Jérôme PetazzoniTinkerer ExtraordinaireDocker, Inc

Alexander LarssonPrincipal Software engineer Red Hat, Inc

Portable, lightweight, & interoperable Docker containers across Red Hat solutions

What?

Why?

Deploy everything

•Webapps

•Backends

•SQL, NoSQL

•Big data

•Message queues

•… and desktop apps and more

If it runs on Linux, it will run in a Docker container!

Deploy almost everywhere

•Linux servers!

•Virtual machines

•Bare metal

•Any distro

•Recent kernel

Currently: focus on x86_64.

(But people reported success on arm.)

Deploy reliably & consistently

Deploy reliably & consistently

• If it works locally, it will work on the server

•With exactly the same behavior

•Regardless of versions

•Regardless of distros

•Regardless of dependencies

Deploy efficiently

•Containers are lightweight

•Typical laptop runs 10-100 containers easily

•Typical server can run 100-1000 containers

•Containers can run at native speeds

•Lies, damn lies, and other benchmarks:

http://qiita.com/syoyo/items/bea48de8d7c6d8c73435

The performance! It's over 9000!

Native NativeDocker containerNative Docker container

Is there really no overhead at all?

•Processes are isolated, but run straight on the host

•CPU performance = native performance

•Memory performance = a few % shaved off for (optional) accounting

•Network performance = small overhead; can be reduced to zero

•Disk I/O performance= copy-on-write overhead; can be reduced to zero (use volumes)

… Container ?

Containers look like lightweight VMs

•Own process space

•Own network interface

•Can run stuff as root

•Can have its own /sbin/init (different from the host)

« Machine Container »

Containers are really chroot on steroids

•Can also not have its own /sbin/init

•Container = isolated process(es)

•Share kernel with host

•No device emulation (neither HVM nor PV)

« Application Container »

How does it work?Isolation with namespaces

•pid

•mnt

•net

•uts

• ipc

•user

How does it work?Isolation with cgroups

•memory

•cpu

•blkio

•devices

How does it work?Copy-on-write storage

•Create a new machine instantly(Instead of copying its whole filesystem)

•Storage keeps track of what has changed

•Multiple storage plugins available(AUFS, device mapper, BTRFS...)

Docker: the big picture

•Open Source engine to commoditize container technology

•Using copy-on-write for quick provisioning

•Allowing to create and share images

•Standard format for containers

•Standard, reproducible way to easily build trusted images (Dockerfile, Stackbrew...)

•Hosted services to work and cooperate around containers(e.g. docker.io hosted registry for public and private images)

Authoring Docker images

Authoring imageswith run/commit

1) docker run centos bash

2) yum install this and that

3) docker commit <containerid> <imagename>

4) docker run <imagename> bash

5) git clone git://.../mycode

6) pip install -r requirements.txt

7) docker commit <containerid> <imagename>

8) repeat steps 4-7 as necessary

9) docker tag <imagename> <user/image>

10) docker push <user/image>

Authoring images with run/commit

•Pros

•Convenient, nothing to learn

•Can roll back/forward if needed

•Cons

•Manual process

• Iterative changes stack up

•Full rebuilds are boring, error-prone

Authoring imageswith a Dockerfile

FROM fedora

RUN yum -y updateRUN yum -y install mongodb-serverRUN mkdir -p /data/dbRUN sed -i 's,dbpath=/var/lib/mongodb,dbpath=/data,' /etc/mongodb.conf

VOLUME /dataEXPOSE 27017CMD /usr/bin/mongod

docker build -t jpetazzo/mongodb .

Authoring images with a Dockerfile

•Minimal learning curve

•Rebuilds are easy and reliable

•Caching system makes rebuilds faster

•Single file to define the whole environment!

Docker on Red Hat

Red Hat Enterprise Linux 6

•Available in EPEL: yum install docker-io

•Works in 6.4 and later

•6.5 has more complete network namespace support

•Not supported, but much of the underlying kernel features are

•Packages also work on CentOS

Red Hat Enterprise Linux 7 Beta

•Available in EPEL7 beta: yum install docker-io

•More recent kernel

Fedora

•Available since Fedora 19: yum install docker-io

Storage backends

•AUFS

•Not in upstream kernel or in Red Hat kernels

•Device Mapper

•Contributed by Red Hat

•Works everywhere

•BTRFS

•Contributed by Red Hat

• /var/lib/docker must be on a btrfs filesystem

•Tech preview in RHEL6 kernel

Union Filesystems(AUFS, overlayfs)

Copy-on-writeblock devices

Snapshotting filesystems

Provisioning SuperfastSupercheap

FastCheap

FastCheap

Changingsmall files

SuperfastSupercheap

FastCostly

FastCheap

Changinglarge files

Slow (first time)Inefficient (copy-up!)

