Docker on Power Systems

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9.0
César Diniz Maciel
Executive IT Specialist
IBM Corporate Strategy
cmaciel@us.ibm.com
pCV4103 - Docker, lxc, lxd and friends

Session objectives
After this session, you will be able to:
• Understand about containers and how they are useful for
deploying applications;
• Learn how to install Docker on Power Systems and how to
deploy containers;
• Learn basic Docker management commands, how to create
images and how to move containers across systems;

Agenda
●
What are containers?
●
Why containers?
●
Differences between containers and virtual machines
●
Docker on Power Systems
– Installing Docker
– Creating base image
– Deploying containers
●
Comparing Docker to AIX Workload Partitions
●
Managing containers
© Copyright IBM Corporation 2015

What are Containers?
● Two new features enabled containers
● Cgroups and Name spaces
●
Different name space for process
●
Own process space
●
Can run stuff as root (Chroot)
● Concept from Plan9 (1992)
● Done with setns and unshare system call
● Share the same kernel
● No device emulation
● A name space is completely separated
● Full network stack on the new name space
● Own routes
● Own Firewall rules
● Name resolution mechanism
● Mount, PIDs, IPCs,
Server
Host OS
Linux Container + Docker Engine
Middleware YMiddleware X
App
A
App
A
App
A1
App
A1
App
B
App
B
App
B1
Container

What is Docker?
●
Operating system-based virtualization
– Aimed at quick and efficient deployment of applications
in a virtualized container environment.
●
From http://docker.com
– Docker is an open platform for developers and
sysadmins to build, ship, and run distributed
applications.
It runs as an isolated process in
userspace on the host operating
system, sharing the kernel with
other containers. Thus, it enjoys
the resource isolation and
allocation benefits of VMs but is
much more portable and efficient.

Why Docker
●
Fast to deploy
●
Lightweigth
●
Almost no performance impact for applications
●
Very efficient use of resources
●
Ability to pack applications, configuration files, pre-
requisites, etc in a docker image for easy distribution
and deployment.
●
Ability to run different Linux versions and flavors in the
same host system.

Differences between Docker and virtual machines
●
Docker is an OS-based virtualization
– Same concept as Virtualbox, Vmware Workstation, AIX
WPAR, Solaris Containers, BSD Jails...
●
Kernel is shared among all containers
●
Every container runs the same kernel version
●
Kernel parameters are the same for all containers, as well
as network and I/O
●
No strong isolation between containers – processes are
isolated from each other, but all containers run under the
same OS instance

●
Portability
●
If it works locally, it will work on the server, with
exactly the same behavior, regardless of
versions, distro, dependencies
●
Quick boot
●
Faster provisioning
●
Can fit far more containers than VMs into a host
●
Simplified security
●
Only need to fix things on the hosts
●
Lower Costs
●
Fewer operating systems to manage
●
Easy OS patching
●
Greater application mobility
●
Starting/Stoping a container is a about process
management
Benefits of containers
Manual VM Docker
Provision
TimeDays
Minutes
Seconds / ms

● LXC is supported on all IBM Distros available
● Docker on POWER is no different than Docker on x86 platforms from a usability perspective
● Docker is only supported in Ubuntu 15.04 and Fedora 23 at the moment.
● Experimental at RHEL and SUSE
● LXD is only available in Ubuntu 15.04
● http://images.linuxcontainers.org contains ppc64el images
● There is a growing ecosystem of dockerized applications for POWER
● System Z also supports it
– https://www.ibm.com/developerworks/linux/linux390/docker.html
IBM POWER containers support

Installing Docker on Power Systems (after April 2015)
●
Docker now officially supported on
Ubuntu Vivid Vervet (15.04)
– Install the docker package
●
apt-get install docker.io
●
Now part of the Ubuntu distribution and maintained by Canonical.

Using Docker
●
Docker users can install images from Docker Hub, a
public repositores for Docker images
– However, it is x86-oriented. That means that by default,
docker pulls a x86 image from the server.
– Multiarch support for Docker Hub is being worked
- Meanwhile, non-x86 images have distinct names to identify them,
such as 'fedora22_ppc64le'
●
Docker on POWER users can create their own images,
and then can share them by running a private Docker
Hub
●
Most enterprises will probably have their own images in
a private repository for security.

●
LXC is the base, distro independent, container infrastructure.
●
Created in IBM/LTC in 2009
●
LXD is a controller over LXD allowing new features over LXC
●
File-system snapshot
●
Migration
●
Docker is an application delivery that uses containers
technologies
●
Focused on images
●
AnotherUnionFs (AUFS)
●
Was based on LXC in the beginning, now has it own
technology called libcontainer
●
Focused on a few, hopefully 1, process
What is difference between Docker, LXC and
LXD?

LXC, LXD and Docker usage
Similar to AIX System WPAR Similar to AIX Application WPAR

Creating a Docker image
●
Simple ways to create images are:
– Debian Bootstrap (debootstrap)
– Ubuntu Core
●
Cloning a system into an image is also possible
– Allows for migration from virtual machines to containers
– Environment can be customized (i.e. applications installed, etc)
before generating the image for container deployment.

