docker containers deep dive

Docker Containers Deep DiveBest of Red Hat Summit

Will Kinard

October 4, 2016

Agenda

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• Intro

• Containerization 101

• Use Cases

• Build, Ship, Run

• OpenShift

• Q&A

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• DevOps Advisory and Implementation

Services

• Docker Consulting and Integration

• CloudBees Jenkins Consulting

AboutThe Container Enablement Company

• Continuous Integration,

Delivery, and Deployment

• Application Modernization

• Cloud Migration

Container Tech Isn’t New

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2000

2002

2004

2006

2007

1979

2008

2013

ChrootFilesystem isolation

FreeBSD JailsEarly container technology

Linux NamespacesProcess isolation

Solaris ZonesSimilar to jails; snapshots, cloning

Google Process ContainersProcess aggregation for resource management

Linux Control GroupsProcess containers renamed and merged into kernel 2.6.24

LXC Linux ContainersUserland tooling

DotCloud Docker Inc.Introduction of Docker Open Source Project

Docker Open Source Project

GitHub (github.com/docker/docker)

• 2900+ Contributors

• 10,000+ Active Forks

• 34,000+ Stars

Docker Hub (hub.docker.com)

• 6B+ Image Downloads

• 500,000+ Dockerized Applications

• Exponential growth

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0

1

2

3

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2013 2014 2015 2016

Docker Pulls - Billions

What is a Docker Container ?

• Method to run applications in isolation

• Isolation includes namespacing pid, network, users, restricting

root, cpu and memory limits, and providing separate

filesystem

• Many of the technologies are old, but haven't been packaged

in an easy to use toolset before Docker

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“Docker containers wrap up a piece of software in a complete filesystem that contains everything it needs

to run: code, runtime, system tools, system libraries – anything you can install on a server.” (https://www.docker.com/what-docker)

Containerized Deployment and Scaling

Each virtual machine

includes:

- application

- binaries and

libraries

- entire guest

operating system

Containers:

- Include application and all dependencies

- Share kernel with other containers

- Run as an isolated process not tied to any

specific infrastructure

Virtual Machines Containers

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We’re not trying to replace your VMs

Virtual Machine:

Host Virtualization

Containers are used in

partnership with current IaaS

stacks.

Docker and other container

platforms still need a host.

Container:

Application Virtualization

Take advantage of the streamlined

process for VM based IaaS and gain

efficiencies in:

• Higher density workloads

• Scale

• Portability

• Security

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Portability is Empowering

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Portability is Empowering

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Portability is Empowering

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• Containers are designed to be disposable

• New containers go back to a clean image state

• Running containers write to an isolated space

Immutable

• Data is stored outside of the container

• Separates data from your application

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Application Development (Build & Ship)

Problem: Code migration issues: Dev Test Prod. Painful and slow software delivery.

Solution: Developer Self-Service. Automate and consolidate with Docker.

Docker packages applications and their dependencies into containers to allow for easy transport from a

developers laptop to any target test or prod environment. This accelerates the software lifecycle,

increases reliability, and reduces job time.

- Begin with a “Trusted Known State”

- Control and Approve Content

- Track Promotion CryptographicallyDeveloper

Version

control

Sysadmin

QA / QE

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Application Modernization / Cloud Migration

Problem: Legacy applications: brittle, and difficult to change/bug fix/upgrade

Hard to scale, obsolete APIs, costly and difficult to support and maintain.

Solution: Microservices architecture. Technology diversity. Modular boundaries.

Mulit-tier applications can be deployed in parts and each tier is an independent container. Each of the containers

can be used for a single service. Legacy applications can be migrated to the cloud through either a “lift & shift” or

“refactoring” methodology, or potentially a combination.

BuildDocker Images

• Images are the definition. They include

the filesystem, environment variables,

and default entry points.

• Containers are an instance of an

image. They isolate the application

from the host, and even from other

containers.

