Cool Things About Docker

Theo Pak

Cimpress Infrastructure Core Engineering Lightning Talk: Wed Sept 30, 2015 @ 10:30am in Waltham, MA.

Transcript

1. Cool Things About Docker
   Theo Pak
   
   tpak@cimpress.com
   
   twitter.com/theopak
   

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2. Linux Containers
   • A container is an isolated, 

   resource controlled, portable environment 

   for your application
   
   • Containers are lightweight
   
   • Microservices ❤ Containers
   
   • Linux containers prd ready on Docker 1.5
   
   • Windows containers coming in 

   Windows Server 2016
   

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3. Virtual Machines Containers
   Code that describes entire
   machines.
   Code that describes the
   application environment.
   

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4. Containers
   Containers are perfect for
   microservices
   
   - faster deployments
   
   - near zero startup penalty
   
   - highly automatable
   
   - resource, network,
   content isolation
   
   - dependency isolation
   Code that describes the
   application environment.
   

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5. Build an Image
   Infrastructure as code: Containers are 

   your exact environment (but not a whole VM).

   $ git add Dockerfile

   $ git commit -m “Dev and Ops run the same Dockerfile”
   
   A Dockerfile defines a container image. 

   Images layer additively.

   $ cat Dockerfile

   FROM ubuntu

   RUN apt-get -y install ruby ruby-dev sensu

   COPY ./dist /var/my_app/

   EXPOSE 80

   CMD ["./start.sh"]
   
   Linux Containers are lightweight and perfect for microservices. 

   Virtually zero added cost to application startup/restart.

   $ docker build # build an image from the Dockerfile

   $ docker run # run an instance of an image
   

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7. Run an Image as a Container
   • No different DEV, CIT, PRD environments
   
   • Exactly one environment: the container
   
   • The same container runs on 

   your machine, Jenkins, AWS, etc
   
   • Expect your build to be identical on localhost, Jenkins, and prd.
   
   • Now, your source repo captures as much as possible about the
   application.
   
   • DevOps people are experts. Use their images as base.
   

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8. puppet apply inside a container
   Use Puppet? Consul, Vagrant, Terraform? Auspice?
   
   You can get some of the benefits of containers in combination
   with complimentary tools.
   
   COPY puppet /etc/puppet

   RUN cd /etc/puppet \

   && librarian-puppet update

   RUN puppet apply /etc/puppet/manifests/default.pp \

   —-modulepath=‘/etc/puppet/modules' \

   --hiera_config='/etc/puppet/hiera.yaml'
   

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9. Container-Oriented Design
   • Containers are isolated, resource-controlled, and portable
   
   • Containers are lightweight: you can run more containers than
   VMs on the same hardware
   
   • Containers are instances of Images. 

   Images are made of other Images.
   
   • You can get some of the benefits of containers in combination
   with a configuration managed by Puppet
   

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10. Docker
    Build, Ship, Run
    

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