Creating a Docker image using debootstrap
●
From Build and use Docker on the IBM POWER Linux platform
document at IBM developerworks:
●
$ sudo apt-get install -y debootstrap
●
$ curl -o debootstrap.sh
https://raw.githubusercontent.com/docker/docker/master/contrib/mk
image/debootstrap
●
$ chmod 755 debootstrap.sh
●
$ sudo ./debootstrap.sh ubuntu --components=main,universe trusty
●
$ sudo tar -C ubuntu -c . | docker import - ubuntu:14.04
●
$ docker tag ubuntu:14.04 ubuntu:trusty
●
$ docker tag ubuntu:14.04 ubuntu:latest
●
$ sudo rm -fr ubuntu

Creating a Docker image using Ubuntu Core
●
From Ubuntu Core on Docker for POWER
●
Download Ubuntu Core
– Example for 14.04 version:
– wget
http://cdimage.ubuntu.com/ubuntu-core/trusty/daily/current/trusty-core-ppc64el.tar.gz
●
Import the files into docker
– cat trusty-core-ppc64el.tar.gz | docker import - ubuntucore
3ad6c6616b921b10a414238a226fb39eef85d8249ac7d767e84e275aaf90ab65
●
Verify that the image was created:
– docker images
●
Assure that your image is running fine:
– docker run ubuntucore ls

Creating a Docker image using an installed system
●
Creat a tar file with the filesystem structure
– Useful to exclude /tmp, /proc, /sys and other
filesystems not needed in the image
– Example: tar cvf /tmp/ubuntu.tar exclude='sys' exclude='tmp'
exclude='proc' *
●
Import the files into docker
– cat ubuntu.tar | docker import ubuntuinstall
3dcc622c3ef8922cceef85d8249ac7d767e84e275aaf90ab65
●
Verify that the image was created:
– docker images
●
Assure that your image is running fine:
– docker run ubuntuinstall ls

●
Similar concept of OS-based virtualization
●
AIX allows for multiple OS versions to coexist
– Host partition must be on AIX 7
– Hosted WPARS can be AIX 5.2, 5.3 or 7
●
Docker allows for multiple OS versions
– Host partition does not have to be at latest level
– Can host OS versions that are higher or lower
– All run same kernel version, since it is shared by all containers, so
while the OS version may change, the kernel does not

●
AIX WPARs are always persistent. Docker containers are not
– You have to explicitly save the container in order to save
changes made while running
– Application data normally resides on data volumes, that are
filesystems mounted by Docker, and these are persistent –
therefore application data is always saved to disk and does not
require the commit operation on the container.
●
Each AIX WPAR is a separate image. Docker can instantiate
multiple containers from the same image
– Easier to deploy and maintain a pool of similar environments
– Docker automatically assigns a new IP for each instance

Using Docker Containers
●
docker images
●
docker ps -a
●
docker run <container>
●
docker run -i -t <container> /bin/bash
●
docker rm <container>
●
docker rmi <image>
●
docker commit <container_id> <some_name>

Docker demo on Power Systems
●
As root, do:
●
docker -v
●
docker images
●
docker ps -a
●
cat /etc/lsb-release
●
docker run vividcore cat /etc/lsb-release
●
docker run ubuntu cat /etc/lsb-release

Example of running Apache on Docker
●
Based on customization script called Dockerfile
●
Dockerfile specifies image to base installation, adds extra
packages, copy files and configures applications
●
Container started with port forwarding

Dockerfile
FROM ubuntu
MAINTAINER Breno Leitao
RUN apt-get update && apt-get install -y php5 libapache2-mod-php5 php5-mysql
php5-cli
&& apt-get clean && rm -rf /var/lib/apt/lists/*
ENV APACHE_RUN_USER www-data
ENV APACHE_RUN_GROUP www-data
ENV APACHE_LOG_DIR /var/log/apache2
ENV APACHE_PID_FILE /var/run/apache2/apache2.pid
ENV APACHE_RUN_DIR /var/run/apache2
ENV APACHE_LOCK_DIR /var/lock/apache2
EXPOSE 80
CMD ["/usr/sbin/apache2", "-D", "FOREGROUND"]
Instruction set: https://docs.docker.com/reference/builder/

Example of running Apache on Docker
●
docker run -p 8080:80 -d apache
– Starts the container in detached mode, and redirects container
port 8080 to host partition port 80
●
Since it is running detached, control the container using
docker commands (e.g. docker start, docker stop).

Moving a container to other system
●
docker save apache > apache.tar
– copy apache.tar to other system
●
docker load < apache.tar
●
docker run p 8080:80 d apache

Managing containers
●
Many tools for managing docker containers
●
Tools are platform agnostic – they talk to the
docker daemon, so from the tool perspective it
does not matter the platform
●
Docker containers from multiple
systems/architectures can be managed by the
same tool

Managing containers
Shipyard is an
open source
GUI for
managing and
deploying
Docker
containers

Managing containers

Conclusion
●
Containers offer a flexible way of deploying applications
with minimum effort.
●
System resources can be used efficiently, and
migration/deployment of new environments is quick and
easy.
●
Docker integration with cloud management tools such
as Openstack provides rapid instance deployment, and
multi-platform container management.
●
Docker for Power Systems allow all these benefits to
be used on a high performance and high reliability
platform.

© Copyright IBM Corporation
2015
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Docker on Power Systems

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