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BuildDockerfiles

• Write your image definition in a Dockerfile

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• Turn that Dockerfile into an image with

• Develop a new app or “lift and shift” your current codebase

• Union file system

• Multiple RO layers are stacked

• Containers add a single RW layer to

isolate changes

• Layers are cached for fast builds

• Layers are named with a hash inside

the engine

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Docker Images

Docker for Mac / Windows

• Docker tools for the developer

• OS native clients using internally

available virtualization: xhyve and

Hyper-V

• Full Docker CLI from native OS

shell

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Red Hat Container Dev Kit

• Pre-built container development

environment

• Choice of virtualization platforms:

Virtualbox, Hyper-V, Linux KVM

• Eclipse and docker CLI integration

ShipDocker Registry (and Hub)

• Push and pull to central registry

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• Organized as repositories that contain

multiple tags

• Multiple options: run your own, Docker

Hub, OpenShift, 3rd parties

Run

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• Run your image

• Launches a container base on your image

• Options for:

Volumes: link external data into the container for persistence

Networking: bridged, overlay, access with exposed ports

RunDistributed

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• Fault tolerant

• Blue/Green Deployment

• Seamless rollbacks

Distributed

Docker Compose

• Packages multiple containers together

• Defines parameters for ‘docker run’

• Configuration is stored in ‘docker-

compose.yml’

• Allows containers to be scaled, but

without orchestration

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Docker on Red Hat

RHEL

Consistent performance and reliability

Certification and Support

SELinux Security

Atomic Host

• Minimal footprint operating system

• Linux container optimized

• Reliability and security of RHEL

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Red Hat OpenShift Container Platform V3

OpenShift and Kubernetes add the ability to orchestrate

docker containers across multi-host installations.

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• Self-service Platform

• Multi-language Support

• Application Persistence

• Automation

• OpenvSwitch Integration

Load Docker Images to OpenShift!

# oc new-project rhsummit# oc new-app gitlab/gitlab-ce

Thank You!

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Will Kinard

CTO BoxBoat Technologies

will@boxboat.com

@boxboat

www.boxboat.com/blog

Appendix

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This is Important

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• Isolated space for a running application

• All containers run on the same kernel unlike a VM

• Eliminates the overhead of an OS and services

Come Again?

Docker Containers – Run… Anywhere?

Linux:

Kernel Version 3.10+

• Ubuntu 13.10+

• Fedora 20+

• RHEL 7+

• CentOS 7.1+

• Gentoo

• ArchLinux

• openSUSE 13.1+

• CRUX 3.0+

Windows (Really!):

• Docker for Windows

• Windows Server 2016 (TP5)

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Docker for ARM!

Production Operations / Data CenterProblem: Inefficiency of VMs .. O/S duplication… Lengthy boot and replication times.

Hardware, Storage, and Hypervisor costs $$.

Solution: Docker’s containers as a service (CaaS) and orchestration platform. Policy driven architecture.

Deployment flexibility (On-Premise, Cloud, Hybrid).

Docker containers share resources with the host OS, which makes them significantly more efficient than VMs.

Containers can be started and stopped in a fraction of a second. They are lightweight, fast, and maximize

consolidation. Swisscom reduced their VM footprint from 400 to 20 for a database as a service offering, driving

tremendous cost savings.

ControlManage and secure

at scale

PortabilityFrictionless

Movement & Trust

AgilityInnovation at

speed

+ +Build Ship Run

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Isolated

• Isolated filesystem

• Namespace for isolating pids

• cgroups for limiting memory and CPU

• Separate network stack

• Restricted root capabilities

Docker Notary

• Open source project on github

(github.com/docker/notary)

• Trusted cross platform content

distribution

• Platform agnostic in delivering

content

• Publisher key validates integrity

of content

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Portable

• Run Docker containers

unchanged in any

environment, on any

infrastructure

• Move applications at

will between

environments and

infrastructures

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At Scale

Docker containers spin up and down in seconds,

making it easy to scale application services to

satisfy peak customer demand, and then reduce

running containers when demand ebbs.

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