache
• Attach container (terminal emulation in the browser)
• Container recovery (mark container as "protected" and it
will auto-restart upon fail/destroy/stop)
• RESTful API
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Shipyard (1/2)
1 line to install within a docker host:
docker run -i -t -v
/var/run/docker.sock:/docker.sock shipyard/deploy
setup
Shipyard Stack Deployed
You should be able to login with
http://<docker-host-ip>:8000
admin:shipyard
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Shipyard (2/2)
Within each container to shipyard manage you will also need to setup and register the Shipyard Agent.
See http://github.com/shipyard/shipyard-agent for details.
Download to the host:
sudo curl https://github.com/shipyard/shipyard-
agent/releases/download/v0.2.5/shipyard-agent -L -o /usr/local/bin/shipyard-agent
sudo chmod +x /usr/local/bin/shipyard-agent
Register the host:
./shipyard-agent -url http://myshipyardhost:shipyardport -register
vagrant@ubuntu-12:/usr/local/bin$ ./shipyard-agent -url http://0.0.0.0:8000 -
register
2014/04/14 02:27:48 Using 10.0.2.15 for the Docker Host IP for Shipyard
2014/04/14 02:27:48 If this is not correct or you want to use a different IP, please
update the host in Shipyard
2014/04/14 02:27:48 Registering at http://0.0.0.0:8000
2014/04/14 02:27:48 Agent Key: 597d7d4db3d44daca47ff114e48144d2
Register a host with the shipyard deployment.
shipyard-agent -url http://my-shipyard-host:port -key
597d7d4db3d44daca47ff114e48144d2
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Containers

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Container (Redis)

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Container (Redis logs)

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Images

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Applications

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Container Console

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Two Container Example
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Linking Containers
Links allow containers to communicate through TCP/IP ports.
Suppose we start a container that exposes port 1337
docker run -name CONTAINER
docker run -d -link CONTAINER:ALIAS -name LINKED
user/wordpress
Exposed ports and aliases of parent will show up in child container
$ALIAS_PORT_1337_TCP_PORT
$ALIAS_PORT_1337_TCP_ADDR
More robust example (many more can be found via Googling)
http://blogs.atlassian.com/2013/11/docker-all-the-things-at-atlassian-automation-and-wiring/
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About Ambassador Containers
Encourage portability by avoiding hardcoding and linking
via an ambassador.
(consumer) -> (redis-ambassador) --network--> (redis-ambassador) ->
(redis)
• Avoids restarting a consumer to attach to a different service
• Restart the client ambassador container that the consumer
is connected to, to rewire a consumer to talk to a different
service
• This pattern allows a transparent transition to to a different
docker host for a consumer
http://docs.docker.io/en/latest/use/ambassador_pattern_linking/
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Ambassador Container Linking
- Host A: Startup Redis
big-server $ docker run -d --name redis crosbymichael/redis
- Host A: Add ambassador linked to Redis
big-server $ docker run -d --link redis:redis --name
redis_ambassador -p 6379:6379 svendowideit/ambassador
- Host B: Add ambassador that sets env
client-server $ docker run -d --name redis_ambassador --
expose 6379 -e REDIS_PORT_6379_TCP=tcp://192.168.1.52:6379
svendowideit/ambassador
- Host B: Use Redis client container to talk to remote server
client-server $ docker run -i -t --rm --link
redis_ambassador:redis relateiq/redis-cli
redis 172.17.0.160:6379> ping
PONG
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Advanced Docker
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Load Balanced
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http://mdavey.wordpress.com/2014/01/07/devops-docker/

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Distributed Producer-Consumer
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http://www.appneta.com/blog/automated-testing-with-docker/

