be a happier developer with docker: tricks of the trade

Nicola Paolucci!Developer Advocate / Evangelist

with!

Happier Developerwith

Be a

Nicola Paolucci@durdn

Bio pictures: the subtle pleasure of embarrassing yourself in front of hundreds of people

Tools, Tips and Hacks

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3

The plan for this session:

Notes on Workflows and Techniques

1 Why does Docker make Developers happy?

Why?

Compulsion to have clean and perfect

environments

© www.elephantlifestyle.com

the need for speed of every developer with an idea

Fast application mobility, Real repeatability

Great for development team collaboration

Building blocks for your Micro-services Architecture

Micro-services Architecture Blueprint

@crichardson

!!!!!

Traditional Server-side web apps

View Controller

Model

API Gateway

!!!!!

Browser/Native App

View Controller

Model

REST

REST

REST

Product Info Service

Recommendation Service

Review Service

Single entry point

Protocol translationClient specific APIs

Workflows & Techniques

Workflow 1: Develop inside a single running container

As you would in a single VM

Container

Start a shell in container docker run -i -t ubuntu /bin/bash

Folder from host:!/src

Docker host

Host folder!/path/to/code

-v /path/to/code:/src

To use a container as a full Development Environment

phusion/baseimage

Workflow 2: Leverage containers, modularise

Techniques: Embrace Reusability in Dockerfiles

Write general requirements early, commit and name relevant checkpoints, leave customisations last

add + build routine magicTechniques:

docker add <src> <dest>

docker add <src> <dest>The ADD instruction copies new files from host’s <src> to container’s <dest>

docker build your image with updated code

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2

add + build routine magic?!

Update code in local app folder (git pull?)

Distribute and profit!3

Sharing data in containersTechniques:

Container

Folder from host:!/app

Docker host

Host folder!/opt/test-app

-v /opt/test-app:/app

host to containersshare folder from

host to containers

docker run -v /opt/test-app:/app \ -i -t ubuntu /bin/bash

Use the run -v (volume option) to specify host/container folder to be synced

From

is simple

Same pattern using Dockerfile

FROM busybox VOLUME ["/var/volume1", "/var/volume2"] CMD ["/bin/true"]

Common pattern: Data in containers

Docker host

/var/volume1

DATA

/var/volume2

Common pattern: data in containers

docker run -v /var/volume1 \ -v /var/volume2 \ --name DATA busybox true

Switched off, named, data container which exposes a folder

Data in containers pattern

Docker host

/var/volume1

DATA

/var/volume2

Data in containers pattern

Docker host

/var/volume1

DATA

/var/volume2

/var/volume1

client1

/var/volume2

--volumes-from DATA--volumes-from DATA

Common pattern: data in containers

docker run -t -i -rm --volumes-from DATA \ --name client1 ubuntu bash

Then mount the data container in your application containers

What if you use docker in a VM?

Container

You have an extra layer

Container folder!/src

Docker in a VM

VM folder!/path/to/code

-v /path/to/code:/src

Host OS

Host OS folder!/path/to/code

?

Simplest way: Use Guest Additions

And a VM that supports shared folders. But what if you want to keep using the

lightest weight genius of boot2docker?

boot2docker is great!

Patched boot2docker with vboxsf support

Patched boot2docker with vboxsf support

Pull Request #282-4 add the feature

Patched boot2docker with vboxsf support

https://vagrantcloud.com/dduportal/boot2docker

The UNIX way: NFS, Samba, plan9, etc.

Access via NFS

docker pull cpuguy83/nfs-server

Pull the right image, share a data folder in it, share it with other containers AND the host

docker run -d --name nfs --privileged \ cpuguy83/nfs-server /path/to/share

Access via Samba

docker pull svendowideit/samba

And if you prefer Samba, here’s a shortcut ready made for you

docker run svendowideit/samba data

--links: simple service connections for docker

linked containers

Docker host

/var/volume1

postgresql

/var/volume2

client

--link postgresql:pg

can refer to hostname pg in commands

Sample access to linked container

docker build -t postresql .

Build the image, run it with a name, !link in child container

docker run -rm -P --name pg postgresql

docker run -rm -t -i --link pg:pg postgresql bash !psql -h pg -d docker -U docker --password

Tools, Tips & Hacks

workhorse with a secret weapon

Tiny Core Linux

workhorse with a secret weapon

Tiny Core Aside Awesomeness!

Every time it boots, it is brand-spanking new

Minimal nomadic X desktop for 12MB

Customise your boot2docker/Tiny Core

Tailor the boot sequence in!/opt/bootlocal.sh

List personal settings folders and files !/opt/.filetool.lst

Tunnels, tunnels… and ports

Tunnels and ports

Docker in a VMHost OS

8000 8000

Container

8000 8000

-p outer:inner?

Port forwarding into a container

(boot2docker) ssh -L 8000:localhost:8000

Expose a container port to the host machine

Mass-expose ports with VBoxManage

# vm must be powered off for i in {49000..49900}; do VBoxManage modifyvm "boot2docker-vm" --natpf1 "tcp-port$i,tcp,,$i,,$i"; VBoxManage modifyvm "boot2docker-vm" --natpf1 "udp-port$i,udp,,$i,,$i"; done

To expose all 49XXX ports you can run:

Workarounds section of boot2docker docs

Open ports on live containers with force using iptables

sudo iptables-save

http://j.mp/force-port

Note down the command to open ports of another container

One more thing…

Nicola Paolucci@durdn

Thank you!