From zero to Docker

This is a simple presentation I held about Docker in the Linux User Group of my town.

Transcript

1. From zero to
   Docker
   Giovanni Toraldo
   @ LuccaLUG
   

   View Slide

2. Docker: what is it?
   Enables software developers to:
   ● package an application
   ● with all dependencies
   ● runs it everywhere unchanged
   

   View Slide

3. Docker: what is it?
   Enables system administrators to
   ● simplify application deployment
   ● ease scale-up & scale-down
   ● processes separation
   

   View Slide

4. Underlying technologies
   ● Linux namespaces
   ● Control Groups (cgroups)
   ● Layered filesystems
   ● LXC (now libcontainer)
   

   View Slide

5. View Slide

6. Glossary
   ● Image: immutable snapshot of a container,
   push/pull repository
   ● Container: an instance launched from an image
   ● Volume: persistent writable area of a container
   ● Registry: repository of images (versioned via
   tags)
   ● Dockerfile: the descriptor from which an image
   is built
   

   View Slide

7. How to install docker engine
   ● GNU/Linux
   deb https://apt.dockerproject.org/repo ubuntu-trusty main
   deb https://apt.dockerproject.org/repo debian-jessie main
   pacman -S docker
   ● Windows / OSX
   https://www.docker.com/products/docker-toolbox
   

   View Slide

8. View Slide

9. Docker-machine
   Machine manager (like Vagrant)
   https://github.com/docker/machine
   (Win/Mac: distributed in Docker toolkit)
   ● Launch VM somewhere
   ● Install Docker
   ● Generates and copy certificates
   ○ (password-less auth)
   ● Enable remote access via TCP
   

   View Slide

10. Docker-machine backends
    Where nodes can run?
    ● Generic backend
    ○ existing hosts with ssh access
    ● Local machine (virtualization)
    ○ Virtualbox
    ○ VMware Fusion
    ● Cloud providers
    ○ Amazon
    ○ GCE
    ○ Rackspace
    ○ DigitalOcean
    ○ ...
    

    View Slide

11. Docker-machine bootstrap examples
    $ docker-machine create --driver generic --generic-ip-address=
    
    $ docker-machine create --driver virtualbox
    $ docker-machine create --driver digitalocean --digitalocean-access-token
    
    $ docker-machine create --driver amazonec2 --amazonec2-access-key --
    amazonec2-secret-key
    $ docker-machine create --driver kvm --kvm-cpu-count 2 --kvm-disk-size 20 --kvm-
    memory 4096
    

    View Slide

12. Interaction with a Docker-machine node
    $ docker-machine env default
    export DOCKER_TLS_VERIFY="1"
    export DOCKER_HOST="tcp://192.168.99.100:2376"
    export DOCKER_CERT_PATH="/home/gionn/.docker/machine/machines/default"
    export DOCKER_MACHINE_NAME="default"
    # Run this command to configure your shell:
    # eval "$(docker-machine env default)"
    $ docker info
    Kernel Version: 4.1.17-boot2docker
    Operating System: Boot2Docker 1.10.0 (TCL 6.4.1); master : b09ed60 - Thu Feb 4
    20:16:08 UTC 2016
    

    View Slide

13. Hello world
    $ docker run -ti ubuntu:14.04 /bin/bash
    ● Live demo time
    

    View Slide

14. What happens under the hood?
    ● Pulls the ubuntu image from registry
    ● Creates a new container
    ○ Allocates a rw filesystem
    ○ Allocates a network interface (on a bridge)
    ○ Sets up network (IP address, dns..)
    ● Launch a process in the container
    ● Captures and provides application output
    Container terminates when the process exit
    

    View Slide

15. Dockerfile (not the best example)
    

    View Slide

16. Standard workflow
    Build & push:
    ● docker build -t gionn/nodejs-app:1.0.0 .
    ○ a tagged image is generated
    ● docker push gionn/nodejs-app:1.0.0
    ○ publish to repository
    Pull & run:
    ● docker pull gionn/nodejs-app:1.0.0
    ○ fetch from repository
    ● docker run gionn/nodejs-app:1.0.0
    ○ run container from this image
    

    View Slide

17. Docker compose
    Compose is a tool for defining and running multi-container
    Docker applications using a file in YML format.
    $ docker-compose up
    Examples:
    https://github.com/ClouDesire/docker-compose-library
    

    View Slide

18. Thanks!
    

    View Slide