FastCheap

FastCheap

Diffing Superfast Slow Superfast

Memory usage Efficient Inefficient(at high densities)

Inefficient(but may improve)

Drawbacks Random quirksAUFS not mainline

Higher disk usageGreat performance (except diffing)

ZFS not mainlineBTRFS not as nice

Bottom line Ideal for PAAS and high density things

Dodge Ram 3500 This is the future(Probably!)

Running your own registry

•yum install docker-registry

•Fedora >= 19

•EPEL 6

•EPEL 7 Beta

Push an image:docker tag 8dbd9e392a96 my-machine:5000/imagedocker push my-machine:5000/image

Use it:docker run my-machine:5000/image

Base images

•Fedora

•Official images available as “fedora”

•Current versions: Fedora 20, rawhide

•CentOS

•Official images available as “centos”

•Current version: 6.4

RHEL base images

•Distribution problematic

•Working on a nice solution

•For now, build base images on entitled RHEL machines

•Use yum –installroot + docker import

•Distribution rules same as any other Red Hat content

Docker,from development to production

One-time setup

•On your servers (Linux)

•Packages (not only RPM, but also Ubuntu, Debian, Gentoo, Arch...)

•Single binary install (Golang FTW!)

•Easy provisioning on Rackspace, Digital Ocean, EC2, GCE...

•On your developer environment (Linux, OS X, Windows)

• In your regular Linux VM (Vagrant or other)

•boot2docker (25 MB VM image)

•Natively (if you run Linux)

The Docker workflow 1/2

•Work in developer environment(local machine or container)

•Other services (databases etc.) in containers(and behave just like the real thing!)

•Whenever you want to test « for real »:

•Build in seconds

•Run instantly

The Docker workflow 2/2

Satisfied with your local build?

•Push it to a registry (public or private)

•Run it (automatically!) in CI/CD

•Run it in production

•Happiness!

Something goes wrong? Rollback painlessly!

Running containers

•SSH to Docker host and manual pull+run

•REST API (feel free to add SSL certs, OAuth...)

•Maestro NG (https://github.com/signalfuse/maestro-ng)

•Many Open Source PAAS built on Docker: Deis, Flynn, …

•And of course, OpenStack!

OpenStack integration

•Nova (OpenStack Compute)

•Provisions and manages virtual machines

•Docker hypervisor driver

•Deploy containers instead of VMs with the same API

•Available in Havana release

•Glance (Image Service)

•Docker registry integration

OpenStack integration

•Heat (OpenStack Orchestration)

•Template driven engine for automated deployment of infrastructure

•Docker plugin

•Allows use of full Docker API in your templates

•Available in Icehouse release

HeatTemplateFormatVersion: '2012-12-12'Parameters: {}Mappings: {}

Resources: Blog: Type: OS::Heat::Docker Properties: Image: samalba/wordpress Env: - {"Fn::Join": ["=", ["DB_HOSTNAME", {"Fn::GetAtt": ["Database", "NetworkIp"]}]]} - {"Fn::Join": ["=", ["DB_PORT", {"Fn::GetAtt": ["Database", "NetworkTcpPorts"]}]]} - {"Fn::Join": ["=", ["DB_PASSWORD", {"Fn::GetAtt": ["Database", "LogsHead"]}]]}

Database: Type: OS::Heat::Docker Properties: Image: samalba/mysql

Outputs: BlogURL: Value: {"Fn::Join": ["", ["http://", {"Fn::GetAtt": ["Blog", "NetworkIp"]}, ":", {"Fn::GetAtt": ["Blog", "NetworkTcpPorts"]}, "/"] ]} Description: Blog URL

OpenShift Containers

•Cloud applications

•Cartridges

•Gears

•Containment of Gears

•UID

•SELinux category

•Home directory

•Cgroup

•Sounds similar to Docker?

OpenShift Gears Version 2

•Use Docker for containerization

•Namespaces

•Layers

•Easier to make cartridges

•Reuse existing Docker images

•Geard

•Combines Systemd and Docker

Docker & Security

History: lots of FUD

•LXC used to be considered insecure

“LXC is not yet secure. If I want real security I will use KVM.”—Dan Berrangé, famous LXC hacker, in 2011.

•Linux has changed a tiny little bit since 2011.

What you should care about

•Limit root access(You don't need root privileges inside containers!)

•Docker will use capabilities to limit damage(But you can re-enable them on a per-container basis!)

•Make sure to protect access to the Docker socket!(If someone can create a privileged container,they can do anything they want on the machine!)

SELinux

•Each container runs in a separate context

•All container files are labeled with per-container context

•No need to write SELinux policy files for containers

•Automatic for non-privileged container if SELinux is enabled

Security upgrades

•Traditional way: apply upgrades on regular basis

•Possible with Docker, but very inefficient

•Docker way: rebuild images on regular basis

•Trivial as long as you use Dockerfiles

•Less risky, since testing+rollback is possible

•Better mitigation of dependency issues

The roadmap to Docker 1.0

Docker 1.0

•Multi-arch, multi-OS

•Stable control API

•Stable plugin API

•Resiliency

•Clustering

Questions?