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Docker and Open vSwitch (1/2)
• Docker and Open vSwitch for container isolation with VLANs
between 2 hosts running Open vSwitch
• Containers 1 & 3 are on VLAN 10 whereas containers 2 & 4 are on
VLAN 20
 1 & 3 can ping each other but cannot ping 2 or 4
• 4 bridges, 10 interfaces, 2 VLANs, 1 GRE tunnel and 4
containers.
• Starts in 1 second...
• Source (with code and cook book):
http://fbevmware.blogspot.com/2013/12/coupling-docker-and-open-vswitch.html
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Docker and Open vSwitch (1/2)
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PaaS Frameworks
• Deus
• CoreOS
• Flynn
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Flynn uses etcd
A highly-available key value store for shared configuration and service discovery.
etcd is an open-source distributed key value store that provides the backbone of CoreOS
clusters and the etcd client runs on each machine in a cluster. etcd gracefully handles master
election during network partitions and the loss of the current master.
Your applications can read and write data into etcd. Common examples are storing database
connection details, cache settings, feature flags, and more.
Features
• Simple, curl-able API (HTTP + JSON)
• Optional SSL client cert authentication
• Benchmarked 1000s of writes/s per instance
• Properly distributed using Raft protocol
• Keys support TTL
• Atomic test and set
• Easily listen for changes to a prefix via HTTP long-polling
https://coreos.com/using-coreos/etcd/
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Flynn uses Systemd
CoreOS uses systemd as the core of its distributed init system, fleet.
Systemd is well supported in many Linux distros, making it familiar to most
engineers. Every aspect of CoreOS is deeply integrated with systemd.
• Performance Systemd boots extremely fast, with our goal to keep it under 1s.
• Journal Systemd's logging journal has modern features such as JSON
export, forward sealing, and indexing for fast querying.
• Socket Activation While this might be a bit of a throw back to the inetd
days, we think socket activation is particularly useful for inter-service
dependency management.
Systemd has an extremely rich syntax that can describe the attributes of a particular
service. Your services can express hard or soft dependencies, the order of launch
relative to those dependencies, and identify conflicting services.
Docker containers are much easier to manage when you can specify whether they
automatically restart per container and customize the timing for restarting.
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Flynn uses Discoverd
A simple but powerful service discovery system written in Go. Backed by
etcd, but can be extended to use ZooKeeper or other distributed consistent
stores.
Discoverd lets your services find each other in a constantly changing
environment. With discoverd and a client you can:
• Register a service as online
• Locate online instances of a service
• Get notified when instances of a service change
• Determine a "leader" for any set of services
There are three pieces to the discoverd system:
• discoverd itself
• Client library and API
• Backend store (etcd, Zookeeper, etc)
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questions
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references
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reference material
https://www.docker.io/
http://deis.io/overview/
http://cjlarose.com/2014/03/08/run-docker-with-vagrant.html
http://www.vagrantup.com/
http://blog.docker.io/2014/04/docker-0-10-quality-and-ops-tooling/
http://docs.docker.io/en/latest/examples/hello_world/#running-examples
http://mesosphere.io/2013/09/26/docker-on-mesos/
https://medium.com/devops-programming/7f5fd023158f
http://docs-v1.vagrantup.com/v1/docs/base_boxes.html
http://docs.docker.io/en/latest/installation/ubuntulinux/
https://phunehehe.net/docker-vs-chef-vagrant/
http://www.centurylinklabs.com/top-10-startups-built-on-docker/
http://www.slideshare.net/julienbarbier42/building-a-saas-using-docker
http://coreos.com/blog/docker-dynamic-ambassador-powered-by-etcd/
https://github.com/shipyard/shipyard-agent
http://blog.docker.io/
http://blog.relateiq.com/why-docker-why-not-chef/
http://www.dockerbook.com/
http://www.centurylinklabs.com/building-complex-apps-for-docker-on-coreos-and-fig/
http://txt.fliglio.com/2013/12/service-discovery-with-docker-docker-links-and-beyond/
http://www.centurylinklabs.com/auto-loadbalancing-with-fig-haproxy-and-serf/
http://www.centurylinklabs.com/build-a-2-container-app-with-docker/
http://sysadvent.blogspot.com/2013/12/day-13-controlling-cluster-of-servers.html
http://txt.fliglio.com/2013/12/service-discovery-with-docker-docker-links-and-beyond/
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