Introduction to Docker

Introduction to

Jirayut Nimsaeng (Dear)

Docker for DevOps and Continuous Delivery WorkshopOctober 11, 2014 @ OSS Festival 2014

Jirayut NimsaengDocker for DevOps and Continuous Delivery Workshop

October 11, 2014 @ OSS Festival 2014

About me● Jirayut Nimsaeng (Dear)● Infrastructure Team Lead

at Proteus Technologies● Scrum Master● Interested in Cloud and

Open Source Technology



Experienced?● Use Vagrant● Read and tried Docker online tutorial● Install and run Docker locally● Build Docker images● Push Docker images to Docker Hub● Written Dockerfile● Deploy Docker images for dev/test/prod



Developer Problems

Developer Local Test QA

Production



What Developer needs

Production-like Quick Repeatable



Docker can solve this problem

Developer Local Test QA

Production



Infrastructure Problems



Shipping with container



Docker can● Deploy (almost) everything



Docker can● Deploy (almost) everywhere

Native On VMs



Docker can● Deploy reliably & consistently● Everything will be exactly the same

– Distros– Versions– Dependencies

● If it works locally, it will work everywhere



In summary



Docker can● Deploy efficiently

– Laptop can run 10-100 containers easily– Server can run 10-1000 containers

● Containers can run at native speeds– http://www.slideshare.net/BodenRussell/kvm-and-

docker-lxc-benchmarking-with-openstack



Docker CPU benchmark

0

2

4

6

8

10

12

14

Docker / KVM: Compute Node Steady-State CPU (Segment Overlay)

docker-usrdocker-syskvm-usrkvm-sys

Time: KVM(95s - 307s) Docker(31s – 243s)

CPU Usage In Percent

Docker Averages

– 0.2

– 0.03

KVM Averages

– 1.91

– 0.36



Docker Memory benchmark

0.00E+00

1.00E+09

2.00E+09

3.00E+09

4.00E+09

5.00E+09

6.00E+09

7.00E+09

Docker / KVM: Compute Node Used Memory (Overlay)

kvmdocker

Axis Title

Memory Used



Docker Memory benchmark

MEMCPY DUMB MCBLOCK0

2000

4000

6000

8000

10000

12000

14000

3823.34393.3

12881.61

3813.38

4395.92

12905.68

3428.95 3461.59

7223.23

Memory Benchmark Performance

Bare Metal (MiB/s)docker (MiB/s)KVM (MiB/s)

Memory Test

MiB/s



Docker I/O benchmark

1 2 4 8 16 32 640

200

400

600

800

1000

1200

1400

1600

Sysbench Synchronous File I/O Random Read/Write @ R/W Ratio of 1.50

dockerKVM

Threads

Total Transferred In Kb/sec



What is Docker?● Platform to help code, test and deploy

applications● Combine with

– Lightweight container virtualization– Work flows– Tooling



Docker image● Docker images are read-only templates● Each image consists of series of layers● Docker use union file system to combine layers

into single image● Every image starts from base image



Docker image layers



Docker container● Docker containers launched from Docker image● Container consists of

– Operating system– User-added files– Meta-data

● When Docker container runs, it adds a read-write layer on top of the image



Containers vs. VMs

Server

Host OS

Hypervisor

GuestOS

GuestOS

GuestOS

Bins/Libs

AppA1

Bins/Libs

AppB1

Bins/Libs

AppA2

VM

Server

Host OS

Bins/Libs Bins/Libs

App A

1

App A

2

App B

1

App B

2

App B

3

Docker daem

o n

Container

Containers are isolated,but share OS and, whereappropriate, bins/libraries



Containers more lightweight

GuestOS

GuestOS

GuestOS

Bins/Libs

AppA1

Bins/Libs

AppB1

Bins/Libs

AppA2

VMs Containers

AppA1

AppA2

Δ

App A1 App A2 ModifiedApp

Bins/Libs

Base



Docker container concept

KernelDocker driver, aufs/btrfs

Host OS (CoreOS)

Ubuntu base Bins/Libs

App A

1

App A

2

Docker daem

o n

Busybox base bins/libs

Python Apache

PHP

MySQL

App B

Dem

o

App B

Prod

Data C

o ntaine r for Ap p A

1App B

CentOS base Bins/Libs

App D

1

App D

2

Python ApacheApache

PHP

App E

Dem

o

App E

Prod

App B

MySQL

Data C

o ntaine r for Ap p A

2

Data C

o ntaine r for Ap p B

Pro d

Data C

o ntaine r for Ap p C

App C

App F

Docker Image Docker ContainerDocker Base Image



Dockerfile● Dockerfile is instructions to build Docker image

– How to run commands– Add files or directories– Create environment variables– What process to run when launching container

● When build Dockerfile, new Docker image will return as a result

● Or we can call result from building Dockerfile is new base Docker image



Sample DockerfileFROM base

MAINTAINER Jirayut Nimsaeng <w [at] winginfotech.net>

ADD build-files /build-files

RUN apt-get update

RUN apt-get install -y openssh-server vim tmux rsync byobu

RUN mkdir /var/run/sshd

RUN sed -i 's/required pam_loginuid.so/optional pam_loginuid.so/g' /etc/pam.d/sshd

CMD /start.sh

EXPOSE 22



Docker Registry● Docker Registry is the store for Docker image● Docker Hub is public Docker Registry like Github● Using Docker client to push and pull Docker image

from Docker Registry● You can create your own Docker Registry



Docker Hub



Docker life cycle

App ADocker Container

DockerRegistry

PushCommit

Host

App A

1 Contai ner

Pull

Docker Engine

App A

2 Contai ner

App A

Image

App A

Image

UbuntuBase Docker

ApacheDocker Container

Apache + PHPDocker Image

Bins/Libs

Apache

Bins/Libs

Apache

ChangeCommit

App A

ΔΔ

Change

App A

Apache

Bins/Libs

App ADocker image



Docker workflows

DockerfileFor App A

Host 1 (Dev/Build Server)

Docker Engine

Image A

pp AIm

age App A

DockerRegistry

Host 2 (Container Server)

1.Build

2.Push

3.Pull

4.Run

Docker Engine

Image A

pp A

Contain er A

pp A P

rodu ction



Docker Use Cases● Docker as Development Environment

Host

Virtualbox VM

Docker DaemonSSH

20352022

22

Web Server

boot2docker-vm

80 1024+

Docker Containers

Database

2035

Hos

t-on

ly

80

80



Docker Use Cases● Docker as Infrastructure as a Service

Server

Host OS

Bins/Libs Bins/Libs

App A

App A

~

App B

App B

~

App B

~~

Docker daem

o n



Docker Use Cases● Docker as Platform as a Service



Docker Use Cases● Docker for Continuous Delivery



Continuous Delivery with Docker

MySQLDockerfile

Host 1 (Dev/Build Server)

Docker Engine

MyS

QL D

ata Image

MyS

QL D

ata Image

DockerRegistry

Host 2 (Container Server)

1.Build

3.Push

7.Pull

8.Run

Docker Engine

MyS

QL D

ata Image

Contain er M

ySQ

L Dat a

BackupServer

2.Get DB Backup

WordpressDockerfile4.Build

RepositoryServer

5.Get Wordpress Code

Wordpr ess Im

a geW

ordpr ess Ima ge

6.PushW

ordpr ess Ima ge

Contain er W

or dpress

Introduction to Docker

Technology

docker image docker

docker hub

docker image container

docker image layers

docker container runs

docker online tutorial

docker cpu benchmarkdocker

containers containers